Seating of spikes / studded tires Some (most?) manufacturers recommend running studded tires on pavement for the first miles to facilitate "seating".
As my commuting route touches little pavement but woods, I see little chance to do this "seating" for 50 km as e.g. Nokian recommends. With a Nokian Extreme, I was not able to see a difference in spike positioning before and after the 50 km seating process.

Hence, I am wondering:

What actually should we think is happening during the seating
process? Fact or fiction?
Why do the companies rely on the poor biker to do the spike seating
    process, why isn't this done by the manufacturer?
How important is this for tire performance? With a pair of Nokian
extreme, I'd guess it took me around 100 kms until I have had these tires
for 50 km on pavement. Over the last 3 years, I lost (and replaced)
not more than a handfull of studs on this pair of tires. With one of
Schwalbe's studded tires, I actually lost around 30 % of the studs
in the first 4 km ride (and returned the tire), with a pair of
Continental, it was somewhat better, but after 50 km of seating, I
still kept loosing spikes at a constant rate. Hence, with the
Nokian, I've got the impression that these were already working
before seating and little changed during seating, with all others,
I've found out that riding on pavement does nothing good to tire
quality.

Peter White has an excellent page on Studded tires.

To quote (answering questions 1,2) him: "Q: Why do Nokian tires have a tag stating that you should ride the tires on paved roads for 30 miles before using them on ice?

A: It's because Nokian is very sloppy in how they install the studs, and doesn't take the time to ensure that every stud is fully seated in the tire tread before shipping it. With some studs partly hanging out of the tire tread, if you ride them hard, the studs can easily fall out. Riding them "easy" is supposed to help seat the studs. Of course this as all just bovine excrement, and those half seated studs can still easily fall out."

On question 3: A few studs missing won't make much of a difference but if a lot of them are missing you lose the advantage of the studs (but you still have the advantage of softer winter rubber).

Also relevant: "Q: How can studs fall out of the tire tread?

A: The main reason studs fall out is riding too aggressively on pavement or on rocky trails. You cannot use studded tires on dry ground the same way you would use summer tires. On ice, you can ride as hard as you dare without damaging the tire or losing studs. But when you reach a bare patch of ground, you must take it easy, lest the studs be ripped from the tread."


Bike Frame Size for MTB Leisure Rides I am looking to buy a bike for my wife on the internet, but the challenge is I do not know what frame will be most suitable for her.

We plan to buy a hardtail for leisure rides on the weekends so we favor upright position.

Her inseam is 82 cm and her height is 172 cm.

I have an option to buy Cube Aim 2017 of 17', 18' or 19.
https://www.cube.eu/en/2017/hardtail/aim/cube-aim-race-blacknblue-2017/

By looking at geometry charts provided above (including stack and reach) is it possible to recommend the frame size which will most likely feel right for leisure rides?

Thanks

Geometries

Strangely your wife's proportions are very close to mine, except I am a little taller. Speaking from experience, in terms of mainstream bicycle fit curves, this  a somewhat long inseam for height, which means

You need a relatively taller stack
You need a relatively shorter reach (a relatively taller inseam means a shorter torso).

This is essentially the worst combination for fitting, which means ordering sight unseen will be difficult to guarantee the best fit. Being marketed with the words "race" makes me concern that the frames may not have enough stack, but looking at the geo chart suggests the stack is decent.

All that said, I think either the 17" or 18" could work, the 19" is too big.  Both the 17 and 18" have nearly identical stack heights, but differ in front-center dimensions (and reach) due to differences in seat tube angles (the top tube length is also nearly identical between the two).

The two sizes also use different wheel sizes.  The 17" uses 29er wheels (larger), a slacker seat tube angle and therefore as has a shorter front to center measurement and a 1 cm shorter reach, while the 18" uses smaller wheels (27.5) and a longer front to center measurement. Perhaps this is to offset handling characteristics of the different wheel sizes?  I would almost phone to confirm the geometries.

Choosing between the two may mean picking a wheel size.  The larger wheel size will be a bit more stable, which could be good for leisure riding. It also has a shorter reach which is good for a shorter torso. Therefore if I had to hazard a guess (danger) I would suggest the 17". Depending on how your legs are proportioned (i.e., femur to tibia) you may need to move the saddle forward if you have long tibias/short femurs, as a shallow seat tube angle is better suited to someone with longer femurs.

Given that you haven't tried the bike, also be prepared to have to change the stem.  Given the long legs, there is a good chance of long arms which could mean a longer stem. Also given that long inseams effectively shorten the stack height relative to someone with shorter inseams, you may need to use a riser stem and possibly a riser handle bars to get the position high enough. A quick check of arm length would be to measure your wing span (an outward facing wall corner can be good for this) and compare it to your height.  Most bikes are proportioned as if the two match.  If you have a proportionately longer wingspan you will likely need a longer stem so that you don't feel cramped, if you have a shorter wingspan you may need a shorter stem so you don't feel stretched out.  Finally, realize that when you flip a stem up (aka riser) you loose reach, so with more aggressive stem rise you may need to find extend the stem length as well.

Geom Charts


How do on-road mountain bike speeds translate to road bike speeds? When cycling on roads on my mountain bike, I generally get around 10-12 miles per hour on a flat surface.

What sort of speeds can I expect to get on a road bike?

On my reasonably flat commute I average around 16 mph on my road bike, but your average speed is dependent on many different factors. A general rule of thumb is that if you are switching from a mountain bike with knobbies to a road bike you will be between 15-20% faster at the same watts/effort.  Typically that's only a change of 2-3 mph.

I teach a bike commuting workshop, and one of the most common questions is whether to switch from a mountain bike to a road bike in order to increase speed.  Typically, I tell people to try three things first:

Swap out your knobby tires for high pressure slicks.  You can find 1.25" -1.5" slick tires that fit mountain bike rims and run at between 75 - 90 lbs of pressure. These will dramatically reduce rolling resistance.
If you have a suspension either lock it out, or set it as stiff as you can.  Locking out your suspension will cause more of your effort to be transferred directly through the drive-train and translate into less loss of momentum from shock absorption.
Try clipless pedals.  Your pedal stroke will be more efficient, again resulting in an increase in speed.

If you do those three things the only real differences between a road bike and your mountain bike will be the weight (which matters a lot more when accelerating than it does when you are already rolling) and surface area resistance from riding in the drops.  But most road bikers don't spend much time in the drops.

Finally, your weight and fitness make a huge difference.  I frequently pass road bike riders while on my commuter rigid frame mountain bike with high pressure slicks.


Replacing an FSA chainring I would like to replace my chainring for a bigger one.

I looked up my bike specs and it comes with a FSA CK-316BT, KSS, 42T chainring. I couldn't find any information about this, so I don't know how to buy a bigger chainring.

Here is a picture of what I am trying to replace, I am trying to replace only the chainring and not the whole chainset.

My question is, what type of chainring can I use to replace my current one?

The main limiting factor is chainstay clearance.  If your chainrings touch the chainstay it will wear and weaken and eventually fail.  So the first thing is google your bike frame and see what maximum size chainring its rated for.  Do this first.

Once you have that info, get onto Sheldon's gear calculator https://www.sheldonbrown.com/gear-calc.html  and play about with the numbers.    Will changing from 42 tooth to your maximum tooth give enough difference to notice?

Finally, print this PDF https://cdn.shopify.com/s/files/1/0230/9291/files/BCD_finder_tool_v2.pdf in 1:1 scaling, then put your chainring directly on it and see which BCD matches.
Note that 102 and 104 are very close as are 94 and 96.

Armed with those numbers then you can go shopping.  Make sure you fit a new chain (it needs more links anyway) and a new cassette.


Unfixable brake disk rubbing I ride a Rabeneick TS5 2017 Alfine 8, bought in 2018, with about 5000km on it (mostly commuting on asphalt, in all weather (mostly dry), some easy forest trails). It has BR-M395 hydraulic disk brakes  with resin pads, with BL-M395 levers and SM-RT54-S 160mm rotors, vertical dropouts, a bolt-on-axle hub dynamo (probably DH-3D37-NT) in the front, Alfine 8 IGH in the back. I frequently experience disk rubbing (both rhythmic and continuous) on both wheels. I usually managed to fix it by re-centering/adjusting the brakes and/or bending the rotors by hand, but after braking hard the noise often returns.
It got continuously more complicated to adjust, until a while ago I was unable to make the front brake silent, so I brought the bike to a LBS, who installed new pads. It was fine at first, but after a ride the noise returned. Being fed up (and also because the LBSes here are ridiculously expensive), I bought new rotors and the tools to install them. It took ages to adjust the wheel, brake, and rotor to make them run silently.
Today I got a flat and had to take off the front wheel to take out the tube and submerge it in water to find the whole. Patching it and putting it all back together was easy enough, but the brake was (of course) misaligned again and I again had to fiddle forever to adjust it properly.
So the questions are - do all (hydraulic) disk brakes need that much care? Is just this model particularly bad and more expensive ones are more reliable? Do I need to replace the brake itself (rather complicated because of the hydraulics)? Should I just ignore the noise? Am I doing something wrong? Should disk brakes only be used with thru-axles as the wheel position is fixed? Just as an example, the Surly Troll "expedition touring" bike has vertical dropouts and disk brakes too. If you get a flat in the middle of nowhere and had to take a wheel off to patch/replace the tube, how would you re-adjust the brake? Sounds like a nightmare!

Noise after hard braking is normal. The rotor heats up and warps slightly.
When you got rubbing after reinserting the wheel, that shows you didn't align the wheel correctly. You need to be applying as much downwards force as possible while tightening the QR in order to seat the axle in the dropouts. The one-sided force from tightening a QR skewer tends to twist the wheel askew, so you need to be pushing down the whole time to counteract this force. You can practice this by repeatedly removing and reinserting the wheel: once you no longer get rubbing, your technique is spot on.
And yes, you should just ignore the occasional noise. There's no safety issue or anything, and unless you've already purchased $1200 CeramicSpeed jockey wheels, there's no point chasing the performance benefits of eliminating minor rubbing either.


Adjust rear derailleur - strange behavior So I'm trying to adjust and fine tune the bicycle, but there's something that quite doesn't match up anything I've seen or read online about rear derailleur adjustment, most manuals go this way.

Adjust limit screws.
Fine tune cable tension.

2.1 if it's not going from the largest gears to the smallest, tighten, remove tension

2.2 if it's not going from the smallest gears to the largest, loosen, add tension.

My problem is that after getting the limit screws right, it fails in both directions, that means, going from the largest to the smallest and from the smallest to the largest both fail, so adding and remove tension won't work as fixing one would only make the other worse. However this only happens in the higest gears, the climbing gears shift perfectly, where the fast gears would randomly fail in both directions.

Basically everything is new, and yes, it is definitely matching parts, it was working well a week ago, now it feels like the changes in the smallest cogs are too small to trigger anything.

I understand how all the mechanism works with the exception of the B-screw.

Just a comment when I set up my limit screws it seems like I can push the derailleur a couple of millimeters in the horizontal axis and an entire centimeter in the vertical axis, only in the smallest cogs, I could swear to god that's why, it's sticking to the previous position and hence it fails in both directions unless cable tension is able to overcome that, except that there's not enough cable tension to overcome the stickiness of the derailleur in the smallest cogs, but the derailleur is new, some sort of setting or what?

EDIT: I just added oil to the derrauilier and it seems less sticky and it got better, but it still fails a lot to switch.

From the video it does indeed look like the derailleur is being prevented from moving properly. You need to determine where the cause of that is. I think that most likely it's the cable or housing that is the problem.

1) Examine the shifter cable and housing, make sure there are no kinks, tight radii bends etc. Make sure the housing is fully inserted in any bosses, including shift levers and derailleur barrel adjuster. Make sure there are no obstructions to any sections of uncovered cable.

2) Remove rear wheel, shift gears at the levers and check the derailleur is going through its full range of motion and not sticking, especially on upshifts (cable loosening).

3) Disconnect the shifter cable from the derailleur, move the derailleur through it's range manually. Check there is no stickiness and the parallelogram spring is positively returning the derailleur to the high (outer) position.

4) Hold the shift cable at the derailleur end and put a little tension on it, run the shifters through all the gears. Check the cable is moving freely as you go through all the gears.

This should make it obvious if it is the derailleur itself that is sticking, or the cable, or possibly the shifter.


How much play in a spring suspension fork is normal or safe? I have (had) a basic Suntour spring fork on my hybrid and when I took it into the bike shop a couple months ago I was told the fork was excessively worn and needed to be replaced. Long story short I went cheap and put a solid fork on it which it turns out massively changed the geometry to the point were I'm putting pedals into the dirt on bench cut trails, even without roots.

I still have the old fork and it's something near 2 inches taller than the new rigid fork. I believed the shop at the time when they said it was worn but now I'm wondering. Holding the upper and lower portions of the fork I can feel it shift slightly when I try to bend it but it doesn't move visibly that I can tell.

Is it still reasonably safe as-is, should I get new bushings from Suntour for it and see if that helps, or should I accept it as dead and spend the money on a new suspension fork that is the right height?

It doesn't sound like it's dead yet.

Play means that the bushings are worn out.

If you continue to ride it just how it is, you will end up damaging the stanchions. However, it is not dangerous to your personal safety to do so.

Replacing the bushings seems like the best option. I doubt the stanchions have any damage if it's only a tiny bit of play like what you're describing.

It is also worth noting that the responsiveness of the fork (how well it "floats") would likely be much improved if you gave it new lube and bushings.


Mino quick link geometry adjustment, what can I do with it? My 2017 Trek Fuel EX 5 has a Mino quick link in the rear triangle, but I don't understand what position I should put it in.

Could somebody explain what purpose each position is best suited for, e.g., jumping, technical, XC, DH ?

Thanks.

Mino is a link that changes the geometry of the bike.

High lifts the BB (about 10mm) and steepens the head tube (1/2 degree) compared to low.

With the link set low the bike will be more stable but less agile, especially on down hills. With it high it will be more agile but less stable, with lower chance of pedal strike (due BB height). The difference is small, and may be imperceptible to an unskilled rider.

As far as position, the best position is the one you like. There is no right or wrong. Try it on the trails you ride, and decide where you like it. Generally DH you would probably want it low, XC high.

It will be far more important to get the suspension properly tuned up, tire pressures and bike fit correct before worrying about the link position.


Cassette HG 51, which chain? I need to replace my cassette (Shimano HG30 8speed 11-32) and chain (KMC Z7) that is currently on my bike (pinnacle Aura), however these parts are now discontiuned and I need to find the replacments. I have been recommended the HG51 cassette but don't know which chain to get.  Can anyone help?

Any 8-speed chain should work. If you want to be absolutely sure, get one made by the same company that made the cassette. I believe Shimano still makes several 8-speed chains.


Bosch Nyon and W-LAN I have an electric bike with a Bosch engine (Performance Line) and a Nyon Computer.

The Nyon is not able to connect to WPA or WPA2 password protected networks. If I remove authentication on my network I am then able to connect (and was able to update the device).

As Bosch does not give any way to communicate with them (support is only through the dealer which I doubt will be able to help) I am trying here (if there a is more technical forum or exchange site please tell me)

Now the question:

Is it possible to connect to a password protected WiFi Network (as stated in the manual) or is there a known bug?

Edit

With the latest update (August 2015) WPA2 seems to work. 802.11X is still completely broken (the Nyon does not even see/show the Network SSID)

I was able to connect to an unsecured WLAN with my Nyon. I updated the Nyon and tried to connect to a secured network again, but no luck! I'll try to contact Bosch support about that problem too. I see following possible workaround's in the mean time:

If you only need to sync your cycling data, you can use the mobile app and connect via Bluetooth.
If possible with your WLAN router, enable an unsecured guest network and connect your Nyon to it. Switch off the guest network if you don't use it anymore.
Remove security from your WLAN while you need a connection from your Nyon. Don't forget to restore security settings, as soon you are done working with your Nyon!

Be aware that as long as you run a unsecured everybody within reach of your WLAN router can access your network and listen to the traffic on this network. Best stick with mobile app/bluetooth and use unsecured WLAN only to download maps or update the Nyon software.


Geometry measurement, from where to where I'm looking at http://www.specialized.com/ca/en/bikes/road/tarmac/tarmac-comp#geometry and would like to know what "Seat-Tube Angle" means. For say the 56, I would assume that angle is like this

Where the horizontal black in parallel to the earth, the red is the bike frame and the blue is the angle.

Am I correct in my assumption?

Thanks!

Yes, you are correct. The seat tube angle is measured relative to horizontal.

There is also a separate angle called "derailleur angle", which is measured between the seat tube and chainstays. You'll rarely find it specified in the geometry data though...


What is it called when you ride around on your front wheel? I know a wheelie is when the front wheel is in the air but does it have a different name for when the back wheel is in the air?

Rolling along balancing on the front wheel is called a "nose manual".
If it's braking to a stop while balancing on the wheel it's a "stoppie".
If it's braking to a stop suddenly with the rear wheel lifting and no front wheel rolling it's called an "endo".


What's the best way to fix carbon to titanium? I'm building (experimenting if you wish) something out of the old bike parts and I need to fix two parts together one titanium and carbon.

Basically the parts are two tubes one made of carbon of a lower diameter and one made of titanium. So the carbon tube goes inside the titanium tube and I need to find a way to fix it inside for good. I guess it should be some kind of a hardcore gluing.

If anyone have any experience or suggestions please share. Thank you!

There are many companies today producing "lugged" frames out of aluminum/steel/titanium with carbon fiber tubes.  Seven Cycles is one example, but there are others.  Additionally, some people are independently making carbon frames with lugs that have been created using 3D printer madness.  Reading various forums and the last link, 3M, Loctite and West System all make epoxies that would work for such an application.  Your best bet would likely be to contact the company and have them recommend which product would be appropriate.

All of this assumes that you are trying to lug a piece that will be under compression.  Lugged bicycle frames work because the triangle largely experiences compression forces which actually force the tubes into the lugs.  Forces acting to pull the tube out of the lug are more rare and the epoxy acts mainly to hold the setup together and isn't as "structural" (bad use of the term) as the lugs or tubes.  If this is not what you are trying to accomplish, you may look for a different solution since gluing/epoxying together two pieces that will be under tension will rely on the strength of the epoxy to hold them together and likely not be appropriate for the forces generated cycling.


What gauge wire is used for dynamo hubs and lights? I have some non-standard bikes to hook up so rather than ordering the kits with fixed length wires, I want to just order appropriate double strand (or coaxial) wire in bulk, along with the connectors, and get the job done that way. I can't seem to find the standard size used for this job, however. Appears to be about 22 AWG.

Won't matter much, 22AWG is rated at about 1AMP for power transmission and 7AMP maximum current (i.e. that is around the current insulation starts to melt), is plenty large enough to carry the current from a dynamo (a few hundred milliamp's) and provides a strong enough wire that it won't break easily when in use.  A size or two smaller or larger won't hurt.


Denied warranty claim on carbon bike due to impact? I saw a little crack on the bottom section top tube of bike which is a kestrel talon. I took it the bike shop to see if it was covered under warranty. I have fallen once or twice from the bike but I have not been in any accident at all.

The bike shop took pictures and sent it to Advanced Sports and they asked him to send the frame to them. Once they took a look at the frame they denied warranty claim saying that the issue is caused by some kinda impact.

They do offer a replacement frame for a discounted price which is like 500$.

The question is should I get the frame back and get it fixed or get a replacement frame only?
Update: went ahead and ordered a replacement.

I'd not take this "statement from authority" as an absolute truth.  Ask them to prove its impact damage.

Depending on your location, there may be ombudsman services or small claims courts where you can pursue them for "failure to honour warranty contract"

If the frame is replaced, they will keep the old one and you look after your new one.
If the claim is rejected, you should contact a carbon fibre specialist and have it checked out.  If a repair seems worth doing and affordable, go ahead.
Otherwise don't be a sucker to buy the "discount" frame.  Consider another brand who does honour their warranty.  It'll happen again.


Chainring just don't know when to let go My chain needed to be replaced for half a year ago and I've finally replaced it. But after replacing it, I've notice a lot of clicking noise from the chainring area. and when I go check it, I saw the chain sticking to the bottom side of the chainring while I'm pedaling.

I went back to the shop to tell the owner what's wrong, he just say it's the friction from the chain and the chainring, it will be gone if I just ride the bike for a month or so. Now the noise is still there but not as loud as before, but is there something I should have done that doesn't require to wear off the bike chainring? Cuz I bought the chainring a few months ago.

Update: my old chain needs to be replaced but I kept on using it for almost a year already, not sure if that's the reason why.

Here is a pic of the chainring.

This is called chain suck. One possible reason is worn chainrings.

In the question it is mentioned that the rings were used with worn out chain. This wears out chainrings quickly.


Trouble removing a(n old) 700x23c tire I've been riding an early 90's Italian steel timetrialer (D'accordi TT0.9) for a few months, front tire has a slow leak that needs to be replaced.

The problem is that I can't get the bead totally over the rim.

It's the front wheel, a Campi (it says Lambda Strada on it somewhere), the tire is a 700x23c DSI I have no idea how old it is, though it doesn't seem to have a massive amount of wear.  I'm a bit of a noob on the bike maintenance front (trying to correct this), so while I think I understand how to get a tire off a wheel, perhaps I'm going about it incorrectly.

Basically I've used used a couple tire levers and gotten about 6 inches of tire over the rim, I'd post photos but I'm new so...), but cannot for the life of me get the lever to pick up the bead anywhere else on the wheel.  While I know from reading other things that other tires on these rims may well be easier to work with in the future, I'm currently faced with the more immediate problem. Does anyone have any advice for getting the rest of this tire off the wheel?

Update: Adding that, I can see the rubber tearing away around the bead a bit I try in vain to get the lever under the bead. Do know if this is relevant to my problem, but it is a bit worrying ...

How about grabbing the tyre where it's started to come off with some pliers. Then put a foot on the wheel, and pull hard.

Good luck! I know this can be really frustrating, because I had a tyre that was tightly stuck before. If it really won't come off, buy a new tyre that looks more forgiving, and chop the old one off with some wire cutters or a knife.

I decided to replace my too tight tyre even though I eventually did manage to get it off and back on because I considered that if I ever had a flat away from home and all my tools, there would be no way I could repair it, and I didn't want to risk being stranded a long way from home.


Where can I find statistics on the growth of US & worldwide bicycle use and business? I'm having trouble finding up-to-date information on the growth of cycling in the US and across the globe. How rapidly is the cycling industry growing? In what country is cycling growing fastest? Is the industry growing in lock-step with new cyclists or are established cyclists just purchasing more cycling goods? Where are the most new cyclists hopping on bicycles?

Many questions, I know, and don't expect them all answered. More broadly: Where can I find, or can anyone provide, statistics that demonstrate the trajectory of bike use?

There's some US-specific stuff collected by the LAB here: http://www.bikeleague.org/media/facts/ — click through and you'll find spreadsheets, etc.  Looks like they mostly have 2000–2009 data.

It's pretty typical for that kind of data that 2009 will be the latest year available. With the type of agencies and data involved, it can easily take a year or two to compile into a useful report.

I was looking at a recent report for data in my local area (long pdf, start at page 85) and they reference the National Bike and Pedestrian Documentation Project as the new (2009 and later) standard used for counting bicycle usage.

Looking through their documents, they mention:

Rails-To-Trails Conservancy
Institute of Transportation Engineers.
National Household Travel Survey.

The NHTS seems most promising, but they don't have a ready-made report for what you want and their data samples are roughly every decade, not annual.

Also promising: US Census Commuting Data, but it looks like you'll have to dig down into the more raw data to get what you want, since the easy to find report only has the latest census and puts bicycling in an "other" bin.


Looking for suitable mudguard, based on tyre size Will my bike (tyre size 700 x 23) be suitable tobe fitted with this mudguards (universal 28” & 26”)???

Thanks all.

Yes.

A 700c rim with a 23"mm tire is under 28" in diameter. The max tire width is specified at 40mm.

The "28inch" spec is a bit confusing as it's not a common wheel size (700c, 29" etc). I'm guessing a 700c rim with a 40mm tire is about 28" in diameter.


Is the 'shark wheel' a good idea for a bicycle? I recently found a product that is a redesign of the common wheel.  It's branded as the 'shark wheel'.  It's basically a wheel where the rim is circular but bends like a sine wave.  Simple idea but very interesting.

Currently, the company only has skateboard wheels in production.  However, I recently saw the owners give a presentation where they demoed larger wheels for strollers, wagons, etc.  I can't help but wonder how long until someone rigs something like this onto a bicycle hub and rides it.

The stated benefits are that the wheel has, or can have, a thin tire with low rolling resistance but it grips like a fatter tire because of the way in which it travels over the ground, constantly changing velocity.

Below is a picture of one of the wheels.  My question is can this design be applied to a bicycle wheel, and, if so, would it be more performant is certain cases, e.g. off road?

On a skate board type application it is effective

On a bicycle it is not effective and impractical to implement

On a skate board you want a wide contact patch. On a skate board you absolutely don't want the wheel to tilt.  The idea is to keep the width but reduce contact area.  The reduced contact patch has lower rolling resistance. Within the virtual flat contact surface are circular surfaces that will shed debris (small rocks).  They can also can go with softer material so you give back on rolling resistance but get softer ride and more grip.  They are not taking over the skate board market but they have a niche and it may grow to dominate.  It is more than just a fad with no real value.  And some people  will buy it because it looks cool.

Basically none of that scales to bicycle.

A bicycle leans and as soon as you lean a shark wheel it is no
longer round.
That is a show stopper.
Even if it stayed round on a lean the extra width on a bicycle with comes
at large expense.
A spoke type design would not work.  Would need a solid wheel.
Would have to be a solid tire.  Pneumatic would push the tire off a curved rim and put stress on the rim.


How can I improve my downhill mountain bike as a commuter? I have started commuting recently to work and university with my bike. It's not ideal, but as it is, I'm not willing to invest in a new one, hence why I'm looking for suggestions to improve my current one.

Weight is around 20-22kgs. The wheels are Schwalbe Big Betty Performance Line 26" x 2.40" on the front, Kenda Kinetics 26 x 2.35 on the rear.

On my way to work and uni I'm mainly on roads but do encounter some cobbled roads and uneven terrain. I previously used the bike on downhill trails.

As of right now, I'm averaging around 8-9MPH or 15KM/H. I'd love to get that up to 20KM/H.

You really can’t change it that much. A dual-suspension downhill mtb will always have limitations, most notably its weight, wheel size and width,  and geometry.

Instead, get a used, 1970s, steel, road bike for your commute. It should cost you roughly $50-150 euros or dollars.

You’ll be amazed at how light a road bike (even a steel antique) will feel compared to a mountain bike. My 1975 Peugeot MX-18 weighs just under 11kg (I did swap the steel rims for alu ones). This is half the weight of your mountain bike!

A road bike, even an old one, will be faster over paved surfaces and learning how to “float” over cobblestones and rough surfaces will help your mountain biking skills.

Finally, since a used beater is so cheap, you won’t worry as much riding it in all weather conditions or about bike thievery.


When is a good time to change tyres due to age? When should I consider changing tyres due to age? The tyres in question are five/six years old Continentals.

You can tell a tire is ready to be changed when the rubber is brittle or when you're losing tread. I've found that tires that haven't been used or many years can sometimes get cracked and the rubber loses its flexibility, particularly in the sidewalls. If a tire is decades old, still has tread, and the rubber feels flexible, there's no reason to not use it.


Removing headset cups from 44mm head tube I have a 2015 Salsa Colossal with a 44mm head tube.  The upper cup is a ZS44/28.6 (1 1/8") and the lower cup is EC44/33 (1 1/4").  I need to punch out the cups, so I bought a Park Tool RT-1.  It states that it works with 1" to 1 1/4" cups and Park's website explicitly says it works with ZS44 and EC44 cups.  The problem is that the flared part of the tool passes right through the lower 1 1/4" cup and barely catches the upper 1 1/8" cup.  I could direct the tool at one side and then the other, but I thought the main purpose of the tool is apply pressure evenly around the cup.  Should I have bought the bigger RT-2?

The park tool RT-1 is the original headset cup removal tool for 1 1/8" headset cups.

The RT-2 oversized headset removal tool is the correct tool for 1 1/4 and larger cup sizes.

That said, the RT-1 can be used, when directed carefully, on 1 1/4" cups also.

In my opinion, Park is too liberal in stating what larger headset sizes the RT-1 can work with, but it isn't technically wrong.

Recently manufactured RT-1 tools have more flare to the ends than the older RT-1 did, which may account for the difference as well.

Depending on when and where you bought yours, you may have the pre-1 1/4" version. Either because it's new/old stock, or because it was used...


Bike type xc ht or cx? I am a newbie on bikes and i want to buy one. I want to buy a bike that i can cover some small city road distances ~30km daily with comfort and to be able to go on some mountain trails when i got time on weekend so i can get some experience in dirt trails and if i like it to consider in the future buy a fs downhill bike. I think that cross country hardtail with lockout suspension is the type of bike i search! I want to give a budget about ~1000 - 1500 euro. I don't have any riding experience so it would help me a lot if someone has a xc ht that he also uses it for that kind of distances in city road, for some feedback! If Its too unconfortable i may consider to buy a cx!

Any suggestion would be useful.

Thanks in advance!

An XC MTB should certainly be workable for what you want. Depending on the trails and your skill level a cyclo-cross bike would also be a reasonable choice as well.
There are lot's of bikes like this on the market now.

http://www.konaworld.com/jake_the_snake.cfm

If the trails are mostly packed dirt with few rocks, then a CX bike works pretty well off road and will generally be a much nicer commute bike. The rougher the trail, the more suspension helps.

In terms of getting an XC MTB, the key things to look at are the components and quality of the fork. At that price range I would look for a good quality Fox or Rock Shox fork that used an air chamber. Shimano SLX or XT components or the equivalent SRAM ( Nice chart here http://www.choosemybicycle.com/in/en/bicycle-tips/know-your-bicycle/sram-mtb-component-hierarchy )

The important thing to remember is that you won't get it exactly right the first time around. Until you're out there and riding you really can't know exactly what the right bike for you is, and the right bike will change over time as you gain fitness and skills. Components from the major manufacturers, even at the entry level are all of very high quality these days. As long as you get a bike that fits you, it's pretty hard to get the wrong bike these days. Take your budget and reserve 30% for getting upgrades and tweaks as you learn more about exactly the kind of riding you like.

The one caveat is extremely cheap bikes sold at large retailers. Basically, you get what you pay for.


Changing crankset - axle length I am looking to replace the crankset, cassette and chain on my commute bike as they have gone rusty.

Currently, it has Nexave T303 cranks on. I have not managed to find their official specs. On http://www.sheldonbrown.com/bbsize.html they are listed as 47.5 chainline, 117.5 spindle (axle ?) length. (supplied by users)

Looking at replacements such as Shimano Altus FC-M311, they show chainline of 50mm, and axle length 123mm. I assume 2.5mm difference in chainline won't make a difference on shifting (given this is not a race bike).

Should I be concerned about axle length? Or should I just buy any cranks that fit square axle?

The cranks are fixed at the ends of spindle, so the spindle length affects chainline. The final chainline is determined by axle length and crank design. In your case, your existing spindle is 5.5mm shorter than the recommended one, so the chainline would be 2.75mm inward from the spec and match the chainline of the previous crank.

Cranks and chainrings are made of aluminum, which does not rust by itself. You should be able to remove rust from chain by wiping.


"Proper" cycling posture on a road bike with drop bars? Sometimes I feel a little pain in my lower back after cycling (nothing too long, mainly cycling around London for general commuting...5-10Km). It could be due to a number of reasons (I have a bad back anyway), but I would like to eliminate bad cycling posture as a possible cause.

I can only find one mention of cycling posture on SE, but it refers to flat bars:  Proper Posture on a flat bar road bike.

My bike is the correct size for me I believe, using the old "its just the right height for my crotch..Ouch!" measurement.

Does anyone have useful sources of information how to achieve the correct cycling posture?

Whatever works.  The main advantage of the standard drop bar is that it offers you multiple hand positions and multiple postures.  In a sprint, or driving into a headwind, riding fully on the drops cuts wind resistance, but for less intense riding one of the several hand position on the top bar or on the hoods is usually preferred.  And on long rides the ability to change positions from time to time is invaluable in terms of hand/arm/back comfort.

And there is no one "right" height for your bar.  If you're a real aggressive rider (and young and limber) then a lower bar position may be for you, but if you're somewhat more casual there's nothing wrong with raising the bar (so to speak).  And you may also want to consider adjusting your "reach" by changing the stem -- not everyone's torso is the same length.


Why were press fit bottom brackets invented? What I've seen online says that it allows for lighter and stiffer cranksets becasue the axle can be a larger diameter. However, FSA sells BSA threaded outboard bearings compatible with BB386 EVO which has a 30mm axle. This leaves me wondering why press fit was even invented. Maybe it was invented so manufactures could sell us more stuff but even pros use it so there must be a decent reason.

Carbon is the dominant frame material in performance bicycles. You can't thread carbon. There are two ways to get bottom bracket cups into a carbon frame: bond (industrial-strength glue) an alloy sleeve into the shell, or use a press-fit system. You are potentially adding several manufacturing steps by adding a threaded sleeve to a carbon frame, and the sleeve could be considered redundant material compared to a press fit interface.
It's commonly been stated that press fit BBs are cheaper for the bike manufacturers to produce, and this is consistent with the argument above. However, economic theory would suggest that in a competitive marketplace, consumers should see those savings. Also consider that we use press fit for headsets, and these have generally been trouble-free. That redundant interface might take up space that we might trade for enlarged (and thus more durable) bearings. Last, while I've repeatedly said that small amounts of weight make little difference in cycling performance, the fact is that weight is easily measured, and there are many weight weenies among performance cyclists. Purchasers have been sensitive to bike weights, and press fit systems are lighter because they use fewer parts.
(The argument above draws from the Youtube vids of Raoul Luescher, who has extensive experience in aerospace carbon manufacture and repairing, and who examines and repairs carbon bikes.)
The trouble with press fit
In practice, the main issue with press fit is the tolerances, i.e. some of them are oversized, and BB cups fit loosely, and they creak.
All components on bicycles have a specified dimension, and they have a variance around that dimension, e.g. PF30 shells from manufacturer X may have a mean diameter of (these are imaginary example numbers) 45.95 millimeters, with a variance of 0.5 millimeters. Tolerance may more properly refer to a set of engineering standards, which state the intended dimension and the allowed variance around this dimension. Refer to the below engineering diagram from FSA describing a BB 386EVO shell from this BikeRadar article (which is naturally about creaky press fit BBs):

Continuing with the example above, I think the diagram says that this shell has a nominal width of 46.00mm, with an allowed tolerance of 0.05mm smaller and 0.00mm larger. (Recall that if the shell is slightly small, you can just press the cup harder into the shell and the material will deform slightly, but if the shell is too big, you get creaks.) I am not familiar with industrial quality control, but I would expect that both the factory and the bike company probably check (or perhaps they should be checking) the dimensions on a sample of frames in each batch. I supposed they would scrap individual frames that aren't in spec, and they may scrap the whole batch if there are enough out of spec frames. If the bike company is the one finding this issue, I would expect that they'd place some irate calls to the factory.
Whatever they should be doing, not all frame manufacturers have been able to maintain all their frames within the engineering tolerances. Recall that carbon frames are laid up by hand - workers lay several hundred sheets of pre-glued carbon fiber together in a mold, then the mold gets heated under pressure. This process may be inherently more variable than, for example, forging or CNC machining metal parts. This has led many to be skeptical of press fit in general. I am willing to take Luescher's argument that press fit is theoretically better than threaded, but he does acknowledge that in practice it is not.
One other possible issue with press fit BBs is that you often have to replace the bearings. It is not ideal to repeatedly press in and press out the cups from the frame, as this will wear the surface. We do not have this issue with headsets, because we very rarely remove and reinstall them. In contrast, BBs are subject to much greater forces than headset bearings. BBs are probably subject to more contamination, not least because they are lower and in the path of spray from wet roads. In some BBs, you can remove the bearings independent of the cups, or the bearings may be designed to have their seals removed and replaced (e.g. Chris King designs a little gap in their seals and they explicitly instruct annual regreasing). You can't do this with all BBs, and you would need to replace the entire unit, cups and all. On some press fit designs, this is compounded by the fact that the design places greater stress on the bearings, thus shortening their expected lifetime. For example, PF30 has relatively narrow spaced bearings.
There are post-hoc fixes, and they are unsatisfactory
The thread-together type of BB the OP described is a partial solution to BBs that creak because they fit too loosely (i.e. the shell is too big). Another partial fix has been to add retaining compound when installing the BB. These fundamentally won't fit a BB shell that's too far out of spec.
For press fit to work, the factories need to achieve better tolerances. I would guess that this is possible, but these should raise the prices of the frames. I suspect the increases might not be very large, but I don't have industry experience, and it might be more complicated than that. Also, consumers may be price sensitive enough that even a small increase would dissuade them from buying a bike.
Regardless, if you read between the lines of this Cyclingtips review of the Factor Ostro VAM and the comments, you'll see some statements from Rob Gitelis, the owner of Factor. Factor actually owns its factories in Taiwan, and makes bikes for other companies as well. Gitelis seems to imply that he could achieve the necessary tolerances with press fit, but Factor chose to use a variant of an existing threaded standard (discussed below) due to market pressure. Gitelis claims the threaded interface adds 30g of weight to the frame.
The rise of threaded BBs
For readers who are generally interested in the topic of alternative BB specifications, this Cyclingtips podcast interviews some of the framebuilders who proposed the T47 oversized threaded BB standard. It is mainly used by small framebuilders, but Trek appears to be moving its lineup of carbon bikes to T47 BBs. Factor did this with its latest bike, linked above. Specialized appears to be moving to a threaded standard, which I believe is actually the reliable old BSA standard (NB: you can fit a crank with a 30mm spindle in a BSA shell, and BBs are increasingly available). An interesting side note: a metal PF30 frame can be threaded to the T47 standard, although this task is likely to be beyond the capabilities of an average bike shop. Although T47 shares many of PF30s dimensions, PF30 bearings sit inside the frame, but T47 bearings are placed outside the shell. Thus, they are more widely spaced than PF30 bearings.
Side note: Facing frames
This article by James Raison on Lavelocita.cc discusses the practice of facing carbon frames - that is, removing excess material on the surfaces that interface with other components so that they're in spec, e.g. making the disc brake mounts totally flat, enlarging a BB that is much to small, or aligning the BB and headset surfaces if they are misaligned. If the surfaces were out of spec, this can cause reduced bearing life or brake noise. Note that if the issue is that the BB shell was made too big, facing won't do a thing, because a bike store can't simply add material to the shell.
Because I have already digressed, here's another article by the same author on the practice of facing metal frames - yes, their bottom brackets could also creak, although in that case you could face the shells more easily than on carbon, or you could chase the threads if you damaged them. In general, facing is a very labor-intensive process that requires specialized tools, and few shops do it. However, many frames come out from the factory slightly out of spec, so it would be ideal to have your frame faced. The shop Raison interviewed stated that both expensive and cheap frames seemed equally vulnerable to being out of spec (i.e. about the same proportion came in out of spec).


The chains of my bike are clicking and the gear don't work anymore I have had a bike a couple of years and I noticed that my gears broke pretty often. I bought a new one but now that one is breaking too. They are skipping and clicking and I have brought them to different bike repairers so if anyone knows what the deal is with the gears let me know.

If the gears are making noise when you're pedaling it usually is a symptom of the derailleur being out of adjustment.

Two Most Common problems:

Basic derailleur adjustment. In many cases the cable has stretched or something has caused a change in the derailleur cable tension. This is easily fixed with the derailleur cable adjustment barrel which is either on the rear derailleur, or for mountain bikes it's on the shifter body.  Here's a video which will walk you through how to make tune the shifting.

Video On Rear Derailleur Adjustment

Derailleur hanger has been bent due to an accident or the bike falling over. The hanger is where the derailleur is attached to the bike. A special tool is needed to check and/or fix the hanger.

There's other stuff which could be wrong but I'd need a better description. Pictures would also help in guiding as mountain bikes have slightly different parts so the details on how to fix will vary.


When I shift to the smallest cog, it's suddenly too loose The other day I was riding with the chain on the smallest cog in the back (and the middle chainring in the front) and suddenly something felt like it slipped and the chain was suddenly way too loose. It felt almost like the chain had fallen off, but it hadn't.

I realized that as long as I stay in the next-to-smallest cog in the back, or any other cog actually, things are totally fine. But as soon as I get it to shift to the smallest cog (which doesn't happen all the time, but that's another problem entirely), again it's like I'm suddenly in the lowest gear possible.

In that smallest cog, as I make a full rotation, about half is totally loose, and the other half feels a bit more normal, only to return to being way too loose again.

Sorry if this makes no sense--I'm happy to clarify. I can't seem to see what's causing this problem at all. If I get off my bike and turn the pedals myself in the smallest cog, it looks and feels totally normal.

Thanks for your help.

Check your cassette is on properly. The smallest rear sprocket spinning around sounds like it is not on the freehub and spinning freely between the frame and the freehub.

There is a lockring on the outermost of the cassette which fastens the cassette to the freehub on the wheel. The cassette has notches machined out of it to match the freehub body and allow engagement.

If the lockring comes loose - the smallest cog may pop-off the freehub and not be engaged at all. You should be able to see this but you will also have a wobbling cassette.


Shimano Thumb Shifter button question I inherited an old early 1990s Schwinn CrossFit with Shimano Thumb Shifters like in the photo below. There is a tiny black button that sticks out of the side of the shifter's circle. What is it for and how do I use it?

It's a knob that allows you to switch the shifter between SIS mode and friction mode. I discovered that here where they have images of the user manual for this shifter or a similar one:

SIS stands for Shimano Indexed Shifting, which is the type of shifting most riders of newer bikes are familiar with - clicking between gears by number. Friction shifting means the lever moves smoothly and you learn to find the correct gear by feel. If you've ever ridden an older road bike (the kind that often has downtube shifters), you've probably experienced those.

As always, Sheldon has more info.


Looking for recommendation of disc brake to replace Formula RX I have a relatively old hardtail MTB installed with Formula RX brake system and rotors SM-RT53 (160mm) / SM-RT53M (180mm). Now I have to replace the brake system and would like to have some advice.
To be honest I am overwhelmed by the huge amount of product selections. Could anyone give me some direction or specific recommendation?
It was OK with the Formula RX performance, and I would like to have something with similar price/performance classes.
However, robustness of brake system is more important for me than brake performance. I ride just tour on not really challenging trails, prefer ascending than downhill, and I may have trailers with a kid. And I would probably at first keep both SM-RT53(M) unchanged.
Are 4-pistons necessary? or if my rotors are suitable for those?

Choose a brake system from a top manufacturer. Sram, Shimano, Hope, Magura etc.
Judge the pricing that fits your budget and check availability.
See if reviews exist for the brakes you like.
All the top manufacturers have excellent reliability and serviceability now.
Your rotors should be fine if not too worn, they are standard sizes.


Is the term "24 inch gear" universal (in the context of fixies)? Recently the group I ride with has included more fixie riders than I'm used to, and there's a phrase which was initially puzzling but makes perfect sense: the 24-inch gear.  I've hidden the meaning under a spoiler so readers get the experience I did.

   24 inches is two feet, i.e. walking. (we have lots of hills, some quite steep)

I think we're all familiar with the term "gear inches" to describe the equivalent diameter of a directly driven wheel - this question is specifically about the 24" gear (not low gears in general as you'll see if you look at the spoiler).

Other experienced riders, including those with fixed-gear experience hadn't come across it, and it doesn't seem common on the web (most hits are UK long-distance riders like the ones I ride with, but there are lots of sales of bikes with gears and 24" frames to bury the hits).  Is this a universal term, or localised?

"Gear inches" is universal enough to have a Wikipedia page:

Gear inches is one of several relative measures of bicycle gearing, giving an indication of the mechanical advantage of different gears. Values for 'gear inches' typically range from 20 (very low gearing) via 70 (medium gearing) to 125 (very high gearing); as in a car, low gearing is for going up hills and high gearing is for going fast.
'Gear inches' is actually the diameter in inches of the drive wheel of a penny-farthing bicycle with equivalent gearing.


Does a seatpost affect the rigidity of the frame? Is it possible to use a zero offset seatpost to make the bike frame more rigid?

I consider the Crank Brothers Cobalt 1 Straight Seatpost.

Seatpost setback is used to get the saddle in the right place to get proper rider fit on the bike. The amount of setback required is dictated by the desired riding position, the seat tube angle and the bottom bracket to saddle distance.

If you switch out a seatpost that has some setback for one without you are either going to mess up your riding position or be forced to mount your saddle to far rearward in the rail clamps.


Chain falls off my wife's E bike Is there a chain keeper or chain guide available for a single sprocket E bike type frame bike to stop chain from coming of the front single sprocket?

If your chain is coming off of the single front sprocket, you probably need to tighten the chain or get a new chain.

Use a chain checker to see if your chain is stretched out and needs to be replaced. If not, some bike frames have a longer space instead of just a single hole where the back wheel can move a bit. Just loosen the back wheel and see if it can move back a bit and tighten it in place. But I'd doubt an e-bike would have that kind of variability.

If none of that works, you may need to ask the bike shop to look it over. There may be many other reasons this is happening.


Paint bicycle keeping stickers I  have seen a used bicycle for me to buy, which has got me mainly interested, but I don't like the fact it is white. Is it possible to paint it another color keeping the stickers?

Thanks.

To repaint metal, you'll have to strip the current coating. This means you'll have to remove the stickers as well. It is unreasonable to attempt to reuse them, just as it would be silly (or at least ungodly expensive) to try to move a printed image from one T-shirt to another.
You can, however, buy and apply new stickers, if you can find the ones you like. For Rockshox forks they are readily available in several colors. I can also see that stickers for Cube frames are also available.
You can also go with e.g. vinyl wrap applied to existing frame. It can be made to your custom design, for a price.
P.S. My rough estimations are that any sort of repainting of a used frameset is likely to cost at least as much as the bicycle itself. The paint itself may be cheap, but working time to strip the frame and to repaint it are not. Unless you have enough free time to do it yourself, are not afraid to make mistakes and have an empty ventilated garage for a week (it takes several days for several coats of paint to dry).


1996 Mongoose size 19" Crossway 650 replacement size inner tube My bicycle has a label saying  size 19"  . What is the tire size for my bicycle  and the what is the  inner tube size?

According to the Bicycle Blue Book, this thing shipped with 700c wheels and 700x38 tires.

So, you need 700x38 tires (or something similar, e.g. 700x35) and a tube which is rated for 700x38 tires (these are sold by ranges, e.g. 700x38-45 tubes).


does anyone sell bicycle trailers with brakes? I recently was involved in a wreck, because I was unable to slow my trailer. I am thinking about building a refit kit to install brakes on a trailer, but I don't want to reinvent the wheel.

I'm not aware of a commerically made one, I suspect the barrier is liability issues (and possible legal issues in some places). FWIW, the limits in Australia and New Zealand are the same as for any other vehicle, so the main restriction is that the trailer can't weigh more than the towing vehicle (note below). Other jurisdictions may have different rules.

Similar questions have been asked here before:
Hitch for a cart for braking
How to make a cargo trailer?

There are two basic ways to do this. Either have brakes on the trailer activated by a lever on the bike, or make some kind of inertia brake. Having a direct lever is very simple and intuitive for the rider, but you may find yourself limited by the length of brake cables you can buy (it's possible to buy the wire on a roll and fix the endcap yourself, but annoying).

An inertia brake is somewhat harder to build, but very effective. You need the towing arm to telescope somehow, so as the trailer pushes forward on the towing vehicle you have a small movement that you can use to apply brakes. I built a four wheel trailer that worked like this, and just used cheap V brakes on the trailer. That was sufficiently effective that I didn't bother with anything more complex. The drawbar was square tubing, with a bracket at the overlap holding one end of the brake cables.

The major caveat is that neither of those solves the real problem. Once you're sliding along the ground in front of the moving trailer, neither of those will help slow it down. In theory you could grab the brake lever and use that, but in practice you're likely to focus more on getting out from under the trailer.

My preferred solution is to use a bike with two rear wheels, either a four wheel bike or a delta trike. That way you're less likely to fall off it and you can have the trailer apply downforce between the rear wheels to help with traction.

(edit: note that the default limit is actually the unloaded mass of the towing vehicle that the total trailer mass has to be under, so most bike trailers fall well outside that limit. Here's a PDF. What saves the situation is that if the manufacturer specifies a limit that applies instead).


Do mudguards/fenders help? If so, what are the best for a fixie commuter? I ride an SE Lager fixed. I'm riding on sealed paths and roads pretty much all of my commute.

On wet days my bike picks up a lot of water and also a lot of sandy/silty residue. It coats the frame and also clogs up the chain a lot. I imagine that my chain life will be suffering because of this.

Has anyone tried running mudguards and seen what kind of a difference it makes? My fixie doesn't have a huge amount of frame clearance around the wheels so I'll need something fairly minimal. I've seen these Crud Roadracers and they look like they have good coverage.

PS: I know that putting mudguards on a fixie is sacrilege (to some people... I'm not in that camp). But I'm running it for endurance and reduced maintenance, not exactly for style.

Update: Thanks for a bunch of awesome comments. However the thing I'm really wanting to focus on is whether I'll get a significantly longer lifespan for my running gear. I have waterproofs and don't mind the mess so much, I'm just trying to reduce my maintenance load and expense. The major areas I see that might be improved is chain (and therefore cogs) and maybe the bottom bracket, if I can reduce the amount of water hitting the seat pole and running down into the bracket.

Update 2: I bought a pair of the Crud Roadracers and, wow, they make such a difference. I rode on quite a wet day, but my running gear and clothes all stayed completely dry. I'm concerned they might not be durable for a commuter, but I'm certainly sold on mudguards/fenders for now.

I have a pair of SKS Race Blades (e.g. from Wiggle). They clip on and off really easily, for washing, security or just for the long days of summer when rain is decidedly unlikely. They are reasonably small and should fit all but the tightest of clearances.

For all the reasons you mention, I use them - cleanliness of my legs, back, bag and chain - but also because I like to at least play at being a good citizen. On my commute there are lots of other cyclists. Would you prefer to ride in the wet behind someone with or without guards? So the fact I'm being nice to my fellow cyclists is a really cool side benefit.

And if you think mudguards are sacrilege then, to be honest, you're probably not going to be reading this; style-over-substance hipsters are only dimly aware of the real reasons for cycling, only doing it because they think it's cool. And while it is cool, only not for the reasons they think ...


What type of nut do I have here? I had the most bizarre experience of trying to determine what kind of nut I have.  I own a Schwinn Santis made by Pacific Bicycles.

The rear tire had a bolt and nut.

I took the nut to Home Depot and we determined that it was 3/8" diameter with a 24 thread count.  We used a tool they had to do this and I called Pacific Bicycle to confirm.

It kind of looks like this nut here except for one thing:

The width is not 9/16".

I tried a 9/16 and it was too small.  I tried a 10/16 and it was too big.  I called Husky and they told me they don't make a 19/32 with would have been about the right size.

What did end up working was a 15mm.

What I find confusing is the threading is using english units while the tool part is using metric units.

This is not a problem, I could just use an adjustable wrench, but more of a curiosity question.

Has anyone else seen something like this?  Why would they do this?

I do need to get a high quality caliper that can measure to this level of smallness.

You need a 3/8"x26tpi (threads per inch) axle nut. For decades they've all had 15mm wrench flats. (I believe that is something where you can find other examples in very old American, British, and probably other inch country bikes, but that is here nor there.) Bike shops have them.

3/8x24 is usually only for internally geared and coaster brake axles. Mismatching 24 and 26 tpi in either direction tends to go on with force but is likely to damage the axle threads and/or not hold well.

As for how it came to be that one of the most common types of axle nut has imperial threads and metric flats, there are a lot of other examples with bikes of the same thing. I don't know the story in this case and I wonder if anyone alive knows definitively, but factors can include costs for changing tooling at factories, consideration to what tools are in use where. For whatever reason, 15mm has been the nearly universal standard for axle nut wrench flats for a very long time, and that sort of thing has a way of being self-perpetuating because everyone's tooled for it. Meanwhile there's always clearly been some kind of economic draw to the big Asian producers of strictly OEM-level hubs staying with 3/8 axles and not switching to M10x1, a very functionally similar size that many higher quality hubs use. I don't know exactly what that is on the micro level, but on the macro you can bet it's just another example of the bike industry always running under-capitalized and barely in the black if at all. Regardless of what created the initial circumstances, if it's not causing huge problems and it's not going to be a selling point, there's not much impetus to change things just for rationality's sake.


What tools on a multi-tool do I actually need? I feel like there are almost as many bike multi-tools out there as there are bikers. In a single trip to REI, I found nine different bike tools each ranging from only four to over thirty individual tools! But how many of these tools do I actually need?

I feel like some of the tools included in these multi-tools aren't really ever going to be necessary in the middle of a ride, but are actually better suited for at-home repair.

So, what tools do you actually need to carry with you, that you might actually need while out riding, and what tools are you can safely leave at home?

Minimally, you want to be able to tighten all of the bolts on your bike (likely a few hex keys will do this) and an appropriate screwdriver for adjusting derailer & brake pulls.  Separate from a multi-tool, a pair of tire levers are the other tool you should carry with you.

I would add a chain tool to the above list after being left in a state where I would have been much happier were I so equipped.  For that reason, I bought a Crank Brothers Multi Tool 17 which features the requisite hex keys, screwdrivers, and a chain tool, in package that is smaller & lighter than most Leatherman tools.  Some of the hex key sizes don't fit anything on my bike, but it's nice to have a set that can help most other riders.


Changing the rear wheel offset to allow space for freewheel I've had some new wheels built for a steel frame with a 126mm rear dropout spacing. The rear hub takes a 7 speed screw-on freewheel. At the moment the rim sits perfectly central to the chainstays when the axle is pushed to the back of the horizontal dropouts on both sides. However, I've discovered that there isn't enough room for the chain on the highest (14 tooth) gear because it is too close to the chainstays.

What would be the consequence of adjusting the wheel away from the frame on the drive side (about 3mm should do it) by adding washers on the drive side and removing them on the opposite side of the axle?

Could offsetting the wheel in this way affect braking? Is it likely to be detrimental to the chainline? Would it be advisable to use adjustment screws in the dropouts to make sure the front edge of the rear rim continues to be centred between the chainstays?

Any advice would be much appreciated!

Random interference with the chainstays/seatstays/dropouts like this just happens sometimes. It's not really anyone's fault.

If you added 3mm of spacer to the drive side and took 3mm away from the non-drive side, the wheel will be out of dish. That's fixable, at the expense of increasing the left-to-right spoke tension disparity, creating less total tension and a weaker wheel. (A nice new handbuilt wheel with a modern rim will already have the drive-side spokes at the highest tension the rim can take without risking cracking at the spoke holes, so the only place you can go here is reducing tension on the left side, so less total tension). The chainline will be affected but it's not likely to matter. You'll also have increased the unsupported span of drive-side axle, which is already borderline too much for some riders on 7-speed freewheel hubs, although that depends on you and your style.

Adding an equal amount of spacer on both sides, putting in a longer axle, and spreading the frame is likely a better approach then re-dishing the wheel. It negates all of the above downsides other than the unsupported axle part. It's always technically possible for bad things to happen as a result of spreading the frame, but for the most part this fear is an invention of people who aren't aware of the level of cold-setting punishment steel bikes receive when they're built. In actual practice, steel frames can be spread and aligned with almost total impunity.

A lot of nice 7-speed freewheels were made with 12-tooth small cogs. If that bought you the clearance you need and you could also get the gearing you need, that route sounds like the best one to me. It does mean being reliant on vintage drivetrain parts, which isn't ideal, but old freewheel cogs kind of last forever anyway so I wouldn't sweat it here.

Crimping/indenting the stay can also be a totally reasonable solution depending on what part of it is interfering and how much you'd need to do it by. Many, many bikes are made with partially flattened stays to help with clearance.


What kind of bottom bracket fixing is this? Dismantled my bike to try and take a look at the crank bearing, as I fear it may be getting dry. Unfortunately at the stage pictured I could go no further.

The outer and inner rings appear to be separate, and locked against each other (presumably to set the end-float of the axle?). No idea what kind of fixing this is, so also no idea what sort of tool is required.

Does anyone recognise it?

Thanks!

That's the chain guard bracket and it would likely come off with a bottom bracket lockring tool. The fixed cup of the bottom bracket should be behind it.


Unlock cleat from clipless pedal I bought this week my first clipless pedals (Shimano A530) as well as some shoes to go with it. After installing one cleat on one shoe, I "locked" the shoe on the pedal, but I do not manage to "unlock". The problem is that I did not tighten enough the cleat to the shoe (thinking that I'd do it afterwards to adjust the position of the clear), meaning that when I try to unlock, the cleat also moves.

Does anyone has an idea of I could unlock the cleat from the pedal without damaging anything?

I removed the insole of the shoe, placed the Allen wrench in the hole left by the loosened bolt. I then aligned it with the hole the bolt goes in to the cleat AND THEN turned the shoe and it popped off...


Exercises to do while cycling? Sometimes when I am cycling I will try to do some stretching to alleviate some backpain. Usually I arch my back, or push into the pedal and straighten my leg and stretch.

Does anyone do something similar? If so, can you share the stretches, exercises you do?

Thanks in advance.

You shouldn't experience pain on a well-fit bike. If you are finding that you have a lot of pain while cycling, you probably have one of two problems:

Your bike doesn't fit right. Back pain probably indicates that the distance to your handlebars is too long.
You didn't stretch well enough before hand or have aggravated an existing injury. You should probably get off the bike and relax a bit. Maybe talk to a doctor.


Pannier rack restricting dérailleur movements I fitted a pannier rack to my bike and the placement of it caused the rear derailluer cable and housing to be pushed outwards slightly, increasing the tension in the cable, I guess. The derailleur will move between 7 of 8 gears however the cable is now too taught to get the derailleur moving to the biggest gear. It is also tough to get the derailleur moving between gears without skipping them. I've tried replacing the gear cable only. The cable housing has remained the same length. Would increasing the cable housing length help or is this simply a case of the pannier being incompatible with my bike?

I would concur that the solution here is to increase the length of the cable housing that is inferring with the rack. If the rack is putting any pressure on the cable housing, then it will interfere with the ability of the derailleur to shift properly. Depending on how much free cable is left over coming out of the derailleur, You will most likely need to also replace the cable with a new one that is longer.  But this shouldn't cost any more than $10~$20 from the local bike mechanic at the back of your favorite bike shop.


What parts do I need to upgrade my drivetrain? I have a Cannondale M300 with a 7-speed drivetrain.  The parts are fairly worn and I am considering converting to a 9-speed as 7-speed components are getting harder to find.

What parts do I need to consider to replace the drive-train?

Without knowing the specifics of your setup, you may need to replace:

Chain
Front Shifter
Rear Derailleur
Cassette Hub
Cassette

You may also have to change your dropout spacing, and may need to re-dish the wheel to maintain proper alignment.


Would a MTB frame be too long if fitted with drop handlebars to build an adventure bike? I would like use a MTB frame to build an adventure bike, for the following reasons:

Use disc brakes
use wider tyres
avoid a using a gravel/cyclocross bike/frame because doesn't allow wide tyres and they are expensive

I am worried about the fact that a MTB frame is quite longer than a road bike and a cyclocross bike, and so the top tube will be long and with stem and dropbars will be too stretched and so uncomfortable over a long day on the saddle.

Would these factors make an adventure bike on a MTB frame too long, and so too difficult to ride over long distances? Or are there other considerations?

How long is a piece of string?

Any bicycle is possible, which is the beauty of a bicycle in general. Bicycles can be anything really - roadies, MTB, single-speed, recumbents, even giant A-frame types that have steps to get to the saddle!
Your question is very theoretical and will require a proper re-write because you're not being specific to a particular bicycle or size that we could say ok.. here's what you need.

As an "answer", all I can say now is that you take your frame and your new build to a competent bike fitter and get fitted for the bike! You may find all that geometry might have to be thrown out the window for the sake of your posture, back and skeletal health.

Good luck!


Why am I slow on flat surfaces? I've been riding about 300 miles a week for the last 2 years. I'm not riding in races, just riding with friends. I always ride 60+ miles (95+ km), and I'm in excellent shape. I have a low end road bike. When riding up hills or in strong head winds I am very fast. But when I ride on flat surfaces I can't seem to keep up. I'm wondering if it's the bike or my riding style.

The key to understanding your situation is its unusual nature. Speed on hills is mostly determined by power-to-weight, while speed on the flat is mostly determined by power-to-aerodynamic drag. The problem is that speed in head winds is also mostly determined by power-to-aero drag, so the conundrum is why you're good in head winds but not on the flat under calmer conditions.

If this is truly your problem, the answer is more likely to be the numerator (i.e, power) than the denominator (aero drag). Some riders tend to have more difficulty managing power on the flat than climbing; this is thought to be related to crank inertial load. Crank inertial load (CIL) can be thought of as related to "how much momentum is maintained with each pedal stroke" and varies with the fourth power of gear ratio, so when you're cruising along at high speed on a flat road your CIL is high while when you're climbing a steep hill in a low gear your CIL is relatively low. When you're climbing a steep hill you slow down a lot if you don't keep pedaling pretty steadily while if you're on the flat you can vary cadence or pedal force (within reasonable limits) without much change in speed. The "feedback" you get from the cranks with momentum is the crank inertial load. Many riders appear to modulate their cadence in response to CIL, even at the same power. The last piece of information we need to address the puzzle is that in head winds, people will often gear down lower than they ordinarily would for a given gradient under calm winds.

So, if you appear to do well in climbing and in head winds but not so well on the flat, this indicates that your power production appears to be relatively high under low CIL conditions but not so high under high CIL conditions. If you've ridden much with a power meter you would likely observe that your power is higher and steadier on hillclimbs than on the flat; more than that, you would probably observe that you have difficulty holding high power on modest descents.

There is some evidence that muscle fiber type influences freely chosen cadence so it may be the case that your muscle type is especially canted in one direction that favors power production under low CIL.


Exertion time vs heart rate or %LT(Lactate Threshold)? Are there any tables out there that show how long a person can exert themselves at a given heart rate or %LT (assuming adequate fueling)?

events lasting up to(LT = 185):

3 hours: 170+
4 hours: 165
6 hours: 150
???
IM: 130?

Source - Metabolic Factors Limiting Performance in Marathon Runners

(While the above paper is aimed at marathon runners, I'm not aware of any reason it can't be applied to other endurance sports such as long-distance cycling.)

Exercise is fuelled by a combination of fat (plasma free fatty acids plus muscle triglycerides) and carbohydrate (plasma glucose plus muscle glycogen). The proportions used vary depending on the intensity of the exercise.

Exercise at a particular intensity can be maintained until you run out of carbohydrate - "hitting the wall" or "bonking". Intensity is expressed as a % of VO2max, which can be estimated from heart rate.

In order to work out how much carbohydrate you have available, you need to estimate how much glycogen you can store in your leg muscles, how much glycogen you can store in your liver and how much carbohydrate you can take on as food (gels, sports drinks, etc) during exercise. The methods section of the paper goes into this in detail.

In order to apply this practically to cycling you should take measurements of the power you can produce at various intensities (heart rates). If you don't have the equipment to measure power, then measure speed on a flat course and estimate the power from that.

Having done all that you should be able to calculate the total energy required for a particular distance at a particular speed and what proportion of that energy will come from carbohydrate. You also have an estimate of how much carbohydrate you have available and that will tell you if you're likely to hit the wall / bonk.


Are freewheels and cassettes interchangeable? My bike is rather old and needs lots of work. I am trying to understand how to replace things myself slowly other than through a professional (to save bit money).

A bike company said that I need a new cassette now (I agree), so I bought a cassette removal tool and removed it now.

On Amazon, seems a 7 speed freewheel is much cheaper than a 7 speed cassette. I am fairly confident that my current one is cassette, and just wondering if I have to buy a cassette or for the new one I can go for a freewheel? Will it be much more extra work for people without much experience?

many thanks

No, freewheels are completely different from the cassette / free hub system and are not interchangeable.

A freewheel includes the ratchet mechanism that allows the sprockets to rotate backwards as well as the sprockets themselves, and threads into the hub.

In the cassette / free hub system the ratchet mechanism is built into the hub, and the sprockets slide onto a splined brarrel shaped ‘free hub body’.


8spd to 11spd upgrade So I am upgrading my Trek 1.1 (2016) from 8speed Shimano Claris to an assortment of Shimano Ultegra 6800, 105 5800. I just bought a 11speed cassette to complete the major parts (it hasn't shipped yet). Will I also have to buy a larger free hub assembly so that the new cassette will fit? I've never measured the difference so I'm not sure if its necessary.

As can you see here, for every increase in cog numbers there is also a increase in freehub width. So yeah, you will have to find another hub or freehub body. Changing only the freehub assembly depends on the model you have, but in general it is possible. Since your bike is kinda lower end (no offense), I would say you should do the math to see if it is actually worth it, instead of simply buying a new, better hub.


Should I change my chain? It broke once, but its condition seems rather good Expanding a bit on the title, I ride a 27.5" KTM Peak XT with a 3x10 setup. The chain I'm currently using is of unknown provenience (it was already there when I bought the bike, and it wasn't new). It's been almost one full year with me, probably around 6-7 months with the previous owner and it was never changed.

The chain broke once, but I replaced the broken link with a quick release link and it worked well from that point on. I'm always carrying a QR link with me since that day, in case bad things happen while on track.

Having this said, I am wondering whether or not I should replace my chain ASAP or it's just a normal thing for chains to be reliable for this long.

Also, how often should this (change the chain) happen?

Thanks!

The tool to check for "chain stretch" is incredibly cheap -- something every halfway-serious cyclist should have.

And chain breakage is most often caused by poorly executed shifting under load or a poorly adjusted derailer. (Though another cause is a poorly joined chain.)

(Poor lubrication is unlikely to cause the chain to break as a first indication -- excessive wear of chain and cogs is far more likely, and the chain will only break when wear has reached extreme levels.)


How do I test ride a bike that I'm looking at buying? There are questions telling me what to look for in a new bike or a second hand one, and things to look for during my test ride, but nothing about what I should actually do during my test ride. That last question has been updated to say "What should I actually do on the test drive?" but the answers don't really address that.

I assume I need to make sure the brakes and gears etc all work, but how do I do that? Just change into each gear, or do so while pedaling hard? Should that even work? Is braking hard enough to lift the rear wheel a legitimate test? Is it reasonable to (say) ride each bike round the same 10 minute circuit as fast as I can to see which ones feel best at speed (assume I'm buying a fast road bike)?

What should I do for a 5-10 minute test ride on each bike I look at? What about a quick 30 seconds in a car park if that's all I can get?

30 seconds in the parking lot: Do you feel comfortable on the bike. Does it fit you (and not completely just "bike fit"...do you like it...dig it...get it). That's what I would spend the first thirty seconds on.

Medium ride: How does it respond and do you like that response. I personally like my road bikes to be a bit "quick and twitchy" but I know a lot of folks that feel like the bike is going to do something on it's own...they want a bike that is a bit more relaxed. Several factors go into this, geometry, materials, components, etc, so best way to see if it matches what you want is to ride it.

Longer Ride: Start with mellow flat if you can to just get a feel for the bike and to warm up a bit. Then pick things up, but this is a test ride, not a race, go 70-80% but keep a bit in reserve...you don't know this bike completely yet. How does it react when you really put some power to the cranks? Do you like how it handles in a bit of a descent? How does it feel in a climb?

I would also check the brakes, drivetrain, etc...but this would actually be lower on my list. The "check the gears and the brakes", for me, is more about safety...if it doesn't shift well and has at least minimally okay components, I (or my LBS) can get it shifting nicely. Same idea with the brakes.

If it's a used bike you'll want to do a safety check BEFORE a test ride.

Good luck on finding the perfect bike...Happy Riding.


Bike trying to jumps gears when I stand My 2014 Norco storm 9.2 has a problem - whenever I am in a higher gear and standing up it tends to click and try to jump gears.

When I am sitting down it does not do this. It only happens when I stand.

Do you have any suggestions to help me?

I presume you mean the rear derailleur jumps to a higher (harder to pedal) gear when you stand up to pedal hard, right?   This is a common rear derailleur problem, happens only  under high chain tensions, and more likely with inexpensive or worn rear derailleurs.  It shouldn't do that, as it can be dangerous to the rider.  So you need to get it fixed.    Your rear derailleur either needs an adjustment, or a replacement spring,  or you need to replace it with a new or better one.


What is the practical advantage of disk brakes over rim brakes? Disk brakes are becomming more popular on bikes now, and I was just wondering what the advantage is of this type of brake over the older rim brakes.

Working backwards from how it works:

Not using the rim means the brake is unaffected by how straight the rim is, and heating the rotor doesn't affect the tyre. The rim is not worn away by braking and the rotor material can be selected entirely for its suitability for that one purpose. This also allows smaller clearance between pads and rotor, allowing:

Increased pressure between brake pad and rotor compared to rim brakes means disks are less affected by water or other contaminants. Pads can be made of harder material giving increased pad lifetime.

Having the brake caliper further away from the tyre means it's less affected by mud, and it can be made partly or fully enclosed to further sheild it. The rotor is also less likely to  hit obstacles as it's further from the ground.

Being a hub brake makes unconventional designs possible. Single sided wheel mounts are the most obvious example, but some suspension systems are incompatible with rim brakes, and building a rim braked carbon composite wheel is much harder than building one to use a hub brake.

Disk brakes can also be fitted to both sides of a wheel for increased heat dissipation, and it's easier to vary the design for different characteristics (weight, heat capacity, modulation etc). Doing that with a rim brake means the brake manufacturer has to start selling wheels as well.

These combine to make disk brakes more reliable and easier to maintain.It's also somewhat easier to remove and reinstall wheels as you don't have to release the brake first.


Can I put drop handlebars on my commuter bike? I want to put drop handlebars on my commuter bike which has a straight bar. The guy at the bike store said that drop handlebars are too thick to fit my standard brake/shift system.

I don't want to change my braking/shifting system. Can i modify my brake levers to increase the diameter so they can fit on dropped handlebars?

It's very unlikely that your brake levers can be modified to increase the diameter enough to handle the change from 22.2mm to 23.8mm.  The brake clamps just aren't adjustable like that, typically.

Where on the handlebars were you thinking to mount the brake levers? If you were thinking at the middle (next to the stem), then you're likely in the area where the handlebar is wider (the "clamp diameter") which is even worse.

One option is going with "trekking" (aka "butterfly") handlebars. These are typically the same diameter as straight bars and can easily accomodate the same brake/shift levers.  They look a little funny, but do give you more handlebar positions similar to what drop bars do.

Or just add bar ends to your existing bars. The right bar ends can give you a comfortable sideways hand position similar to the main hand position people use on drop bars.

Another thing to consider is handlebar positions on the drop bars.  Typically the position people use most often is on the brake hoods. Brake levers made for drop bars tend to have comfortably shaped hoods with a little bit of give in them. Brake levers made for flat handlebars don't generally have a comfortable place to rest your hand.

If you do decide to switch your brake levers, be aware that the amount of pull is likely different so you'll either have to be careful with which brakes you get or do something to accomodate the difference.

Here's a nice article that includes more details about changing to drop bars: http://sheldonbrown.com/deakins/handlebars.html


Why am I breaking a ridiculous number of spokes? First, this is a follow up to this:
Why does my back wheel keep becoming untrue?

(The short version is I bought a used bike a few weeks ago, I broke a spoke on the back wheel, replaced the spoke, trued the wheel with a tensiometer, and found that it had become untrue again. The diagnosis was either the wheel was bent, or that the spokes were just settling and re-truing it would sort out the problem.)

I've been riding it over a week with an untrue back wheel (aka Kayak Mode). Today, I checked the wheel because the trouble had become a big issue again, and found I had two (!) broken spokes since replacing the first broken one a week or two ago.

So, why are my spokes snapping like spaghetti? I guess:

Because I was riding without truing the wheel
Because I'm riding too hard (i.e. coming off curbs)
Some combination of the two, or something else.

Thanks!

Your pal,
JKD

POSTSCRIPT
July 28, 2011

First, thanks everybody.

I wanted to follow up for people who find this question later, and describe the rest of my experience with the wheel.

I kept breaking spokes after replacing them, and by the time I got to the shop again, I had broken five (!) more. They looked at it, I looked at it, and I ended up replacing the wheel. It rides fine now, and as far as I can tell, it was just an old wheel.

Kazah!

Generally, repeated issues with broken spokes indicates either damage to the rim, meaning that the metal hoop of the rim is physically bent while under no tension, or that the spokes are at the end of their fatigue life.
Any wheel has an expected use life, and usually, you will wear a track in the aluminum rim from braking forces before the fatigue life of the stainless steel spoke becomes an issue. However, if the rim is damaged, as referenced in your previous question, then the tension of the wheel cannot be evenly consistent, because some spokes must be tighter than others in order to hold the rim true and straight. If our wheel is unevenly tensioned, it allows a far greater amount of movement of each spoke during the revolution of a wheel, and this stresses the spokes beyond their designed strength. And you break more spokes.
If the rim is not bent, the same issue applies, except it is smaller movement of the spokes over a far greater period of time which has pushed the spoke beyond its useful life.


Best way to train in an area with many hills I recently bought a bicycle, mostly for exercise and fun. I am not fat, but I am really out of shape, I get tired quickly and cannot stand very long rides.

I know riding a bike constantly will reduce this, but the area I live are not very plain, which I would consider better. Most of the time I'm going (slightly) uphill or downhill; I'd like my bike rides to be "smoother" than this.

Is there a way to optimize my ride, so I can get the most of it?

I have a cheap road bike. It has only 12 gears, but except for steep hills, the gears are ok.

You can climb a hill basically three different ways:

Spinning up the hill in low gear at high RPM
Charging up the hill standing up (or at least really pumping the muscles sitting)
Grinding up the hill at 20-30 RPM

Of those, the third one is a good way to wreck your knees and generally make yourself miserable.  The other two, however, are both perfectly acceptable.

Basically, you divide hills into those that are short enough you can comfortably "charge" up, and those that are longer and more challenging.

For the short ones (and "short" is purely a personal choice) you typically downshift a bit and then raise your exertion level to something near your comfortable maximum, probably dropping your RPM a little but maintaining at least 60 RPM.

For the longer hills (and maybe a few shorter ones at the end of a long day) you downshift a fair bit more, raise your exertion level only a little, and "spin" at roughly the same RPM you'd use on level ground (though truth be told mine always falls off a bit), adjusting gears up/down to maintain that RPM and exertion level.

The thing you want to do is to use your gears to maintain the "sweet spot" where you're holding a relatively steady RPM (somewhere between 60 and 90) and also maintaining an exertion level that you can sustain for the long haul.

Of course, if your bike doesn't have a broad enough gear range to "spin" up longer hills then you have a problem.  You can try "charging", but that can run you ragged pretty quickly.  So (since you should NOT "grind" up the hill) you probably need to figure a different route that is more suitable to your bike and fitness level.

One basic rule of thumb I use while cycling that seems to work out pretty well is to always pedal faster than I breathe.  That is, if my respiration rate is 60 then I should be pedaling at least 70-80 RPM.  If I notice my RPM falling off or my respiration rate climbing, I downshift until my respiration rate drops a bit.  And on the flat I aim for an RPM that's twice my respiration rate.


Disc brake maintenance For some days now I am observing the decreasing performance of my disc brakes on my MTB. Additionally, braking is extremely loud (squeaking). I don't think I have oil or fatty substances on the discs. Still I can't exclude that.

So what do you think is the problem and how can I solve it?

I would guess I have to change the brakeshoes but I am not sure.

How can I check the actual problem without wasting time/money?
If I have to apply new brakeshoes, how is this done safely?

My brakes are hydraulic: Shimano Deore BR-M596.

There are a number of simple things you can do to try improve performance before replacing the brake pads.

Check the pads to see how worn they are. Here is an example of a new and worn pad requiring replacing.

If the pads don't appear to need replacing you can:

Lightly sand the pad with fine sand paper
Clean the rotor with isopropyl alcohol (or any non-residue solvent)

If that eliminates the squeaking but doesn't improve performance the next step is to bleed brakes. If you have Avid similar brakes the process (similar for Juicy and Elixirs) is more involved than the Shimano process and make require professional assistance.


Do SunTour freewheels have uneven cog spacing? I have a Suntour freewheel (6 spd, "Perfect" model) that has unequal spacer widths. The spacer between the top and bottom 3 speeds is wider than the other 4 spacers. I purchased the bike used ('80-'81 Colnago Super), and I know the wheels (hubs and rims) are not original, but the freewheel (the body anyways) is of the correct time period. I noticed that the cogs do not have beveled teeth; I thought all SunTour FWs of that era had bevelled teeth to help transitioning from higher to lower gears. Teeth on cogs (excepting the smallest) have little or no wear (front 52T ring is unworn,44T ring shows wear); I assume previous owner rode the small ring in both the front and rear, rarely shifting. Bike is in excellent condition for 40 years old.

Freewheels normally had uneven spacing between gears back back then. Until indexed shifting became popular starting in the mid-80s, there was no need for spacing to be consistent. The outer sprockets were threaded on, and the inner ones were splined, so they weren't even attached in the same way. (Aside: I recall a bike shop had threaded together a "9-speed" freewheel and stuck it in their display case as a joke—It was much too wide to mount on a bike. Simpler times.)
I don't remember sprockets having fancy tooth profiles back then: that's an an even newer development to improve shifting.


Does dropping off a 4" kerb damage wheels? Every day I ride off a kerb from the pavement onto the road (about a 4" drop) on a pretty standard commuter bike with 26" tires. (I could get off, or ride around, but it's a pain…)

Is this a good idea? Is it going to damage the tire or wheel?
If I am going to do this, is there a way of doing it to minimise any problems it might cause? (e.g. riding faster/slower, applying brakes/not applying brakes.)

I'm hoping the details won't make much difference, but just in case, I'm 85kg/185lb, the tires are 1.15" wide, and going by the price of the bike (~$800), the wheels are average commuter quality.

Riding off a curb is not necessarily going to damage the wheel or tire. I do this pretty frequently on my road bike with narrow 23mm tires with no issues.

However, if you are a heavy rider, have cheap wheels, have under inflated tires  or use poor technique you could run into problems. If you can feel the rim hitting the ground then definitely don't do it.

Good technique is to approach reasonably slowly, stand up on the pedals and bend knees and elbows, shift you weight back onto the rear wheel as the front wheel goes over, the shift weight forward onto the front wheel as the rear wheel goes over. you can probably find some instructional YouTube videos easily.

If you have been doing this for a while and there are no obvious problems with your wheels, chances are they are fine. Check that the rims are true by spinning the wheel and watching the passage of the rim near a fixed point near the rim - brake pads for instance. Check the spoke tension by pinching pairs of spokes. If the rim is untrue or you have loose spokes get a local bike shop to true them up.


Help identifying this chainring where can find online a chainring with fittings like this?

I believe the central spline pattern is proprietary to the X-Flow crank. Basically you will not be able to get a single aftermarket chainring to fit.

If you want to go 1x10, you cheapest option is to get a used 3x crank that fits your bottom bracket bearing, ditch the rings and install a narrow-wide ring in the middle position.