What is the purpose of whipping a bike? What is the purpose of "whipping" a mountain bike during a jump? Is it merely a trick (show off) or is it a functional move with a purpose? It is very commonly seen in videos which made me wonder if there is a useful function to it.

By "whipping" I mean the motion you can see during jumping in the 30 or so seconds starting here:

A screenshot from the video:

Spinning wheels have gyroscopic effects. Whipping the bike can be a way to reposition the bike so that when it comes out of the whip, it is in an orientation that wouldn't be possible going over the jump dead-straight. This effect is large in the case of motocross.
From a BMX perspective, it is very important to land on the backside of the landing ramp with the proper bend in your legs so that you can get the maximum "pump" off the landing. In some cases, especially in the case of a short landing ramp, it can be advantageous to do a slight whip and therefore land with the bike at an angle. This can get you more pump than landing perfectly straight. If you watch people negotiate a street spine, for example, you will see that it's downright awkward to go straight over without doing a whip.
Also, there's often a corner and a berm shortly after a jump, so a slight whip can set you up for what comes next, vs. landing perfectly straight then having to muscle the upcoming corner.


Rolling backwards while pedaling forward on a Freecoaster Can anyone tell me what happens when rolling backwards while pedaling forward
on a freecoaster bike? I mean does it gradually slow it down, or does it come
to an abrupt hault? I have not tried it yet.

I think there is some confusion about the difference between a Freecoaster hub, a Freewheeling hub, and a Coaster brake hub. So briefly:

A freewheel hub is by far the most abundant and utilized piece of bicycling technology and relies on a ratchet and pawl mechanism (or similar) to engage the drivetrain while pedaling forward, but allows coasting when not pedaling. Any freewheel or cassette hub uses this technology.
A coaster brake is a type of brake that is built into the hub shell that turns backward pedal force into braking force.
A Freecoaster hub uses a clutch mechanism to engage the hub shell while pedaling forward, but disengages the hub while pedaling or coasting backward. This allows you to coast backwards without having to move your pedals. They are totally silent because there are no pawls!

Above is a hastily drawn sketch of a freecoaster hub. There are no pawls...instead is a cone shaped clutch which is threaded onto the driver body which extends over the axle. The driver cog on the left is supported on the axle by bearings on either side (there are also lots of other bits and pieces, but these are the general parts.) When pedaled forward the driver threads through the clutch and pulls it into the wedged surface of the hub. The friction between the hub and the clutch is what drives you forward. When you change directions (or pedal backwards) the driver threads the clutch to a backstop which adjusts the play from freecoasting to pedaling forward.

If you were to pedal forwards while coasting backwards, your pedal force would engage the clutch into the hub shell. -- As @Daniel R Hicks pointed out, this is pretty much the same mechanism that a coaster brake utilizes except in reverse. Pedaling forward ought to engage the clutch and slow you down. --

However...I'm not sure that I recommend that you do this because neither the clutch surface nor the hub shell are designed for slowing, only for engaging. (If anybody has more info on the actual construction of the hub shell...whether there is a steel insert to bear against and provide braking support, or whether the driver and hub shell are forward motion only, please edit away.)

Here is a fantastic video about freecoaster anatomy.


Thread diameter of hub I've got a rear hub Shimano 5353 with a freewheel,I want to change the wheel for the one with campganolo hub,I dont know whether my freewheel will suit campganolo hub

Presumably the Shimano hub/freewheel has an ISO freewheel thread and the Campy hub has a Italian thread. These thread standards are close enough to interchangeable.

From Sheldon Brown's Freewheel Page:

  Italian: 1.378" x 24 tpi / 35 x 1.058 mm

  ISO: 1.375" x 24 tpi / 34.92 x 1.058 mm


Can I use a 29er rigid front fork and still use 650b wheels (brakes are disc)? Any negative side effects? I have a Jamis Dragon 27.5 hardtail that I would like to convert to more of a gravel bike. It is hard to find a 27.5 rigid fork with a 1-1/8" non-tapered steer tube. Would there be any negative effects to using a 700c fork instead with 650b wheels? The brakes are disc (160, 140).

With disk brakes you can easily run 650B in a 29er fork.
The main consideration is maintaining the bikes geometry. You should look for a 29 fork with the offset and a crown to axle measurement as close as possible to the original.
As you are changing to no suspension travel, remove the sag from the original forks measurements (typically 20%, 25mm for a 120).   From specs the fork you have has a 504mm axle-crown, less 25mm sag, you want a 29er rigid with about 480mm axle crown. (You do need to confirm these numbers by measuring your fork.)


Dahon Folding bike, seat came right off! I was adjusting the seat on my Dahon Vitesse D8 when the seatpost quick release simply fell off (yellow piece in the images I supply)

The piece that bends to stop the seat from moving came off attached to the seatpost too.

I'm not so good at these things. No matter what combination I try there are always two issues (even when I successfully get the seat to lock in place)

The seatpost is constantly rotating (as opposed to completely locked in)
I can't pick up the bike by the seat, even though it's locked so it can't move down, it always freely comes up when I try to pick it up.

Here is a small gallery of images with my issue:

http://imgur.com/a/9xKFV

I've tried all sorts of variations and cannot get the the seatpost to lock in place properly...

Any help would be great! I've tried downloading the manual for this bike, but no where are these pieces mentioned or even an assembly guide.

Looks like there's something missing.  The golden piece should go around the top of the black piece of the frame, and should clamp it tight without the two edges touching by the threadded bolt.

The silver piece looks like a shim or a spacer of some sort, and the seat and seatpole/post has not been pictured, but would go inside the silver tube.

Is there a second seat clamp (golden piece) missing, to go around the silver bit to hold it to the seat post proper ?

Edit:-
A google suggests these have telescopic seat posts, so silver piece is not just a static shim.   The other possibility is your seat clamp may have stretched and is no longer providing enough clamping force.


What can I do to fix or replace this broken axle? I cased a jump badly and I broke either my bottom bracket or crank, I’m not sure which. What can I do to fix or replace this?

Picture is of my broken bottom bracket or crankset.

You've broken your bottom bracket's axle.
There is no way to safely reattach, so you're up for a replacement bottom bracket.  Ideally you'd install a cartridge BB that duplicates what you have.
The crank arm (in your hand)  is probably okay to reuse, though have a good clean and a close inspection before doing so.  Dings are fine, chips maybe, and cracks are not.  You need a crank puller to get the sheared-off stub out of the crank arm.
I'm not sure if your bike uses a square taper or one of the newer standards - the broken bit could be square or round.  So your new BB has to match what the cranks fit onto, otherwise you'd need new cranks too and that's getting expensive.
Tools should be mostly common hand tools (ie a big spanner), and you will need a BB tool to fit the splines visible in your photo, and a crank extractor to push the nubbin out of the crank arm.   That last might be possible using a press or a hammer and brass drift, but only because its already off the bike.

A follow-on thought - to break a bike like this means either a very hard impact or a lack of maintenance on your part.
Based on the corrosion I can see in the photo, there's a part which was already cracked and exposed to the elements for long enough for rust to start.
Upshot - there was a fairly hard impact, and this was focused on pre-existing damage that you hadn't noticed.  I'd strongly recommend a good clean and de-grease of your entire bike, and go over it looking for other looming damage.  Or ask someone else to help with this - its easy to miss things.


Relative weight of disc brakes People say (for example here) that disc brakes are relatively heavy, giving this as a reason for not using them.

How much heavier than rim brakes are disc brakes? Is the extra heaviness in the brakes, or in the stronger rims, tires, and/or forks?

The difference in weight is there, but hasn't really been significant for the last few years. Scott, for instance, is building a complete, disc brake hardtail with a 4" travel fork. Bike weight: 7.45 Kg, or roughly 16 lbs. That's 2 lbs less than my road bike.

The weight comparison only becomes truly significant when you look at more basic bicycles, i.e. the $600-1500 market, because the cost penalties for premium parts, like truly light weight disc brakes and hubs, don't allow use in that market.

If you are looking at an aftermarket upgrade, expect to spend $1500 on new wheels and brakes, and often more, for quality, lightweight kit. The weight penalty has gotten down to only 50-100 grams in most cases, between a bike built with a high quality disc setup and a high quality V-brake setup.

In my opinion, the advantage in brake modulation and power, not to mention consistency in all weather conditions far outweighs the the addition of a few grams. No pun intended.


Interpreting a frame number digit I'm trying to track down the owner of a Giant bike that I found by the roadside. The frame number on the bottom bracket looks like this:

My interpretation is GX828648, but I'm just a little bit uncertain about the penultimate digit. (The photo isn't great but it's not really easier to see in real life.) Do you agree with me that it looks like a 4?

Good luck - there's a very high probability noone noted the serial number, or registered it anywhere that you can search.  Giant themselves might be able to tell you what shop sold it, but whether they kept records or not, who knows.

Your other option is to report it to the local police station as "found property" and after a month if the owner doesn't claim it then its yours legally.  We scored a nice tent that way that blew into our yard once, fully assembled but never pegged to the ground.

You can assume its probably not repainted, so is a Blue bike from new.

I'd agree with your reading of the digits.  Possibly the first character is a C or a Q or maybe an O, but the rest look exactly right.   G for Giant might make a lot of sense too.


Is this front derailer snapped and/or bent? I'm no expert but looks no where close to how it should be.

I think a bit has snapped off?

Also looks to be no where close to the outside of the biggest gear, (even when in that gear). It should kind of encase the chain?

I'm assuming I'll need a brand new part?

Yes.  That is definitely broken, and appears to be irreparable, you will need to replace that.


New road bike: alloy dual pivot brakes work poorly I recently bought a new road bike (a very entry model - Giordano Acciao) which has alloy dual pivot brakes. The brakes seem to work poorly, even though they are quite tight. If I squeeze the brake and push the bike forward it might still move - when riding this feeling is even worse, the brake just won't fixate the wheel to non-motion. How is that possible on a new bike? Is there something I can do and that I am missing and I should do? Shouldn't the brake stop the wheel completely?

Best regards

In the USA at least you can take a bike back to the store you bought it from and ask for problems to be addressed. However I googled 'Giordano Acciao' and I'm guessing you got this bike from Amazon or a department store, so that's likely not an option for you.

no offense meant, but bikes from Amazon, Walmart or department stores are the lowest quality and can be barely be usable. The performance you are getting may just be the best the low quality components can provide.

That said there are a number of things you can try to improve things. Check the pad alignment and brake adjustment. Park Tool has a good video showing how to do that here. The pads may need a little wearing in and will improve as the outer surface wears off and the pad conforms to the rim. You can also buy higher quality pads from a dedicated bike shop.


Wear and tear and warranty I have a trek 7.1 that I bought last March (2014) and have been told that the pads, front wheel, chain and cassette need replacing. Is this normal for 4 to 5 days a week usage for commuting (5 to six miles total) then the odd longer cycle? The wheel was my fault as I damaged it by not replacing the pads.

Should this stuff be covered by warranty considering it's less then a year? I have been told it's wear and tear which isn't covered but I don't think it's reasonable I should have to make these repairs so early on (minus the wheel obviously). Just wondered if I should try and get this done under warranty or if it's a lost cause.

Many things on bicycles are consumable and anything that moves or rubs is going to have to be replaced, it's just a matter of when.
It's unusual for a cassette to wear out completely within a year although if it's been ridden on a stretched chain or without regular cleaning and lubing it'll wear out much faster.
In my experience chains are normally the first things to wear out, presumably because they almost constantly in motion and rubbing against the cogs while you ride plus picking up all kinds of stuff that flies off of the wheels. I normally replace my chains every year regardless of the state that they are in simply because of the low cost of a replacement chain and the relatively high amount of damage that running a worn chain can cause.
You can tell if the cassette (or the  chainrings) need replacing by checking the teeth. If the teeth looked ramped you should switch out the part. See Image:

If the teeth don't look worn but are black with dirt you can clean them with a de-greaser you may find it easier to clean the cassette if you remove it although this requires a cassette removal tool otherwise you can leave it on and clean it with a brush and ordinary dish soap, just rinse afterwards, dry it and remember to lube the inside of the chain again after cleaning it being careful not to overdo it as that will just cause muck and grit to stick to it while riding. Do not use WD-40!
To check the wear on your brake pads look at them from the side and check for grooves. New brake pads come with groves which allow water to escape from under them much like the tread on a tyre. If your brake pad has no visible groves on the face that touches the rim, they should be replaced.


Cyclocross Road Tire I have the following tire its a 700x35c cyclocross tyre. I am looking to use this bike on the road for a while.

What size of road tire would fit this?

Thanks

Any 700c tire narrower than 35mm that's not narrower than your rim's outside width. Typical choices would be any 700x25, 28, or 32.


Does high PSI or low PSI affect the life of a tire? Is there a method to tell the life of a tire? How can you tell if a tire is going to wear down faster than another tire? I assume puncture resistant tires wear out slowly, but I'm really curious whether I put high PSI in my tire there will be significant difference. Will high PSI raise/lower the lifespan of my tire ceteris paribus (terrain, material being the same)?

Your best bet is to operate the tire in the pressure range on the tires. Check the air pressure regularly.

Nominally if you are 180 lb or more then high number.  And 140 lb or less the low number.  In between then in between.

Higher pressure maybe a longer life but still stay in the range.  If you weigh 140 lb then not worth a higher pressure for a harsher ride to maybe get a few more miles.

Race tires naturally have the shortest life.

A soft rubber tire will wear faster but have better traction.

A hard rubber tire will last longer but also poor traction and a harsh ride.

And consider $ / mile.  You can buy a $50 tire that is probably not going to last twice as long as a $25 tire.


How do you tell what model of bike I have? I bought this bike 2 days ago. I searched for some info, but couldn't find it. The only information I found was to be around 1972

Assuming this is an Eddy Merckx, you can tell a lot about it from its serial number, which should be stamped on the underside of the bottom bracket. There are a few serial-number decoders online. Here's one. The one confounding factor is the "CR" seatstay caps. Merckxs usually (but not always) had an "EM" cap. That orange was a popular color for Merckx bikes, but usually there was a blue panel on the downtube, not seat tube, and I don't think they ever were pinstriped.


Can I find out about compatible newer models of my Shimano chainring? I have an MTB that is quite old. The biggest chainring with 42 teeth is now done and I need a new one. It's a Shimano FCMC30, but it seems nobody is selling that new anymore. The chainring in question says "Shimano Hyperdrive C".
Since I can't find the original, is there maybe a single chain ring I could buy that is compatible to my type?
If so, where would I find such information e.g. online?

si.shimano.com has Shimano's technical documentation.  Searching for your crankset FC-MC30 produces the Exploded View (EV) document https://si.shimano.com/pdfs/ev/EV-FC-MC30-1351.pdf
This lists the part numbers and descriptions of the components of the crankset. The good news is that your chainrings are bolted on and so are replaceable. A replacement ring must have the same mounting hole number and position (BCD - diameter of the circle of bolts). The bad news is that the large chainring mounting holes apparently fit a short-lived, obsolete standard that is unlikely to be found.
A recent reddit post is relevant:

semyorka7 6 months ago · edited 6 months ago
So, look closer at that diagram. STX FC-MT30 through MT33 were weird
shit - there's actually only bolts on the crank for the 58mm bolt
circle. both the inner and middle rings bolt through with the 58mm
circle, the outer ring actually attaches to the middle ring.
You can probably get away with a 94mm 5-arm outer ring, but the bigger
issue is that if you want to replace the middle ring, you need a NOS
middle ring - otherwise there's no place to attach the outer ring
Both MT32 and MT33 call out 94mm instead of 95mm for the outer ring,
so if you want to guarantee that a non-STX outer ring will bolt up
without having to do any work with a metal file, those are the ones I
would look for. Shimano PN 1SC3200
Unfortunately, people usually spend most of their time in the middle
ring and NOS middle rings for old shimano MTB cranksets are basically
unobtanium compared to outer and inner rings. Frankly I'd recommend
replacing the crankset with a nice 110/74 triple that you can easily
source a variety of chainrings for - FC-M730, FC-MT60, FC-M560,
FC-M900, etc are all plentiful on ebay.


Carbon bike specific maintainance I am about to get my first carbon bike next spring, it's a MTB with a carbon frame with some aluminium components.

What are the things I should do and should not do, to avoid damaging it by improper maintenance? I see other threads here about people having problems with stuck seatposts an other, a compilation of all this knowledge plus additional tips would be welcome.

Always - Always! Follow the instructions regarding torque - otherwise you could snap your frame/post etc..

As for everything else, I think it's the same, I treat my carbon roadie as I would my aluminium.

Clean it etc, but with carbon, if you have a crash or such, it would be an idea to check for cracks, and get them looked at!


How to clean consumable metallic parts cheaply while touring? By the term consumable metallic parts I mean things such as derailleur pulleys, chains and cassettes. I have met tourers that suggested me cooking oil for cleaning the metallic parts, more here. The irony is that this frugal question ignited the tip but I am starting to feel cooking oil is not necessarily frugal, the oil is binned at the end (loss). My answer contains a cleaning way for about 0.1-0.5EUR. So how can I clean the parts more cheaply?

Related

cooking oil used to clean chains -answer here
substitutes for chain lubricants -question here

The most frugal is not to intensively clean these parts except at the end of the tour when you overhaul your bike.

Simply brushing off the dirt with a cleaning brush, toothbrush, or rag and relubricating with a good dry lube will get you most of the benefits with little of the mess. And it’s a lighter kit.

You don’t need a spotless bike.


Pulsating and screeching after changing disc brake pads Please bear with me, as I am very new to bicycle maintenance.

I changed the brake pads in my front brake (Tektro Auriga on a Rockrider 540 bicycle), as I was unhappy with the braking performance and couldn't seem to improve it. It came with E10.11 brake pads and I changed them to P20.11 ones. (It should have come with A10.11, but that's not what I found ...) These had much better reviews on Amazon, with many people saying that the braking performance is noticeably better.

Unfortunately, now there is screeching and pulsating when using the brakes. What can I do to improve this?

I am certain that I did not contaminate the pads. I was very careful when changing them.

When changing the pads, I cleaned the rotors thoroughly with 70% propanol.

I performed the bedding-in procedure as instructed: Speed up as much as I can, then brake hard, but do not stop. Do it at least 10 times. I used some water on the brakes before bedding in, as suggested in this Park Tool video.

Strangely, if I pour some water over the brakes, then they become smoother and the screeching disappears for up to an hour. After that, everything is back to how it was.

After changing the pads, and for a second time after bedding in, I adjusted the brake calipers by loosening the screws, pulling on the brake lever and tightening the screws. The rotor looks parallel to the pads. The rotor is true, as far as I can tell.

I am quite disappointed about the outcome of this experiment in changing brake pads, and I would appreciate any advice on how to get rid of the pulsating, if not the screeching.

The only advice I could find on how to deal with this was to lightly sand the rotors, as well as the pads. I am somewhat reluctant to do that after reading that this could worsen the pulsating. I do not have the tool to remove the rotor, and I am worried that I could not do the sanding well enough while the rotor is on the wheel.

Unfortunately you have done nearly everything possible. Some brakes/forks/frame/pads/disc combination just do not work nicely.

The one remaining thing you have to change is the disk. As the pads bed in, they lay down a thin layer of pad material on the disk, it is the microscopically thin layer that allows the braking to occur. If the bedding in is done poorly, the layer is uneven, and further bedding in may not even it up. Changing pads means the material laid down on the discs may not bed in with the new pad material. Sanding the pads disrupts (I won't say removes) this microscopic layer, allowing a new layer to be laid down when bedding in again. If the new layer is laid down evenly, the brakes will not squeal.

A final option that may (or may not) work it to change the disk itself. The obvious choice is a different type, but even this is no guarantee of quite brakes.

You really have three choices - go back to you old pads (They may now squeal), tackle the disk (sand or replace) or live with it.

Use a fine (400 or even 1000 grit) wet and dry sanding paper. This can be done with the disk in place, but is easier if you remove it.  There is no guarantee this will work, new discs are sometimes the only thing you can do.


For a long (25mile each way) commute, what kind of bike should I look at? I'd really like to be able to commute to work. It's a long way though - 25 miles away. Too far for every day, but maybe I can cycle it once or twice a week.

I tried it on my old mountain bike a couple of times and it took me 2 hours each way, and I was very tired. I'm hoping a new bike might make it more do-able. I really can't decide what kind of bike to get though. My route has about 10 miles in the city, and 15 miles on country roads.

I'd like something reasonably light. Hybrids look a bit on the heavy side. Full on road-bikes look a bit too aggressive, and I don't think I'd like the drop handle-bars. Something like a more relaxed road-bike with flat bars would be good, but on digging through the web I'm having trouble finding anything that looks like that.

Can you recommend a suitable bike that would fit what I'm looking for?

I'm in the UK and could spend up to £1000 for the right thing.

I would defiantly not rush out and buy a new expensive bike.  Here are the steps you should follow:

1) Try to make your bike faster.  There are  a few ways that you can do this but I am going to make two suggestions that will be cheap and easy.

Get slick (smooth) tires.  The should put you back around $60 but should give you a good idea of what a road bike might feel like.  The difference in speed will be shocking to you.
Put some bar ends on your bike these will help you to change your body position on your ride.  (More positions = greater happiness)

2) Before you buy a "new kind of bike" (ie: road bike, hybrid, etc) make sure that you try it.  I just bought an older road bike on craig's list for $20.  The bike was in very poor condition but it allowed me to figure out what riding a road bike is like.  I upgraded a few weeks later knowing what I really wanted.

If you don't know what you want I would mess around with your bike a bit and then buy a couple throw-aways.  I bet that you could do that for $50 - $200 (not including resale revenue) but you will know what you want before you drop the big dollars.


How to clean out the inside threads of a braze-on? I'm installing a basket on my cruiser, and getting some of the allen screws into the fork braze-ons is rough going. It feels like there's dirt or grease inside the threads of the braze-ons. Forcing the screws in could damage the threads.

How can I clean out the inside threads thoroughly, using common household items?

Note: Folks installing racks and fenders will often run into the same problems. I mention it here so searches on those terms will show this question.)

I use Q-tips and a degreaser (WD40 or similar will work).  Spray on, wipe off.  Soaking helps cut hard to remove grime.


Suggestions on buying a road bike for the city I'm looking to buy a bike with which to get around Atlanta.  My budget is about $500.

I've seen lots of suggestions for a fixie but those seem relatively difficult.

I plan to ride about 5-10 miles a day.

Any help would be much appreciated!

Update:

I need a bike in order to get around as quickly as possible.  There are few hills, but pot holes and poorly paved roads are a problem.

I do not need racks or fenders.

With this budget, a used bike will get you the best bang for your buck. I was able to find a ten to fifteen year old road bike with good components (Ultegra) and an aluminum frame for around $600. A friend found a twenty to thirty year old road bike with a steel frame and downtube shifters for around $300. Both were in good condition and have high quality components, with the age of the bikes being the main sacrifice. If you're looking for a nice road bike, you can do it with your budget as long as you're willing to go used, but a new bike in this price range will just disappoint you.


Hayes Sole Disk Brake sudden loss of pressure. I braked hard today and felt the pressure in my disk brake drop very suddenly.

Since that point the brake has not been working with no action at the calliper and little  pressure in the lever but not spongy.

Any one know the likely cause and whether a bleed might fix.

I can't see any evidence of fluid leakage.

Sounds like a major fluid loss, somewhere. Check around the hose joints, and the brake levers and calipers for fluid leakage. If not, it's probably a blown piston seal, which in rare cases can leak, but reseal under low fluid pressure.


Can I replace an inner tube with a Dunlop valve with one with a Schrader valve? I've accidentally bought an inner tube with a Schrader valve for a bicycle that's currently fitted with Dunlop valves. Can I still use it or they require holes in the rim of a different size?

Answer: Yes you can.  Woods/Dunlop valves have a nominal hole size of 8mm, identical to a Schrader/Auto valve.

For completeness, a presta valve uses a 6mm hole.

Reasons not to - authenticity of an antique bike, or maybe having to carry a second pump head/fitting if both tubes have different valves.


Replace a 52/36 crankset with 50/34 I'm looking at purchasing a new bike with a 52/36 crankset on a 11-32 cassette. I've grown accustomed to a 50/34 crankset on the same cassete, and for the type of riding I do in the PNW (300-400ft hills regularly, 3000ft+ mountains monthly), I don't think I want to give up that lowest gear. It's not that I always rely on the lowest gear, it's just that want the option for days where I want to take it easy. I've been riding around on my current bike where I avoid using the lowest gear to simulate the 52/36 crankset and I've found that after a long day of riding I really like the option of spinning up a steeper hill.

So, I know I can swap out the crankset but will I have to swap out more than that? The 52/36 crankset is really the only thing keeping me from purchasing this new bike over something else that comes with a 50/34 crankset.

For the complete specs, this Canyon is what I'm currently considering.

You should not have to replace the entire crank-set. In general, a 'mid-compact' 52/36 crank will have a 110mm BCD spider, which allows 50 and 34 tooth rings to be installed.

The Ultegra FC-R8000 crank on the Canyon comes in 53-39, 52-36 and 50-34 versions, so you will be able to get the smaller rings for that specific crank.

The front derailleur may need to be dropped down slightly to adjust for the slightly smaller rings.

Front derailleurs have a 'max capacity' spec which is the difference in tooth counts between the rings - typically 16 for a road group-set. Obviously this is not changed between 52/36 and 50/34 so the derailleur does not have to be replaced.

Updates:

As mentioned in comments the chain may need shortening.

You might need to remove the crank to get the small ring off, but no special tools are required with Shimano 2-piece cranks - just a couple of bolts on the non-drive side arm.


What tool should I purchase in order to replace the bottom bracket in my Giant Defy 3? I'm changing my front crankset from Gossamer FSA 105 to Shimano 105 FC-R7000 in my Giant Defy 3 road bike from 2015...

I kinda stuck on removing the bottom bracket as I'm not sure which type of tool should be used for that sort of job... Could anyone point me to the right tool for removing the bottom bracket? Please see attached photo of my bottom bracket. Thanks in advance!

You don't need to remove or replace the bottom bracket to fit R7000 series 105 cranks (unless the bearings are won out of course). The Shimano SM BB72 bearings are Hollowtech II for a 24mm spindle so the R7000 will fit.

If you need to replace the bearings, special tools are needed to drive the press fit cups out of the bottom bracket shell and press new ones in. This must be done properly - the cups have to be driven out and pressed in square to the shell otherwise it can be damaged.

The tools are relatively expensive so it's a good idea to get a local bike repair shop to remove and press the bearings for you.


Remote rising seat posts and heavier rider I am looking at remote adjustable seat posts that I can adjust the height of using a lever on my handle bar. They have a high price tag.

Examples are
Rock Shox Reverb Seat Post
and
Crank Brothers Joplin 4 Remote Seatpost

Are these type of products ok with a heavier person?
Are there any other factors I should note before I buy one of these?
Other than the manual method of lowering, are there other options I should look at?

Both seatposts you mention use an air spring, with a hydraulic release. There is no maximum weight listed for either one.

They are designed to use your body weight to drop the saddle when the remote lever is pressed, and to use an air spring to return it to full height the next time it is pressed. You need to be off the seat when the lever is pressed to return the seat to its normal position, regardless of your body weight.

In addition, I'm a big dude, and I have no issues with mine that are weight based. I wouldn't be worried about it.

The Rock Shox Reverb is a solid unit, and the crank brothers design looks to be as well, although I've only ridden the Reverb. The one issue I've seen is that the remote levers are exposed, and sensitive to impact. I've damaged mine by resting the bike on the handlebar to cha nge a flat, even done carefully.

Bright side is, parts are cheap and easy to find, and the bleed process is easy.

I do recommend the Reverb.


What model/year is this bike? bike http://images.craigslist.org/01010_iSEhT1sECUO_600x450.jpg

What model/year is this bike?

I was wondering because the owner of the bike does not know!

Thank you :D

(I've never owned a cannondale bike) judging from the parts :

a triple crankset
bar end shifters
cantilever brakes
the rims seem wider than typical road bike rims.
a long cage dérailleur to accommodate big cassette (Not sure since the pic isn't the drive side)

It's likely a touring bike, so it's probably a modified Cannondale SR300, or Touring 1


wheel size confusion My bike is a Genesis Day One 2011 originally Alfine 8 hub, only thing is I bought it as a fixie without the hub. I wish to purchase an Alfine 8 hub and wheel and revert it back to it's Alfine 8 glory. Current wheels are 29".
I was thinking of only purchasing the rear wheel complete with hub...it is all I need. Tho, I am encouraged to buy a pair of wheels rather than just one rear as it is easier to sell a pair than just one rear wheel (the ones I would take off).
The only thing is, that wheels available within my budget are both advertised as described below.

My Q -
On the website the rear wheel with the Alfine 8 hub is described as 28" with dimensions of 622x19.
And the front wheel is described as 29" with dimensions 622x19.

What is the difference? Dimensions are the same! Could I use these two wheels together with the same tyres I already have?

Some say 29"and 28" are the same just marketed differently for different bikes, others say they are different...what it is then?

Any help and clarification welcome!!!!!!!!!

Inch measurements for wheels are really just labels that often refer to the diameter of the rim plus a nominally sized tire rather than an accurate measurement of the rim diameter.

The 622x19 spec is what you need to pay attention to. 622 is the diameter of the rim bead seat in mm. 19 is the inner width of the rim in mm.

Look at your tires, if they are marked 'ISO 622' or 'ETRTO 622' or '700C' (an French system label that is the same as ETRTO/ISO 622), then they are 622mm diameter.

You can measure the inner rim width of your rims. They don't have to be exactly 19 mm for your current tires to fit. A tire of a given overall width will fit on a range of rim widths.


66 yo female road bike rider needs advice on THE BEST CLIMBING components/groupsets available! I'm a  66 year old  female rider with a heart condition on a Waterford road bike, currently using Shimano Ultegra 6703 Triple 10 sp chainset-170mm 52-39-30T and find that since I've moved to the Smokies, it isn't enough. I love riding and don't mind changing out ALL of my components if necessary in order to climb without stressing my heart. Would it make sense to swap it all out for mountain bike gearing? Move to SRAM components? Other???I LOVE cycling...but want THE lightest and easiest climbing components available. Please help!!!

Also consider some help from an ebike motor.  It may not be fully to your preference, but the small push on the steepest bits will help save your knees and your heart.

This may go against the "purity" ethos that some cyclists value, but at the end of the day its all about riding.

There are retrofit wheel kits for existing bikes, or a bolt-on mid drive, or a much more subtle bottom bracket booster like that woman used in the CX competition (apparently by mistake)

A higher end solution would be to get an electric road bike where the motor is integrated into the frame at the bottom bracket, and batteries are stored in the downtube rather than bolted onto your water bottle mounts or out the back on a parcel rack.  But that's much more cost.


How to get enough leverage to remove pedals when their cranks are not attached to a bike? I'm trying to troubleshoot a weird barely-felt click on my cruiser. The nest step of the process is to swap out the pedals and see if the problem goes away (if not, the problem is likely the bottom bracket).

I've replaced pedals before, own a good pedal wrench, and know how to remember which pedal has reverse threading. I was surprised to find that I couldn't get my only spare pair off the cranks--they were removed from a bent frame for me by a shop, an currently live in a box next to the frame I'll eventually hang them on. I usually grip the crank opposite to the one I'm removing a pedal from, but I can't get any leverage with just one crank!

TL;DR/ The question: How do I get enough leverage to remove the pedals from these free-range and short mountain cranks?

The best option would be to place the crank in a table vise - or in a pipe that has been gripped in a table vise.

If you don't have access to a vise, another option is to try and attach the pedal wrench so that the handle is only a few degrees away from inline with (right on top of) the crank, so that you squeeze the wrench and the crank together.


Front Derailleur 10T Capacity (XT FD-M8025) I'd like to move from a 1x11 crankset to a 2x11 crankset to extend both my high and low gear range.
Shimano has indicated that their XT M8025 Front Derailler has a 10T capacity.  It means that I could only use a 10T set-up between my front chainrings, such as running a 36-26 combination (10T difference).
My goal is to run a 36-24 combination (12T difference) with an XT 11-42 Cassette. Is it possible to run such a combination with an XT M8025 FD "without noticeable" impediments ?
Your answer or experience is appreciated. Bike tinkerers please chime in.  Thanks :)

I don't know the severity because I rarely encounter recent mountain FDs and hacky setups for them even less, but what will happen is the contact it makes with the chain when shifting off of the small ring will be suboptimal. That kind of problem will vary with what cog the chain is on in back, i.e. better in the lower gears. There can also be problems with the chain wanting to drag on the cage in some small/small combinations.
You'll probably get a better performing setup by running a wider cassette and cheating the RD total capacity. Shifting will be largely unaffected and you'll only be down the ability to use some small/small combos, which will be compromised anyway if you do what you propose.


Eagle chain B-gap adjustment without plastic tool SRAM makes this plastic tool for adjusting the B-gap on their Eagle derailleurs. My question is, if I want to measure this distance without this tool (say with a caliper instead), how should I go about it? Between which two points should I make the measurement and what's the value I should aim for?

This measurement is given by both Shimano and SRAM as the shortest distance between the circles formed by the tips of the teeth of the largest cog and those of the guide pulley.

The spec for Eagle is 15mm.

A simple way of actually doing it is to hold up a 15mm wrench, caliper, track nut, etc to it.

Give it a little fine tuning once the chain is on and you're setting up the shifting. You'll be able to tell how small changes (1/4 turn-ish) have some bearing on how smoothly and quietly it all works.


Are bike chains in Europe different? I tried to change the crank set on a bike brought over to the USA from Europe, assuming all bike chains were the same. The original chainring had 40 teeth and I wanted to try one with 44 teeth. The new chainring had a larger diameter as I expected, but I thought the separation of the teeth at the circumference would be the same. Well, I was wrong. The chain links simply didn't fit the spacing of the teeth on the chainring - after a half dozen teeth the chain was not sitting on teeth at all. Is there a difference between chains in the US and Europe?

There have been exceptions, like Dura Ace 10mm Track, but for the most part 1/2" chain pitch is totally universal. Pairing a heavily worn chain or chainring/cog with a new part can result in what you're seeing, though, because of the mismatch in pitch that develops as chains wear.


Is cycling in my DNA? This is not meant to come across ignorantly or demeaning to other people I've cycled past.
When I come across other cyclists in long or short rides, I feel like I'm holding back to save hurting their feelings. It doesn't matter if they are commuters or group riders with rapha jerseys and bikes I can't afford. I have a used Bianchi that I got for £500 from a colleague at work. So it's nothing to write home about and is a very basic gear setup. It's a hybrid bike.
For example, there was a solo rider on my way to work and he looked to be putting in an effort on a climb. I didn’t get too much of a look at the bike, but it looked like a giant TCR. And he wore the normal cycling bib and jersey. I was wearing baggy joggers and somewhat loose jacket. I don’t know how long he's been riding nor the amount of time he has been riding for this specific ride. I got past him in no time and never saw him again after that.
Before I got my bike I walked everywhere. At the gym I could easily lift a massive weight with my legs. My legs have always been "big" and it wasn't due to my weight.
Sorry, I'm kind of stressing myself out about this. Do I have above average cycling legs unintentionally or did I just happen to condition my legs to be this way? Is it genetically a thing? None of my family have ever cycled, but yet I can go past everyone I meet in the streets that are cycling.
Before anyone says anything, I am not putting effort in to go past anyone; I'm going at my normal pace.

If you really want to find out, look for a local time trial route and see what people can do on that.
There's also an advantage coming up behind someone - not so much the aero advantage as you have to get close for that, but the knowledge that there's someone to catch up with - your head goes into race mode, even just a little, but theirs doesn't.
Some riders have all the gear but no fitness. Others are having off days. I've seen the effects you note from both sides. Within the last few days I've blasted past 2 roadies uphill while on my shopping bike with a big backpack, and struggled to make much headway at all on my faster but still heavy bike after wearing myself out earlier in the ride (140km with some rough gravel). Flat out on the TT course near me I might average 21mph for half an hour, commuting on the same bike little more than half that unless I'm rushing to get somewhere. But my fast pace would be almost last looking at events on that course; winners are 50% faster than me.


Training for long distance rides (> 200km) I want to be able to ride about 200-300km in about 1-2 months, but right now there's no weather where I live for cycling, so until probably April I have to train in a gym.

I'm 170cm and 72kg, since 3 weeks, I:

have a diet, eat max 2200kcal a day
do gym trainings 3x a week (12-10-8 reps for all body parts per session)
do spinning classes 2x a week (1,5h now, and increasing)

Is this enough? Should I change something?

While gym and spinning are good complementary activities to cycling, I would recommend that you also look at adding an element of riding on a real bike (like the dark knight said in his comment).

For long distance road riding, there are a number of things you need to practice.  In my honest opinion, the two things that need the most practise are:

Sitting down in your saddle for a long period of time - 200 to 300 km will see you sitting down anywhere between 8 and 18 hours (depending on ability and terrain). That is a VERY long time in the saddle even for an experienced rider with the best type of shorts / saddle.
Nutrition - One does not simply ride for more than 3 hours without a tried and tested nutrition plan!  Your body usually stores around 90 minutes worth of glycogen (at Tempo effort). This means that around that time, you should have already eaten and digested food, ready to be burnt up by your muscles.  You should top up these reserves as often as possible, so that you do not go into a minus and become hypoglycemic (bonking).  I usually eat a bar every hour on the hour, sip carbohydrate drinks every 15 minutes (700ml an hour) and I top up in between with gels.  A typical 4 hour bike ride for me burns 3500 calories.  Pro-riders easily go through 8000 cals a DAY!

In addition to the above, it's very important that you have a bike that fits you properly.  I'd recommend having it professionally fitted because you feel all sorts of pains after sitting in the same position all day!

If the weather is really as bad as what you say, then you could consider getting yourself a turbo-trainer or rollers.  You'll get used to sitting on the bike you'll be riding, and provided you have the time, you could also practise your nutrition and eating and drinking on the bike (if required).


How can a GPS with damaged screen be put to use? I bought a Holux 260 Pro last year but it fell off the bike on very first day, due to faulty clamp. Sending it to the company for replacement is very costly(>50% of the device cost) so it's been lying around for over a year.
Except for the broken screen, the device is fully functional. I can't use it normally as the screen is totally damaged. Anybody having some good ideas to put it to a good use?

I'd figure out the key combinations to start and stop recording, and enable .gpx track recording.

You could then plug it into a computer and extract the .gpx files, and then use tools to play with them:

http://www.gpsvisualizer.com/ will let you upload the file and view it on a map
http://gpxdataanalyzer.com/ is a site I wrote that will analyze the file and return some analysis on it if you pick an activity (Flying, Driving, Hiking, etc.) I should probably add bicycling.
Any number of tools (including the Garmin software that comes with their GPS units) that will allow you to visualize the data 'off device'.


B01S brake pads for Deore A-M615 brakes? I bought replacement pads for my Deore A-M615 brakes. They installed just fine. But after cleaning the old pads, I saw that they are G01S, while the new ones are B01S.

G01S, the original:

B01S, which I bought by mistake:

The "incorrect" B01S have just fitted fine, and seem to do their work equally good. Should I now:

ride as usual?
buy the correct pads, ride carefully before that?
buy the correct pads, not ride with the wrong ones even to the LBS?

The G01S pads are slightly wider, and slightly shorter, than the B01S which you replaced them with.  If you compare backing plates carefully you will see the difference.  I know this because I thought they were all the same but a genuine Shimano bleed block wouldn't fit in a BR-M395 caliper that has B01S as the specified pad.  You may need a digital caliper to measure the difference.

Thus you can stick the smaller B01S into a G01S hole, but not the other way around... A G01S will not fit in an Acera BR-M395 caliper (or a BR-M315, BR-M355, BR-M396, or Alivio BR-M445, or others that have th B01S as OE). I wouldn't use the B01S pad in your application because it'll be wiggly in your M615 brakes - The loads from braking are transferred to the beefy sides of your caliper, the through the caliper to the frame.  Wiggly pads will "wear out" your alloy caliper, making the hole bigger, and applying a torque to the split-pin that holds the pads into the caliper.

It probably isn't dangerous our anything, at least not over the life of one set of pads, but it will chew up your calipers some, which is more expensive than buying the right pads.


How to remove rust from gears? I have a 2 year old Diamondback bike with gears that have already rusted while living in the desert southwest.  I'm not sure how or if they can be cleaned.  Also, was something I should have done to keep them from rusting?  Any advice would be helpful!  Thanks

By "gears" I assume you're talking about the rear sprockets, or perhaps the smallest front sprocket, since they're about the only "gears" that are made of steel.  And they shouldn't get rusty if properly oiled.

A little rust won't hurt the sprockets.  Just oil the chain with good chain oil and it will transfer to the sprockets fairly readily -- the rust will wear off with a little use.  More worrisome is the chain itself, since a little rust can hurt a chain, causing "frozen links" and accelerating wear.  Again, oil it with proper bike chain oil.


Chainrings for Shimano FC-M760 crank worn out, need help Problem: I have Shimano XT FC-M760 cranks 22/32/44t on my MTB. BCD=104/64, 4 bolt. Need to replace all rings; I'm open to any solution other than changing to 2x/1x (2x10 not enough gear range, 1x11 too expensive).
Everywhere I look the big ring is discontinued or out of stock. Small/middle are hard to find but I eventually found a source.Tried to find replacement triple crank, very few options available, no XT. Tried ebay, prices are high and parts are worn. I tried to buy compatible Shimano rings (hone/saint), no luck.
specific questions:

Any links that show what rings (brand/model) fit those cranks? I know there may be a problem with the "tab length".
Any sources that sell the big ring (42 or 44t)?

Update:
Bought Truvativ Trushift rings. Middle ring did not fit, big ring fit but I had to file down the pin (see longer comment below).

It's a very populous crank and generally speaking any aftermarket/replacement type chainrings will go on it. It tends to be true that the designated Shimano chainrings make the best replacements for their cranks in terms of performance, or at least avoid minor weirdness with spacing or spider fit, but it's rare for those issues to be insurmountable when fitting aftermarket replacement rings on to a mainstream crank like this.
There are some 104 rings where the rounded contour of the spider can be a mismatch. If memory serves you get into this from mounting Truvativ/SRAM rings on Shimano cranks, but I may have that in reverse. You knock the ring down slightly with a half round file and it's fine.
Some brands to look out for aftermarket replacements are Origin8, Dimension, Blackspire, Vuelta, and TA. The 2020 parts shortages have not hit generic replacement chainrings that hard and I see some of these are still readily available from distributors.


What is the lifespan of a typical road tire? Assuming no accidents, cuts, or other major traumas, what is the useful life of a typical decent-quality (maybe a Schwalbe Marathon as reference?) road or commuting tire, measured in distance traveled and/or time since installation?

Put another way, when should my backbrain be niggling at me to get new tires?

Related but not identical: What's the shelf life of tublar tires?

Here is Sheldon's take on it: Your backbrain should be niggling you when you start to get some punctures or the fabric layer/belt (which gives the structure of the tire) of the tire is about to show or is damaged. Unlike a radial, where the tire is integral to keeping the wheel working, all a tire has to do is protect a tube. The rest of the stuff is aesthetic. Proper inflation is important for controlling wear though.

Schwalbe's marketing material says that Schwalbe Marathons should last between 6000 km and 12000km, but I'd be inclined to say thats conservative in good riding conditions - I have much lower quality tires than Schwalbe Marathons which are closer to the higher end of that range and show no signs of giving up (this is for commuting, and they have around 7000 miles on them, but this is on a 26" rigid mountain bike so significantly bigger tires than you're likely considering, so maybe not a fair comparison).


Need I mount my wheel flush to the top of my fork ends? Using 28c tires with a recently purchased carbon fork, I found I had only ~1mm of tire clearance from the top of the brake caliper. However, if I mount my wheel slightly lower in my fork ends so that it just clears the lawyer tabs, but is no longer flush with the top of the fork end, I have a more acceptable ~3mm of tire clearance.

Is there any danger in riding my bike with my wheel mounted in this way? I am using QR skewers if that matters.

The QR interface is designed such that the axle is fully seated in the dropouts before engaging the QR.  The QR engagement should be firm, but it is not designed to hold the wheel in the way you describe.  Dangers of trying to do what you suggest are:

Severely over-tightening the QR (which you may need to do to keep the wheel in place) could potentially result in QR breakage. If the QR breaks there will be nothing to hold your front wheel on and there is a very good chance you will end up in a bad crash.
If you do not seat the wheel, it is easy to accidentally clamp on an angle.  Given you want to clamp a fair ways down in the dropout it is easy to get really off-angled if you are not paying attentions.  As in (1) if you are severely over-tightening this could damage the drop outs and contribute to problem (1).
Even if you can get this to work, 3mm of clearance is still incredibly tight.  Tires can expand and contract with temperature and speed (meaning this clearance could start to disappear) and small debris picked up by the tires could result in a jammed wheel (briefly giving you the ability to fly).

If something does go wrong my bets are on (1) or (3).  The short of it, is that your frame simply isn't designed for 28mm tires.  This is the issue with short reach caliper brakes (now what most define as standard reach).  Frames with mid-reach caliper brakes can support tire sizes up to around 32-35mm depending if you want to run fenders as well.

Unfortunately, the N+1 rule has struck again...


Why some IGH have off-center flanges? I was browsing specifications of internal gear hubs and noticed that many of them have flange center moved to left (relative to hub center). I'm wondering why, I think IGH should have symmetrical flange distances for same spoke tension on both sides.
Some examples:
https://www.kstoerz.com/freespoke/hub/169
https://www.kstoerz.com/freespoke/hub/168
https://www.kstoerz.com/freespoke/hub/167

It's a good observation.
Symmetrical flange spacing and the maximized total spoke tension it provides is exactly what one wants in some applications, but not all. If you're designing a hub you have to think about what is enough total tension and then parlay the benefits of getting "extra" strength above that amount versus the drawbacks of reducing the bracing angle, albeit only in one direction. When wheels fail in practice, a pretty meaningful percent of them fail from side loads. So when you see this asymmetry on hubs that could have been made symmetrical, it's the designer making decisions on what will actually produce better reliability on average.
An exaggerated version of the same thing is seen on track hubs. They're the most could-be-symmetrical hubs of all, but proper track racing hubs usually aren't. The reason is that radial overloading is just not that much of a concern, but crashes and heavy sprinting riders rocking the bike side to side are.


Tubeless valve leaking, what exactly is wrong & what do I need to do to fix it? My front tyre has started to leak air at the top of the presta valve.

It's very noticeable when the valve is unscrewed or even not really tightly screwed in: you can feel a breeze coming out of the top.

When I screw the valve cap around past max tightness it slips & lets out a hissing noise.

Even with the valve tight enough that you can't feel or hear anything, the tyre runs dead flat after about 2hrs.

I'm pretty new to tubeless, and I've never had a valve act like this before.

The tyre is a Gavia AC 2. What do I need to do to fix it?

edit: looks like I might be loosing sealant, and need a truing - the rotor is rubbing the calipers at one point :(

When I screw the valve cap around past max tightness it slips & lets out a hissing noise.

The most likely thing happening here is that your valve has a removable core, and you have slackened it off.  You can get special tools for the job, but usually the valve core has a small flat area that you can grip carefully with some pliers to tighten it again.


Identifying features of a mountain bike specific to a tall and heavy rider? I recently found some local bike trails that have everything from flat gravel to dirt bike jumps. I'm looking for a bike that can hold me through off road biking. I don't plan on doing any jumps or anything, but definitely offroad trails.

I've looked around a bunch and haven't been able to find many bikes that have an actual weight limit listed.

I'm hoping to find something around the middle of the price range, but I know most things for heavy guys tend to be a lot more expensive.

I am brand new to biking so any and all tips are very much appreciated!  I'm 6'3" (~190cm) and 325lbs (~147kg).

I would be looking at bikes with frames made of steel. A cro-moly frame will be most likely to meet the requirements you are looking for on your budget, and there are a lot of bikes with cro-moly frames available in different price ranges. Companies like Trek and Diamond Back make high quality bikes in every price range, you would just have to look at how each bike specs out for weight limits. Dont rule out alloy bikes, I just think they tend to fatigue faster under rigorous use. There is a company called Zize Bikes that might interest you, although they look pricey.


Fixed gear steel frame from AliExpress I would like to build my own fixed gear bike.
I want a steel frame, I know different quality of steel and I want to avoid HI-Ten.
I will be mostly for urban cycling (pavements) and I would take rougher paths from time to time. So I need wheels with at least 28mm large (so not a tight fork).
I live in Switzerland and looking on the Internet, I didn't find my frame.
I never bought on AliExpress, I am afraid I will have bad surprise (counterfeit) while I was looking for this frame :
French: https://fr.aliexpress.com/item/1005001398900346.html
English: https://www.aliexpress.com/item/1005001398900346.html
German: https://de.aliexpress.com/item/1005001398900346.html
I mean what is strange is that they say the type of the frame is : Steel Cr-Mo 4130/525/725/Tube Reynolds Columbus.
What does it means to put at least 3 kind of steels and one of the best two manufacturers of frame in the world (Reynolds and Comlombus) ? (they made a mistake writing Columbus ... but I don't know if it's because of poor translation)   Is it serious ?

No, it is not serious, you should not believe these descriptions. They just try to attract people searching various terms.
There are indeed many counterfeits in these shops. When they claim so much different stuff at once it is quite certain.
That does not mean that the frame would not work, but if shopping in Asia it is better to shop from brands that do not pretend they are something else and sell under their own Asian brands.


Can you use a 6/7 Speed Derailleur on a 5 speed bicycle? I bent my derailleur beyond repair today. I'm an inexperienced cyclist.

I have a 5 speed Takara. Can I/Should I replace it with a 6/7 speed rear derailleur? I am having trouble finding a 5 speed one and the local bike shops are suggesting I just get a 6/7.

In addition, how difficult is it to install the derailleur?

Thanks.

If I'm not mistaken, you're talking about non-indexed derailers, plus the chain width would be the same for 5 and 6/7, so there should be no problem.

Installing a derailer is a fairly simple task, in and of itself.  But you either have to break the chain or disassemble the derailer to get the chain threaded through it, and that's a little more involved.  Plus you need to adjust the derailer once installed (though adjusting a non-indexed derailer is almost trivial).

None of this is beyond the abilities of someone with some mechanical ability and a modicum of patience, but it requires thought, care, and a few tools.  And note that you'll maybe want to replace the shift cable at the same time, as the existing is likely too frayed to reuse.


Will a "700 x 25-32cc" inner tube fit my "700Cx28/38c" / "ETRTO 622x20" rim? I have a road bike that has a flat tire, the rim is marked with the text

  700Cx28/38c  ETRTO 622x20

I am specifically looking at this Continental tube on Amazon. Under the sizing options there is an option

  700 x 25-32cc

Which I think is the one that I want. The picture of the box (not necessarily correlated to my choice in sizing) has the text

  20-622 > 25-630

Which again seems to confirm that this inner tube will be correct.

Will the tube size mentioned above fit the rim I describe? Or, should I select the size 32-42cc because the range on the rim (28/38c) has more #'s in the range 32-42 (6) than it does in the range 25-32 (5)?

I have been reading for a bit now and from what I understand the text on the rim (28/38cc) means that the tire (not tube) size that the rim will fit is between 28mm and 38mm. But what is confusing me here is the sizing of the tubes listed as that are listed as, for instance, 25-32cc. Does this mean the tube itself will fit on rims that can fit tires (not tubes) in the range of 25mm to 32mm?

In the end what exactly should I be looking for; what sizes of tubes will fit this rim properly?

I hate to "beg" for the answer seeing how much it is looked down upon on the stackexchange sites but I seem to actually be at a loss in understanding this correctly...

EDIT: Ok so I think I understand this much better now. My tire itself has the text 700x40c. Which means that the tire itself "prefers" a tube with a cross section of 40mm; moreover the tires cross sectional area is 40 mm!? So I can then buy any tube that says it will fit/(inflate to) a tire with a cross sectional area of 40c.

It looks as though you're confused about the range of allowed tyres on the rim vs the tube. What connects the two is the size of the tyre you actually have.

There are two independent ranges. The rim is rated to take tyres in the range 28 to 38mm wide. Your tyre will be an exact size, and ideally should be within that range. You can measure the width or guess, because it's not critical.

That's because the tube will be rated to fit a range of tyre sizes. The one you're looking at will fit any time from 25mm to 32mm wide.

As long as the tyre you actually have is more or less the size of the tube, you'll be fine.

In practice a thinner tyre will be fine, it might just be hard to stuff all the tube into the tyre when fitting it (it's more obvious if you're trying to fit a 55mm wide tube into a 22mm wide tyre... and that example might not actually work because there will be so much rubber filling the tyre that you might not be able to get any air in).

The same applies to tyres, BTW. You could probably run 25mm or even 23mm tyres on that rim without problems, and likely 40mm or 45mm wide as well, if the tyre cleared your frame. I dont suggest you actually do run wildly out of spec tyres, but people do (I have run 55mm tyres on narrow rimes before).

Also, tyres fit a range of rim widths :) One guy I met ran narrow tyres on wide rims because he was convinced it lowered the rolling resistance. He may have been right, but it made hard cornering quite exciting when the rims hit the ground.

I suspect you're over-thinking this. It's straightforward once you understand it. (rim takes a range of tyres) + (tyre is one exact size size) + (tube fits a range of tyres).


What caused this seat clamp / frame failure? Here's my "long distance" ride, which is an old steel MTB without suspension.

I picked it up by the saddle to move it and felt some play, I thought the saddle rails might have been loose, but as per picture, there's a crack 90% of the way around the frame.

I have bent it open a bit more with medium finger pressure.

The crack shows evidence of rust, so its been a slow break rather than a sudden one.

I'm 100 kilos and have long legs, with a standover height of 91 cm.  The frame is too small for me at 20" / 51 cm.

The seat post was reinforced internally with extra pipe (I have bent seat posts before).
The post extended 10cm into the frame (i.e., well past the crack) and then 29cm up to the seat.

Strava says I've done 2,949 km on this bike in the last 15 months.

So my main question: is this an old-age fatigue failure of the frame, or did I break it by being too tall, or too heavy?

Second – is the frame repairable or is it now scrap?

It looks like plain old metal fatigue. Most probably there was a hairline crack, then water got into it and rusted it out.

Note that when you extend the seat height, you increase the lever arm of the seat post and put a considerable amount of stress on the frame precisely at that location. It doesn't help that the design of that seat clamp has no reinforcing material and is high-up, further increasing the leverage on it. Poor design.

The good news is that it's a steel frame. You could take it to an auto body welder and they could easily fix it for less than an hour of labor. Since they can't weld from both sides (the seat tube wouldn't go in), it'd still be weak and susceptible to damage. Or you could try rebrazing it yourself.


How to get a decent workout on a mid sized, flat parking lot? I'm looking for a way to have a bicycle based workout in the middle of the COVID-19 quarantine.

I do not own a roller trainer of any type, nor materials good enough to make one myself. In my country there is a full(ish) lockdown and I cannot go out for training.

I live on a building complex that has a mid-sized parking lot but it is almost completely flat.

I'm searching for a way to increase resistance to the bike to get a meaningfull training out of a 40-60 ride.

The first idea thar I have is to put a rubber band to depreess the rear brake lever to make it act as a drag brake. (disk brake) (Would it damage or excesively wear the brakes pad/rotor?)

Another idea is to put some sort of "fins" into the rear tire to make it generate air drag (Maybe attached to the spokes perpendicular to direction of travel).

The goal is to get a decent workout at a moderate speed, the parking lot is not big enough to accelerate a lot, and does not provide a loop path, (I'd be like making a 'C' shape going back and forth.) Also, as it is a parking lot, I do not want to go full speed to avoid hitting or scaring a neighbor who may be walking to/from their car ans suddenly pops up in front of me.

The fins idea could also be adapted to a simple stand that lifts up the rear tire to make it trainer like.

Any additional ideas on how to get a workout are appreciated. I'd also appreciate anecdotal information if you wave opted for such an approach sometime.

I'm DIY oriented and Currently I have with me a bike with street tires, and a bike with mtb tires. A spare worn out wheelset and some tools, and I cannot go out shoping for parts, materials nor extra tools.

EDIT: Here I cannot buy online parts nor other goods than food or medicine. There is simply no such comerce stablished in this country. Any online buying I've done involves shipping to a P.O. Box and paying a second carrier to bring it from USA to my country. Currently such service is not active as only health/food/journalism workers are authorized to move on the street.

I did read some applicable ideas on this answer: https://bicycles.stackexchange.com/a/61837/2177

Consider constructing a parachute similar to those worn by sprinters: https://www.amazon.com/SKLZ-Speed-Chute-Resistance-Acceleration/dp/B002CLK21C

This would generate significant drag at moderate speeds.  Just be sure not to get it tangled up in the rear wheel!  Perhaps install an emergency release to avoid getting tangled yourself.  It's been discussed here: https://www.bikeforums.net/33-road-bike-racing/273066-anyone-ever-use-sprinter-s-parachute-added-resistance.html

Another option is to wear bulky clothes that would act as a parachute/sail.  I often achieve this effect unintentionally with rain gear.  Throw your bike into high gear and grind away!


Rickshaw electric conversion Is it possible to buy a traditional pedal rickshaw and stick an electric bike conversion kit on it? The rickshaw I've seen is the type when the rider is at the rear and so has two wheels at the front and one at the rear.

Tadpole-style trikes with one wheel in back are quite easy to electrify.

You can either use a rear hub motor or a bottom bracket motor. Given the high startup torque requirements with rickshaws and thus the desirability of low gearing and a range of gears, I’d recommend a bottom bracket motor such as a Bafang BB - the only concern is if there’s enough clearance to mount the bottom bracket motor around that frame. This allows you to have a pretty good range of gears using a rear derailleur or internal geared hub such as a Rohloff on back.

You can reprogram a BB motor controller so that max assist is limited to 250 watts or max assist speed is limited to 30 kph or whatever your local laws are. Proving that your assist is limited in such a fashion to a constable that is trying to write you a ticket is another matter.

Hub motors that have two or more gears are available but their long term reliability is still unknown — and even with gears, hub motors unfortunately don’t have great starting torque.


Do both SH51 and SH56 cleats work with all SPD-compatible pedals? This answer mentions that Shimano makes two kinds of SPD cleats, one that allows unidirectional release (SH51) and one multidirectional (SH56).

Are there other differences between the two? Will both types work with all SPD-compatible pedals? Are there reasons to prefer unidirectional release over multidirectional release?

Yes, all SPD pedals are compatible with both of these cleats. The multi-directional release SH-56 will allow you to pull out of the pedal vertically if it is required. They are designed for spin bikes. (Exercise use.)

The difference is a preference only, because it depends what you intend to use them for. I will not use the SH-56 on the road because I have pulled out of the pedal during normal riding, and offroad has similar issues.


Identify 1980's Bianchi? Can someone please help me identify this bicycle?

My mom has had it in storage for ages – I believe it's from the 80's or early 90's. I'm not sure what is original and what was changed... But you all probably know far better than I, so here are some photos!

Thanks in advance :))

xx

The bike might be the a 1981 Rekord "W" Strada, at least this catalog page shows a very similar photo, but no exact parts list:

It might also be another Bianchi mixte-style frame with components swapped, i.e. flat bar to drop bar, which makes identification harder.

Or it might be a late '80s (possibly 1986) womens Bianchi Strada, as shown in this question. Note that serial numbers on both bikes are very close: 51027534 vs 51027563.


White Industries ENO on a Hope hub There seem to be two approaches to single speed freewheels:

Screw on to the hub a combined freewheel/sprocket combination (eg. White Industries ENO)
Slide on a single sprocket to an existing splined freehub body, and use spacers to correct the chainline

I have the former (KT-SY1F / KT-MX7R 6-Bolt Disc hub, Shimano SF MX-30 16T), but I am thinking about upgrading my wheels.
But most high-end hubs (eg Hope Pro 4) appear to come with a splined freehub body. Are these compatible (or can they be made to be compatible) with the screw-on freewheel/sprocket combo? If so, can the chainline be corrected for in this configuration?

No, there's no way of getting a singlespeed freewheel onto a cassette hub or a singlespeed cassette cog got onto a freewheel hub. ENO freewheels mostly exist to provide a high-end, high engagement rate option for hubs and trials cranks that need a singlespeed freewheel.


Can the iBert safe-T-seat be safely mounted behind the seat post? I have the iBert front-mounting child seat. I've used it previously attached to my street bike as in the below image, but between the straight bars and the shifter triggers, I had to mount it so low that my knees knocked against it while riding, which is a non-starter.

I recently acquired a long-tail cargo bike with cruiser-style handlebars, which I intended to use with the iBert seat. Unfortunately, the stem is fixed-height and does not have the 3/4" straight length between the frame and handlebars required for the T-bar mounting post (see the maker's website).

However, the seat post is adjustable, so I thought I might be able to simply mount this seat in the rear instead. Most child seats are rear-mounted, the seat post seems as durable as the stem, and in this configuration the seat won't be moving side-to-side as it does when attached to the stem.

I can't find anywhere on the maker's website that this is explicitly prohibited or warned against. I have emailed them, but the response I received was that they have been purchased by another company and "appreciate your patience" while they go through that process - no response with respect to the mounting locations. I also don't see anything online that addresses whether it's a reasonable "hack" to mount the seat this way. The mounting bar is a simple assembly with two bolts that I'm sure I'll be able to physically attach to the seat post, high enough to clear the rear rack. What I'm not sure of is:

Is this likely to damage the bicycle?
Is there reason to think this would be unsafe for my passenger?

I am also not sure if the legs of the seat will interfere with the rider in front; assuming it's safe enough for the passenger and the bike, I can test that out on my own.

The bike is equipped with a sturdy double-leg kickstand, such that both tires are in contact with level ground when the kickstand is deployed and the bike is stable for loading/unloading.

Wth the childs's legs sticking forward the way the website suggests, you've got no hope.  You could easily check this by fitting the seat and trying to ride without the child -- that way you don't even need to do the clamps up tight.  You're also likely to find that the slumped-foward head rest sticks into your lower back and means that you're badly positioned on the saddle -- just what you don't want when you're controlling a bike with an extra load up high.

It's got more support than most front-mount seats but in general they're designed for you to have your arms round the child and your back behind them.  This one still has a very low back, and if the child falls asleep behind you they'll be flopping around like crazy and you won't know about it (though this happens even on much bigger rear seats as well, at least then their head can't flop backwards going over a bump.)

Most people I see riding with front mount seats have to ride with their knees very wide to avoid the seat -- and this is a wider seat than I've seen on the road.  It seems to me that there's only quite a limited set of bike/rider/conditions combinations for which front seats work: You need to be at the small end of your frame's adjustments, with wide bars, and riding on flat roads where you don't need to work hard to accelerate.


Proper crank arm spacing? Is there a proper way to space crank arms in relation to the bottom bracket? Ive noticed most builds are generally +10mm on the right side in relation to the bottom bracket, but i feel like maybe they should be even for leg ergonomics? Is there a standard here from edge of bb to the outer edge of where the crankarm mounts to the bottom bracket?

The gap you're talking about is more or less random and does not itself affect how symmetrical the Q-factor winds up being.

The quick visual check for Q symmetry is to eyeball against the chainstays, which is close enough in almost all cases to know whether there's a problem unless the frame either has an asymmetrical rear end or is smashed. To get an exact measurement, one uses the depth gauge part of a vernier against either the seat tube of a round-tubed bike or the back rim (after checking dish) for bikes with asymmetrical frames.


Trike with 60+ pounds basket possible? I noticed that many trikes have a basket in the back but I need something much stronger capable of carrying a golf cart battery which weighs about 60 pounds so is that possible to make a custom one capable of that weight or even better, capable of carrying 2 of those batteries simultaneously for 120 pounds total?  Could it just be made out of wood or is metal better?  Do you think having that much weight back there would cause any issues such as frequent flats on the rear tires unless I use super thick tubes?

I'd use a trailer for this.  There are ready-made ones like http://www.bobgear.com/bike-trailers or you could build your own.  Then a lot of the weight can go onto a dedicated trailer wheel (or two),  which should make it no big deal to carry two 60 pound batteries (assuming you have legs of steel, obviously).


Truvativ 1x front chainguide - what's wrong with this? I've been asked to inspect and fix someone's bike.  Its a heavy full-suspension Kona "Stab Deluxe" downhill monster from 2006.

The main fault is that the chain gets stuck between the front chainring and the chainguide.

It is a single 36 tooth chainring branded as Saint, with Hussefelt cranks and a 4 bolt Truvativ crank.  Not sure what the BB is other than external.  Seems to be stock/original components.

There's also a trailing lifter wheel vaguely like a jockey wheel but without teeth, so seems to be a tensioner but has no tension, perhaps best described as a keeper?

 Normal position

 Rotated forward by hand.

 Outline showing support system in the back.

My gut feeling is that the whole mounting bracket should not rotate like this.  From below I can see threads of the external cup (?) housing between the BB case and the chain keeper's support plate.

There is a lot of scoring and worn-off plastic inside the chain guide itself, suggests this has been loose or wrong for a long time.

Question What's wrong with this setup?  And how do I fix it?

Looks like the chainguard is of the type that mounts with a number of bolts that screw into the frame. You can see the slots in the mounting plate the screws go through to allow setting the chainguard angle. Presumably those bolts just need tightening?

I'd pull the crank and guard off and clean everything up as there may be dirt behind the guard plate. Looks like you will be doing this anyway if the BB is toast.

GMBN has a video on fitting this type of chainguard:


Chart for bicycle component quality? I'm not very familiar with all the different component groups available and wondered if there's a chart that ranks their quality (or price).

So I'd know that Shimano 105 is the same level as SRAM Apex (just and example, I don't know).  So I can get it in my head a general idea of where these component sets stack up against each other so when I look at bikes I'll know (generally) the quality of the components.

Surely there's a list somewhere out there, but I can't find it.

There are lots of comparisons in the web, however they tend to get outdated or vanish from time to time, so I won't recommend or link any particular one here. Instead use your favourite search engine with terms like "bicycle/road bike/mountain bike groupset comparison" or the like.

But you can also do a quick check yourself: Choose a component that is usually part of all groups (a derailleur for example), search your favourite online bike shop for it and note the price for the parts from different groups. This should scale fairly well to the whole component group and give you a rough estimate on how they are positioned towards each other.


Rear derailleur needs a couple pedalstrokes to change gear As of late I'm having some trouble with my rear derailleur.

When I shift specific gears (most likely to happen to the middle gears), the rear derailleur feels like it doesn't have enough power and needs another shift to change gears (when it does it changes two gears at once).

And when it does change 2 gears I have to shift one gear down again for my desired gear.

I have tried cleaning the whole thing as best as I could. There was a bit of gunk in the derailleur, so I carefully removed it and also cleaned the cassette extensively.

As always I'm going to consult with LBS anyway but maybe this is an easy fix I'm not aware of, because I'm too scared to touch any screws/parts myself.

Parts in question:

REAR DERAILLEUR SHIMANO RD-M390, SGS

I can't figure out what cassette it is though, but it mentions 11-32T on the parts list so I think that's the cassette "size" and it's 8-speed.

Only 500 km from new?  Sounds like cable stretch where the inner cable increases in length from new as it beds in.

Did you use up your free service?  Most new bikes from shops come with a 2-8 week "tweakup" to fix minor things like this.  If you bought the bike off the web, then its up you to fix it.

Firstly check out your brake line - there should be some form of barrel adjuster, often at the deraileur end.  Try undoing it a turn to tighten the cable (ie lengthen the outer), and see if it makes a difference to shifting.

Sometimes they're on the downtube (this is more of a road bike thing)

You shouldn't need to adjust anything else on your deraileur, so no screwdrivers or hex drivers needed.

This is easiest if your bike is hanging up off the ground so you can rotate the transmission.  Don't put your bike upside down, things don't work exactly the same the other way up.

Also its probably time to lube your chain.


Hydraulic brake not working well Recently I flipped my bike upside-down to get the wheel out as I don't have a workstand.  Now the brake is not biting until the brake lever is on the handlebar. Is there anyway to fix this?

Both the brakes are working but very slightly and they only work until I press all the way down.

If the bike is upside down and the brake levers are pushed then you can force air into the system resulting in the issue you are seeing.

There are a number of things you can try to restore function but if they don't work then a bleed will be necessary.

With the bike the right way up repeatedly pull the brake lever, this can encourage the air back out into the reservoir where it belongs.

If this doesn't work then zip tie the brake levers to the bars to pressurise the system, leave overnight and then try the first step again.

After that it's time for a proper bleed to get the air out of the system.  How you do this and what you need depends on the model of brake and may involve special sryinges and adapters at one extreme and a bit of tubing and a jam jar at the other.

If the brakes haven't been bleed for some time,  years not months, then a bleed might be a good idea anyway.


Tyre size and Turbo Trainers Are there any advantages in having a 700x25 tyre over a 700x23 when using a cycle trainer?

If you are "training", resistance is surely not a huge deal breaker. I assume cycle trainer tyres last a fair amount of time.

If it is just a way of transferring energy to a roller, I assume a bigger tyre will do that more efficiently.

The bigger tire will give you slightly higher gearing due to the higher diameter. You should get a trainer specific tire, as the compounds are harder to prevent overheating/excessive tire wear. Your tire isn't slipping against the roller on the trainer in either case, so the power transfer argument is relatively moot (theres rolling resistance and what not, but its not something you should be worrying about on a trainer...).

The reason why you'd get a 700x25 tire over a 700x23 tire would be that if your rim was wider, it may support a 700x25 tire better.  This is why some trainer tires are produced in 700x23 and 700x32 (e.g. Continental Hometrainer-- the larger size will fit some 29ers barely, which have wider rims). Most road racing bikes are designed for 23's so its easiest to ship 23's, which most trainer tires are, for road bikes. Also, there exist frames which will rub with a 25 but not a 23.

The TL;DR version: pick whichever one you want, provided your frame doesn't rub.

Also, I didn't find anyone actually producing a trainer tire for 700x25 -- there are training tires for 700x25 but they're for the road, not for the trainer.


Which winter road cycling shoes are rated for sub-15° F weather? Most of the road shoes I've found only seem to be rated to around 25° or so. Living in New England I'd like something colder. Does anyone know of road shoes rated for colder temps?

(They'll be used for commuting and weekend road rides)

Update: I have new Neoprene booties (Pearl Izumi Elite Barrier Shoe Cover) but find that they're only comfortable down to about 25°F or so.

The vast majority of cycling shoes (road and mountain) are well ventilated and not suitable for cold weather riding.  Lake makes an excellent winter boot (I have several pairs).  45NRTH makes the Wolvhammer, which I haven't tried, but have heard good things about.  There isn't a market for cold weather "road" shoes since generally road bikes become unsafe/unuseable after there is ice/snow on the road.

As far as getting the most out of the footwear you are using, I recommend NOT putting thick socks in your summer shoes.  Most people's summer riding shoes are close fitting, and adding extra thicker socks make keeping your feet warm harder since it compresses your blood vessels and restricts circulation.  If you can't stay warm with normal socks and booties / chem packs, you may need to look at purchasing a set of winter shoes with extra room for thicker socks.  My summer shoes are all 44s.  For winter, my shoes/boots are all 46s and 48s.  The 48s allow me room for two thick pairs of socks comfortably.

If you are going to using chemical heater packs, I suggest sticking them to the top toe of your shoe under the bootie.  The won't compress your toes that way and will get better air circulation / stay warmer.


What does vulcanizing solution in patch kits consist of? Can I buy it? I have a pile of old patch kits for inner tubes that are complete except for the little tube of "vulcanizing solution" that comes in patch kits. With time, these tubes crack, or have a cap fail to seal perfectly, and dry out completely. I would love to be able to buy a larger container of solution.

Vulcanizing solution appears and smells like rubber cement but I've seen suggestions that rubber cement simply contain similar solvents and/or polymers. None of my patch kits describe the chemicals in the vulcanizing solution tubes.

What is vuncalizing solution made of?

Can I obtain it in quantitites larger than a tiny tube in a patch kit? Could I make it? Can I at least obtain larger quantities of the little tubes?

The manufacturer sells said "vulcanizing solution" in quantities of 25g tubes through 1 gallon cans, so you should be able to buy it in larger quantities. Indeed, a quick search of Amazon yield 8 oz cans (or slightly cheaper), and while I couldn't find it on something well known like Amazon there are other places that sell the 1 gallon quantity. However, as many of the reviewers on Amazon point out, an 8 oz can should be a lifetime supply, and won't dry up nearly as quickly as those little tubes.

As far as what it is, that's a little harder to figure out. Checking the MSDS, we find only that it consists of 40-70% trichloroethelyne, an organic solvent. That doesn't really solve the problem, as that's just the solvent used.

To address the question of rubber cement, if we follow your link to Wikipedia, we find that it's generally a non-vulcanizing cement, while the tire patch stuff definitely claims to be vulcanizing.

Moving on, we can think about what the traditional solution to closely held trade secret formulas is. And the tool that was designed to solve that, though only does so imperfectly, is the patent system. Maybe we can find something in a patent filing.

A quick check over on Google Patents yields something promising, Cold self-vulcanizing rubber compositions; however, upon reading the patent, it's a three part mixture, and the process involves things like "the rubber used is a natural rubber, partially depolymerized by mechanical working and peptization with diorthobenzamidophenyl." I don't know about you, but peptization with diorthobenzamidophenyl is not exactly something I feel like trying to cook up with common household substances in my basement.

Reading further on, we find some further promising patents like Tire repair with cured patch or Tire repair by "patch only" method, but they all also involve discussions of the following form:

  Suitable vulcanization accelerators include, but are not limited to, thiazoles, sulphenamides, guanidines, thiourea derivatives, amine derivatives, and combinations thereof. Examples of these include, but are not limited to: N-cyclohexyl-2-benzothiazyl sulfenamide (CBS), dibenzylamine (DBA), N-N'-diphenylguanidine (DPG), Dicyclohexylamine (DCHA), 2-mercaptobenzothiozyl disulfide (MBTS).

As well as references to entire books on rubber and the process of vulcanization: 'Rubber Technology, edited by Maurice Morton, Chapter 2, "The Compounding and Vulcanization of Rubber," 3rd edition, 1987'

None of these appears to have any kind of description of a single readily available material or combination of a few that could be mixed together to work; they all appear to be fairly intricate, specialized compounds consisting of a variety of ingredients.

So I think that the 8oz can on Amazon is probably your best bet. I've heard some people claim you can just use regular rubber cement, but given that there are big cans of the "vulcanizing solution" readily available, my instinct would be to go for that.


Can I use a seat-post clamp/collar on the seat-post itself to prevent slipping? I have a Cannondale Synapse (2015 model), and have swapped the stock Cannondale seat-post for a Thomson Elite inline seat-post. However, I am experiencing problems with the seatpost slipping, even when tightening to 5Nm, as specified on the Cannondale frame. The seatpost clamping mechanism is an internal two-wedge system.

The frame is carbon, and the seatpost is aluminium. I am using carbon paste, but this does not seem to have truly solved the problem.

I am considering adding a Thomson seat post collar directly onto the seat post, but am nervous about adding extra downward stress onto the carbon frame.

You would be best served by first going to you dealer for advise. I am unsure why you would change the seatpost, as this may provide more salient information regarding your problem.

That said, if you really want to use the seatpost mentioned, it sounds undersized. You can buy seatpost specific shims. I again would recommend going to a LBS as they have the ability to best gauge the correct size shim, and order it for you. CF frames do not handle stresses that they weren't designed for well.


Can a tire that blew off a rim be safely used on another rim, and under what criteria? I have a set of tires where one of them blew off the rim on my bike after I slightly over-inflated it.

I originally asked a question about this here, and there are more details at that link. The tire did not appear to sustain major damage from the blow off, just some mild scuffing where the bead popped out over the rim. When I took both tires off after this, I did notice they're quite loose on my specific rims (easy to remove with hands, no levers required), so that's probably why it happened.

I was thinking of posting these online for free, with an explanation of what happened, and ask that whoever takes them just state clearly to me that the know the implications of a tire blow off, they know enough about bikes and tires to determine if the tires will be safe on their bike, and will take responsibility for any subsequent injury or bike damage if the same thing happens to their bike.

The tires seem to be in good shape and I think someone who knows bike can determine if it's safe to use them on their bike. I just don't want some noob throwing them on their bike and having the same thing happen while riding, leading to injury, etc.

So I have a several part question:

Can a tire that blew off one rim be safely used on another rim? If so, are there any special stipulations?

 2. Is it OK to give those tires to someone else, assuming I provide a detailed explanation of the blow off issue I had, and ask them to stipulate that they understand the dangers and know how to determine if the tires are a good fit for their particular rims? Or, should I just throw them in the garbage? Feel free to provide your personal opinion on this one, I don't think it has a concrete answer.

 3. Assuming I'm clear about the issues as outlined above, are there any legal implications (i.e. liability for me) if someone else has a blow off and injures themselves with tires I provided "as is"? I'm located in Canada.

Thanks.

I have a MTB where the tyres can simply be removed by hand once deflated.  The tyres are at 50~60 PSI normally.  But I can feel that they engage the clincher bead fine when inflated.

My guess is that your tyres never hook into the rim properly, and then overinflating found that area of the bead that wasn't fully seated.

As for the social side, as long as you clearly advise the recipient that you're giving them away, because they didn't stay seated properly on your rims then its the recipient's choice whether they use them or not.  I wouldn't want to see anyone hurt, but they'll be adults and can make their own choices.  Just help them to make an informed choice by sharing the history.


As recumbents are low to the ground and hard to see, how to you use one safely on a normal road? My wife thinks that she can't use a recumbent on the roads, as a car driver will not be able to see it.  What’s the solution?

Getting a high safety flag is common on recumbents (and trailers), at least in the US.

Photo credit


Is stem cap redundant after tightening stem bolts? Is it right to think that after the preload is set, and the stem bolts are tightened, the stem cap becomes redundant? Will the preload be held fixed by the stem? If so, does that mean the stem cap can be removed after preload is set?

Yes this is correct. Once the stem bolts are tight, they hold the system together. The top cap can be loosened without releasing the preload. You could try it out and you should find that the stem remains fixed and no play will develop.
You'll still need the top cap next time you want to preload the headset, so perhaps not redundant... maybe furloughed is a better word ;)


Trying to identify an old Helkama I have recovered I have an amazing find here and need help understanding it's history.  I am currently ordering all the bits and bobs to run it again, but wanted to learn more about it if I can.
I think it was a work bike, as shown with the sign on the back. Also has double pitted tires, a sign someone was maintaining it at some point. I think it is a Helkama, but it seems someone tried spraying "Nishiki" on the side.  What the heck.
It was found in Oulu Finland.

Helkama Oiva is more or less a civilian version of the bikes used by the Finnish army. They are known for being very heavy but quite fragile for their weight. The rear rack is very sturdy and perfect for carrying M85 backpack with shoulder straps wrapped around seat stay and support strut. The lock, chain guard and dynamo mount are additions for civilians.

The unique stem clamp where instead of usual expander cone or wedge, the steerer tube clamps around the stem, is a major security hazard. The steerer tube has normal threads and a cutout to allow deforming the tube. The threads provide a great starting point for cracks. The stem should be replaced with one with wedge immediately, or at least at the first time you notice that the handlebar feels loose. I had one of these bikes (non-military style) that I loaned to a friend and it failed at traffic lights. Fortunately it failed when he was starting, not when riding. No photos, because this was before digital cameras.

The steering geometry is unusual by modern road bike standards, but common with old work and touring bikes. The low trail reduces wheel flop, and wide low pressure tires provide the stability. These bikes are meant for heavy loads, slow riding and gravel roads.

The bike is very probably from 90s, even though the one piece crank was already obsolete at the time. I recall Helkama using that logo at the time, and the Rautaruukki sticker is a response to to "Tange Hi-Ten" stickers that were appearing on MTBs at the time. Rautaruukki is a steel foundry most known most for building supplies. They have specialized in high strength steels in 2000s, but those are not marketed for bicycles.

The white paint on rear mudguard was required in Finland at some point. I don't know the exact history, but I think the rule was removed in the 70s. This one looks like hit has been painted afterwards.

I do not recognize the logo on register plate. My guess would be that it has belonged to a saw mill or pulp mill. The old logo for Forest Administration that you can still see in national parks is a bit similar, but not the same. The broken frame lock and spray paint imply it was stolen at some point.