What is an asymmetric wheel and why would you use it? Campagnolo advertises the Khamsin Asymmetric Wheel:

What is an asymmetric wheel and (given that we expect wheels to be symmetrical), why would one want an asymmetrical one? How is it related to dish?

The "asymmetric wheel" terminology is a little misleading. This particular wheel has an asymmetric rim.

Any bike with a rear derailer setup will have an asymmetric rear wheel, because the gears take up space.

The usual way to handle this is that the spokes on the gear side have less of an angle (closer to vertical) than on the non-gear side. (That is, they have different dish angles) Since an angled spoke also pulls outward slightly and the horizontal forces need to balance, the gear side spokes also have higher tension.

That more vertical angle and higher tension makes the gear side weaker. Combined with pedaling force tending to apply more on the gear side, the most common spoke failure is on the gear side of the rear wheel.

In other words: the gear side of the rear wheel is the limiting factor in the strength/lightness balance when engineering and building a rear wheel.

When a rear rim is asymmetric, what that usually means is that they've moved the line that the spokes all connect into away from the gears. This allows the angle to be slightly further from vertical while forcing the non-gear side a bit closer to vertical. That is, both sides will have closer to the same spoke angle. That means that the tension on both sides can be closer to matching.

Having the dish angle and tension closer to matching allows for the hub and spokes to be stronger and/or lighter. (but may require strengthening the rim slightly)


damage to carbon road frame at the seat stay and drop out junction I just had a crash due to hitting a dog. My carbon fiber frame now has chip the size of a dime at the junction of the seat stay and drop out on the drive side. Should I be concerned about frame failure now or in the future?

Anytime you are in a crash I think you need to be worried about damage to the frame and future frame failure. Unfortunately it's very difficult for a lay person to inspect and evaluate damage to a carbon frame. For this reason I would suggest that you take the frame to a reputable bike shop and have it inspected there.

You should also remember that carbon fiber absorbs water, so the chip in your paint/gel coat get should be fixed ASAP, as water damage can cause a corrosion cell to form and the frame to fail.

Assuming the frame passes the inspection of the bike shop, you can touch up the damage with clear coat touch-up paint, or some people have used clear fingernail polish.


What tyres will fit this ebike rim? Out of an impulse buy - I now have a complete ebike kit with battery.
Originally I wanted this to be put on a mountain bike but upon seeing how little the rim is - I don't think any mountain bike tyres will fit in there.
I measured the rim (where the tyre will go) and it was roughly 2cm, slightly less in fact, does that mean that this kit is designed to go on a road bike/hybrid bike and only that?
The diameter is 26 inches - any help appreciated thanks

Presumably you have purchased an eBike kit with a in-wheel motor, so you have a wheel but you don't know what size the rim is. What did the kit specifications say about the wheel? Is there a marking on the rim?
An approximately 20mm wide rim is wide enough for mountain bike tires up to 60mm / 2.25 inches in width.
The bicycle wheel diameters in common use are:

ISO/ETRTO 622 - 622mm rim, known as '700c' on road bike, '29 inch' on MTBs
ISO/ETRTO 584 - 584mm rim, known as '650b' on road bike, '27.5 inch' on MTBs
ISO/ETRTO 559 - 559mm rim, known as '26 inch' on MTBs

The ISO/ETRTO number is the diameter of where a cincher tire mounts on the rim. The MTB sizes refer to the nominal diameter of the whole wheel with a tire installed, not the rim diameter. You can  measure you wheel rim to figure out what you have. 26 inches is 660mm so I think that measurement is an error.
Bear in mind that bicycle frames are designed for a specific wheel rim diameter. You can't put a 622 wheel in a frame designed for a 559 wheel. You also need to pay attention to the hub width, wheel attachment (nuts, quick release etc) and rim vs disc brake when considering frame compatibility.


Remove visible thorns etc from tyres equipped with inner tubes with sealant liquid? Running with inner tubes equipped with sealant liquid, should we remove visible thorns etc or not?

You should always remove the thorns as soon as you see them. There's a good chance that if you're diligent about it, you'll get them before they even get through the tyre to put a hole in the tube. For ones that are already embedded deeply enough in the tyre to puncture the tube, removing them will prevent them from making the hole bigger than it already is.

You should remove them carefully in a way that allows the sealant the best chance of fixing the puncture. To do this, begin by resting the wheel vertically such that the thorn is at the bottom, near the ground. You then leave it like this for a few minutes. Gravity will cause the liquid sealant in the tube to pool at the bottom, near the thorn. Once you pull the thorn out, the sealant should plug the hole almost immediately, but it's still best to leave the wheel with the puncture at the bottom for a while for best results.


Frame/fork compatibility I have a singlespeed/track geometry frame and I am after a fork that matches it.

Besides the diameter of the steerer tube (it's 1 1/8"), what should I be looking for in the fork specs to be sure about compatibility?

EDIT: Let me be be more specific about the actual fork+frame combination that I want to assemble:

Fork (Alpina UD Carbon Track Fork)

Droput lawyer tabs: No
Fork length Axle - Crown (cm): 36
Headset type: Integrated
Rake (mm): 35
Steerer diameter (inches): 1 1/8

Frame
http://ride2rock.jp/products/bike.php?id=31411

Frames are made with specific axle to crown and fork offset (rake) numbers in mind for the geometry to be as intended. There's typically a common, mainstream set of numbers, give or take a few mm, for each genre of bike, but manufacturers can and do go outside of them.

Typical for track are offset numbers around 40mm. It's pretty common to see track forks with the smallest axle to crown numbers of any 700c forks (call it 370ish although there's differences in how people measure), correspondent to the tight clearance, but it's not universal because there's variance in the height of the crown itself, plus a bunch of SS bikes are now intended for brakes other than short reach road calipers.

If you know it's a level top tube bike and you have no other information about what axle to crown it wants but you have a protractor and a yardstick, you could model it in CAD or otherwise do the math to figure it out. If it's sloping top tube and you have no other information about it, you're somewhat shooting in the dark, although you could still put the frame in CAD, assume the headtube angle is typical for its size and genre, and use that as a reference point to get your axle to crown. Even if you're a little bit wrong in your guess, that will still result in a bike with handling that's about right. (Note that there's a whole world of debate about front end handling geometry and there's plenty of room for different preferences and theories.)

Finally with integrated/internal headset bikes there's the mostly aesthetic consideration of the smoothness transition/line between the headset and fork. (Mostly because some would argue there's an aero difference.) There are some trends there and plenty of manufacturers that do it certain ways, but no broader standards or rules.


How to pick the correct lock ring removal tool I have an (admittedly cheap) lock ring removal tool which is bundled with equally cheap red-handled chainwhips commonly sold on eBay:

This tool works great for installing and removing Shimano cassettes.  I really like the fact that it has a 1/2" socket adapter so I can snap it on to my torque wrench.
I now have a bike with disc brakes and want to swap wheels. The aforementioned tool has the correct number of splines for the rotor, fits but only goes down about 1mm into the hole, so I'm unable to remove the rotor lock ring because there's not enough purchase.
I'm looking at either Pedro's 6460010 (lock ring tool with no center pin) or the Shimano TL-LR11. I'd like to avoid the Park FR-5.2 since it requires a 1" socket to fit on to a torque wrench, making it far too easy to fall out. The TL-LR11 says it is specifically for the SM-RT10 and won't fit standard center locks, so I may be barking up the wrong tree. I have SM-RT70S rotors
Which of these tools would best suit my needs or should I look for something else?  I'm also considering switching to external lock rings that require a BB tool, but would like to be able to remove the existing rings myself and/or use this tool help out friends in the future.

The limited engagement you speak of is a quirk of some hub and Centerlock lockring combinations. It's annoying. You are correct that if you want, you can probably eliminate the issue with the kind of Centerlock lockring that uses an external BB tool. To my awareness there's not really another way; when I've seen this it's not a tool compatibility problem as such, but the hub has something going on that would block any conventional lockring tool from getting in far enough.
To do it with the tool you have, use a lightly clamped QR skewer to hold the tool on, and then turn it with a big adjustable wrench. That should be able to overcome the limited purchase if the end of the splines are still in okay shape from prior attempts.


In what ways is a dual pivot brake better than single-pivot? How exactly is a dual pivot brake better than single pivot?

Is it the travel, mechanical advantage, or what?

The main point of a dual pivot is the mechanical advantage. Since the individual pivot for each side of the brake is optimized for a greater lever length, you end up with a greater pressure of the pads against the rim.

Also, since the pivots are cleverly positioned (in my opinion), you end up with a compact, light and strong overall structure.

The downside would be tire clearance, which is not big problem on road bikes. On mountain bikes, V-brakes provide very good mechanical advantage with a very good clearance, but with a less compact structure.


How many watts is a good push worth? The other day as I commuted home a stranger gave me a helpful push as I approached the top of a steep hill. It was wonderful, and I immediately wondered if this is what an e-bike boost would be like.

Is there some way to calculate how many equivalent watts a nice push produces? Very curious to know if it's on the low end (20 or so) or the high end (200 or so).

The faster you're going the more power you get out of a given amount of force or "push". Ad bsdl says, power = force times speed, so the same force at a higher speed requires or provides more power.

Going slowly up a hill even quite a strong push doesn't cost much power. A 200W "push" at 10kph will take you up most road hills with little to no pedalling, since that's all the power that's required. A 200W push at 70kph on the flat is noticeable but only just, because 200W requires less force and the rider is already having to put out 500W or so to go that fast. The extra 40% power also has a reduced effect since air resistance goes up as the cube of speed. Adding means 1.4x as much power but the speed change is roughly 1.4^1/3 = 1.11, so you'd only go ~8kph faster or 78kph.

You can experiment with this if you are the one giving the push. The relationship between how fast you're going and how much effort your legs have to put in for a given push force is quite perceptible even at relatively low speeds. It's very easy at a moderate speed to push someone and find that you're going backwards relative to them quite dramatically, but without their speed changing much at all. They'll be saying "go on, push" or "that did nothing!" while you're sprinting frantically to catch back up to them.


How bad is this fire damaged alloy frame? I got this Shimano Ultra groupset bike for free, all I need now for it is shifters as the carbon and rubber melted in them and the original seat.

But now I am wondering if I can get away with it, I don't want the top/down tubes to brake off the head!

The cable adjuster on the down tube is a bit melted on this one if you zoom in:

Everything works great (Not to say I know if there's a good amount of lube in the head tube but it turns fine)  but what do you guy think is it too dodgy to keep aluminium that has all that darkening round the welds?

I know a lot will say biff it and I should at least get a new stem but please give me some disclaimer-ed thoughts for a proper like myself just wanting a bike that has better gears than Shimano tourney!

EDIT:

This is what concerned me: http://forums.mtbr.com/tooltime/repairing-fire-damaged-bikes-689507.html They tell the guy to ditch a bike with no viable damage!

It would be interesting for example to know what temperature it takes to melt the old bike seat completely of the metal guides and curl the shifter carbon leavers!

I've done a bit of aluminum anodizing which requires annealing (softening) of the metal. This happens at about 650F. You mentioned the drop bars being melted so I suspect the top tube is likely annealed and won't have the same stiffness as it's suppose to. It may flex more than it should and may cause other parts to flex more also.

The head tube bearings were also mentioned and should be checked. I also wouldn't trust the seat post.


Which tires (and rear fender?) for Bianchi Metropoli Uno hybrid bike I have a Bianchi Metropoli Uno XL (frame size 55cm). As you can tell from the attached pictures, the back tire (37-622/700x35C) needs replacement (at least I would say so as the profile is barely visible anymore).

I use my bike mostly for commuting. My way to work is just under 20 km, with a third on flat gravel roads and the rest on asphalt. I cycle all around the year, except if there is snow.

Would you have any advice for me? There seems to be a rather large choice. Among this list, would you have any recommendations (e.g. the Schwalbe Energizer Plus)? Can I eventually use the same tire also for the front wheel (which I think is less urgent to replace)?

PS. As you can see on the pictures, my back fender is broken. Would anyone know of a compatible spare part?

[

Fenders/Mudguards are more important on a commuter bike than any other style of bike.  That's because it helps keep you clean for wherever you're commuting to.

So the features you're looking for in a mudguard / fender are

Length - a rear mudguard should stop water and muck flinging off the back tyre from hitting you or your bags.  To do that, the rear mudguard should be long enough to finish at-or-below the level of your rear axle.  The front guard can be even longer because its job is also to protect the bike's BB area from road muck.  Its not uncommon to see front guards dropping even lower.Some have a leather or rubber "curtain" or mudflap that continues down where the guard stops, increasing its effective length.  Also, the front of the rear mudguard should ideally finish below your BB.  The longer front stops road-water from hitting you in the face while turning.

Example of an overall excellent design for mudguards. The silver L brackets at the top go into the stackup of your rim brakes, either on the nut or on the brake side.  So they will require a bike frame with a brake bridge.   Also see the two stays in a triangle.  They help support the guard.  Some designs simply flap in the breeze, which lets them rub the tires but does look slightly more sporty. The guard is also a great place to add reflectors, sticker-reflectors, or lightweight lights.

Good front guard example (note its not well-fitted to this bike, because the stays are curved, and there's an inconsistent gap between tyre and guard, and its mounted so the front edge is too high... it should bend down more on the leading edge.)

Clamping system - you need to inspect your dropouts and look for a spare hole for mounting the stays. Examples:
 The two yellow holes to the left are for stays.  Some bikes might have one, two, or even three holes.  Some have none.

For your bike, I can't see any but they may be hidden by the trailer mount.

If you don't have holes for mounting, you'll need either P Clips which look like this:
Or you may need to limit your mudguards to those which attach to the stays.  Downside of these is there's a lot more unsupported length so they flap a bit, and don't last as long.

Notice this one is too short in the front, and should have a second piece that goes from the brake bridge down to the bottom bracket.

Width - a wider tyre needs wider guards.  You should have guards that go further sideways than your tyre so they can catch water flung.
Material and colour - its completely up to you.  Steel, Aluminium, and plastic are the two common materials for guards, and you can get combinations like "chromoplast" which is a chromed plastic, being lightweight.  Some people have made wooden guards, but they tend to have one curve whereas a good guard is curved in two directions to follow the tyre.
As for Colour, whatever suits your bike.  Black, bright chrome, and matt chrome are common, but you can paint them any colour you want.  Matching or contrasting your frame to suit your taste.

Less-good mudguards there are times where compromise is required.  You should avoid "ass savers" because while they're better than nothing, they're not anywhere near as good as a full guard.

There are some designs that attach to your saddle - I have one and road water still drenches the back of my thighs.

Motor-cross style - these are intended to stop mud from packing up between the tyre and the fork bridge on a MTB.   Instead they help ease mud through the gap to be thrown off.  No practical use on your commuter.

Further information and reading here:   Very basic mudguard question and https://www.sheldonbrown.com/fenders.html


New chain, new cassette, new trainer...new noises I recently got a Tacx Flux 2 Smart trainer (because lockdown) and decided to get a new cassette and chain as well, since I won't be doing any riding anytime soon and would like to keep everything nice and clean in the house.
I installed the cassette on the trainer,checked I was using the right adapters for cassette and QR, and then measured the new chain against the old one (they are the same KMC 9 speed), making sure they were exactly the same length. I then installed the chain with the supplied quick link, making sure it is routed the right way through the jockey wheels.
However, I now get a very clear droning, grinding noise and perceivable vibration when in the smaller 3 rings. The noise almost disappears when in lower gears. The shifting fine though, and I can get shift in all gears.
I have no idea what can be wrong and it feels almost like the chain has a hard time slotting into the teeth of the chain rings. Almost like the each roller slightly hits every tooth before grabbing on. If I had to describe it in an onomatopea, it would be a grindy "RRRrRrrrrrrRRrrrRrRrrrRr"
What could be the cause of this? Is it just because the chain and cassette both need to be bedded in? Is it lubrication?
** UPDATE **
I finally managed to ride the bike outside and cannot reproduce the same noise or vibration. It seems that the issue is with the bike one the trainer.

I got the same with my new COVID-Kickr, in my case it was simply the alignment of the cassette/trainer with respect to the frame/rear-derailleur/chainline.

For whatever reason the usual stops in the frame that ensured same/similar alignment when mounting the wheel just wasn't quite right for the trainer (skewer QR system here).

It's hard to notice as without the wheel you can't check the placement with respect to the front of the chainstay (or brakes in terms of 'roll' misalignment) as you would with a wheel (assuming it's correctly dished).

If you're grinding in the bottom 3 then I'd suggest your first tweak would be rotating the trainer slightly counterclockwise (looking down) with respect to the frame, this amounts to relatively more rearward in the left dropout, and/or more forward on the drive-side. If it's better then that's a win, if it's worse then go the other way.

Either way it's helpful to get someone else to ride while you investigate (wish it were so easy on an actual bike huh!)


Is it bad to keep hydraulic brakes engaged for many hours? I find it easier to park my bike if I can remove one of its degrees of freedom, for example, prevent the wheels from rotating. An easy way to do this would be to strap one of the brake levers down.

This would be for around 8–12 hours, 5–6 times per week. I have hydraulic disc brakes. The bike would be upright.

I have a feeling that this is a bad idea. Is it? And if so, why?

Short answer?  No, it will not generally cause you a problem.  This is actually a common method of parking a loaded touring bike.

Don't over tension the brake lever.  Remember that a hydraulic lever doesn't require excessive force to have power at the brake.

A simple 6mm rubberband wrapped over the lever and handlebar should accomplish your purpose.


Changing one of the chainrings on SR Suntour NEX crank? I have a SR Suntour NEX (42x34x24) crankset and got my system really bad recently.
But as I've used the second (34) chainring most of all I would like to replace only this one.
Is it okay? Does my crank allow it?

Thanks.

The Suntour NEX cranksets are marked as "Interchangable Chainring Design" by Suntour, while the XCM's are marked as "Full Interchangable Chainring Design".

This means that you can replace the big ring on a NEX crankset, but the middle and small ring are one piece. So, if you want to replace the middle chainring, you have to buy a whole new crankset (or somehow source the middle and small together). Given the NEX is a fairly low end part [~ 30 USD], another crankset is likely a better idea [ You can pick up a Shimano crankset or similar with all chainrings replaceable for around 50 USD ]. Note that  a new chainring would have been likely ~20 USD if you could have replaced it.

Also note that you can go a good while with a "worn" crankset provided the teeth aren't mucked up too badly (e.g. bent), so "suck it up and deal with it" may be a good option depending on what state the crankset is in.

The crankset replacement procedure is here - you may need some tools you don't own.


Repair frame with crack by seatpost clamp Is it feasible to repair a crack in a frame around the seatpost clamp? Being an aluminium frame I understand soldering is problematic. It doesn't matter if seatpost is fixed in place as per a solution involving epoxy/some kind of wrap etc.

Is it feasible to repair a crack in a frame around the seatpost clamp?

feasible:
1. possible to do easily or conveniently.
2. likely; probable.

It is possible to repair an aluminum frame. It is not easy or convenient.

It's all about how much effort/money you are willing to put into this project.

Finding someone with a gas tungsten arc welding rig who would be willing to weld on your frame is one thing. Finding someone who knows what they are doing is something else.

Here is a discussion on a welding forum with an intelligent answer on aluminum bicycle frame repair. Here is a snippet of the conversation relating to repairing a frame:

  Any repair should be made via gtaw (tig-heliarc) by an EXPERIENCED welder.  If the frame is truely 7005 then 5180 would be the filler material of choice.  This will allow the frame to undergo heat treatment to restore it to its original condition.    If the frame is actually a t6 alloy more than likely you should use a 4643 filler which again will allow heat treatment.....if you wish to repair without heat treatment use 5356 which will work on either alloy but without heat treatment it will never be in the condition it was when produced.

The most feasible solution is to see this as an excellent opportunity to upgrade.


Seating issues with plastic wheels On a Thule Chariot Trailer (back when sold as Trek), it came with the plastic wheels.  I got it second hand so I assume the tires are stock.  The tires are rated for 55 psi, but they slip off the wheel and cause blow outs (both out and about as well just sitting in the garage).  This happens on any of the wheels.  I can not find any damage to the wheel or the tire, so my current work around is using around 35 psi.

Has my tires aged too much?  It has been garage kept.  While the tires do have some cracks in the tread, they hold up really well.  The sidewalls are kind of stiff so I can stroller around with it easily without air (these wheels have blown out on me in public before).  I notice that the tire is a bit more shiny than any of my newer ones.  Would replacing the tires with new ones prevent this from happening?

Is a wheel change in order?  I see that the current models use conventional wheels.  The plastic wheels don't really bother me personally.  They are the side post quick release, with the release mechanism on the trailer itself and not like a push button in the wheel hub.

It's the plastic wheels.  Most mag(composite or plastic) wheels are only rated for 40 psi, no matter what the tire says.  No need to change out for metal wheels as long as you are happy with the trailer.


Alfine 8 crunching/grinding in highest gear I have recently bought a bike with an Alfine 8 hub and it was working well for the first week or so. Then there was a couple of gear drop outs whilst I was riding so I made sure to line up the yellow lines at the back.

Since then I've experienced a horrible noise coming from the lowest (easiest) gear whenever I put any reasonable weight on it. If I use it on a perfectly flat surface and peddle slowly then it's quiet but as soon as I try to pedal with any speed the hub starts making this grinding/crunching sound.

Moving the lines slightly OUT of alignment actually reduces the noise but causes problems with other gears.

Should I be sending this hub back to Shimano?

I've attached an image of my yellow lines lined up.

I was all set to return the Alfine hub to the manufacturer and when I went to take it off I realised the wheel nuts were loose. Tightening the nuts solved the problem. It seems the hub not being fixed in place was causing it to be moved in the wrong direction and shifting to the lowest gear was pulling the mechanism too far inside the hub.


Is cycling in the Netherlands without a helmet safer than cycling with a helmet in the USA? We moved to Netherlands and no one seems to wear a helmet. My teenage child did have a helmet but said she lost it. When my wife wanted buy her a new helmet, my daughter said she will refuse to wear it. This ended up in some family drama between them.

My daughter ended up saying that it is safer to cycle without a helmet in the Netherlands, then with a helmet in USA. To end the crisis, we agreed that she does not have to wear a helmet if this is true. (My wife expects it to be false) But I am not sure, as I read once that the safety of a helmet is generally overestimated (and there is also some risk-compensation). Hence my question is:

Is it true that cycling in the Netherlands without a helmet is safer, then cycling with a helmet in the USA?

Apart from that my daughter claimed that the health befits of cycling outweigh the risk by far. Is this true?

Please give scientific evidence if possible.

There's a simple answer to the question you didn't actually ask: in the Netherlands cyclists who wear helmets are much more likely to be hospitalised than those who don't

Although the Netherlands is probably the safest country in the world for cycling, helmet wearing among Dutch cyclists is rare. It has been estimated that only about 0.5 percent of cyclists in the Netherlands are helmeted.
However, according to Dutch Government data (Rijkswaterstaat, 2008), 13.3 percent of cyclists admitted to hospital were wearing helmets when they were injured. Why does wearing a helmet appear to increase the risk of being injured so substantially?
The answer is probably related to another statistic. Of the injured cyclists wearing helmets, 50 percent were riding mountain bikes and 46 percent were riding racing bikes (Rijkswaterstaat, 2008). In other words, most helmeted cyclists in the Netherlands are engaged in a competitive activity, with very few making utility trips on the traditional style of Dutch bicycle.

I can't find a useful answer because of that. I couldn't find statistics that answer "of the less than 1% of utility cyclists who wear helmets, how many were killed or injured"?
Of course, having so many people riding bikes on the roads also means that of the people killed on the roads, a high proportion are cyclists (about one third). The Netherlands is also the safest place in Europe to use the roads (45 deaths/million pop, cf 145 in Greece which is the worst in Europe and 147 in the USA).
What that means is that in The Netherlands about 185 cyclists die every year compared to 700-odd in the USA (~4x as many, thanks whatsisname). There are more than twenty times as many people in the USA... but more trips by bicycle in the Netherlands. You're still safer there than any inhabited part of the USA. You're safer on a bike in The Netherlands than in a car in the USA, even just looking at immediate crash danger rather than life expectancy (the lifetime risk of death remains 100%, obviously).
There are some amusing results of that:

After a recent decline in the murder rate, you are now fractionally more likely to die while biking than to be murdered in the Netherlands!

In Amsterdam, you're still more likely to be murdered, though.

You're also more likely to die by murder in the U.S. as a whole than by biking in the Netherlands.

You are also more likely to drown here than either die biking or be murdered, especially if you are a child.

My suggestion is to look at it the other way: if you-the-parents insist that your daughter wear a helmet while cycling, will she keep cycling? Will she be unhappy that her mother would prefer her be socially ostracised than even try to fit into the new culture? Will she just observe that her parents are failing to assimilate and reject them, rather than everyone she knows?
Also try flipping it - how would your wife deal with someone who moved to rural USA and didn't want their daughter to learn to drive? Or insisted that she only travel in the Smart car, since that's the safest small car and it's what her parents had back home in the Netherlands?


Can I replace Shimano 105 5500 shifters and derailers with new Sora R3000 ones? I have a 2000 Klein Quantum
(this one, 2x9 speed: https://www.bicyclebluebook.com/value-guide/product/45657/)
My shifters have been replaced once already with used 105 (also 5500), but now they have a lot of issues and I would slowly like to upgrade the whole groupset.
Can I start by switching out the shifters and derailers with new Sora R3000 parts (also 9 speed)? Or would I have issues with the brakes/crankset/etc?
This would put me back on the road while I save for the rest.
Thanks for any help, this is my first time here.

Can I start by switching out the shifters and derailers with new Sora R3000 parts (also 9 speed)?

All Shimano 9-speed parts use the same derailleur pull ratio (except the front derailleur pull ratio can vary between MTB / road components). Thus, you don't even need to change the derailleur, just changing the shifters is enough.
The STI levers are short-pull levers compatible with any cantilever or caliper brake. They are not compatible with V-brakes. As your old STI shifter/levers were short-pull too, no changes there.
Just be sure to select the Sora 2x9 parts instead of going for Sora 3x9 parts.
I'm not sure what issues you have but as the STI levers are expensive, please be sure to eliminate the possibility of issues coming from some other parts first. Perhaps your bike needs new inner and outer cables instead of needing new shifters?


Change wheels diameter from 28" to 26" I have a regular single speed pedal brake bike with 28 inch wheels. I would like to switch it over to 26 inch wheels. Would this cause any problems, or can I just easily change them over?

It can sometimes be done, but usually you will run into problems.

Major problems:

Brake compatibility: Rim brakes do not reach the rim in its new position. Disc, drum and coaster brakes are not affected.
Pedal clearance: Pedals will now be closer to ground and will hit the ground if you are not careful when turning.

Minor problems:

Steering will be different because the geometry changes.
Gearing will be lower because smaller wheel circumference.
If you are doing this so that you can have wider tires, they do not necessarily fit into your frame.
If you are doing this to have a smaller bike, it does not work. You still have the same size frame, just closer to ground.


Bike position - Town bike I have found a lot of documentation on the internet on how to chose the correct riding position for a mountain bike or a road bike.
The thing is that my bike doesn't fit in those classes.

My bike is exactly this one

I want to know what is the best riding position for my bike.

Riding position depends on different things, of which the bike is just one. The distance between the saddle and the handlebars combined with the the length of your body and your arms limits the options you've got.

But the kind of cycling you do is just as important. When riding around town, especially in crowded places and/or when not being in a hurry the best thing to do is to sit straight up. It allows you to make short turns, it's easier to stop, it's easier to look around you and allows you to talk to the person riding beside you. (With some practice you take you hands of the handlebars and still steer with just your balance and stand still on your bike without getting a foot on the ground). You need your saddle to be somewhat below your handlebars, but still at a height where you don't have to bend your knees to far. This basically is the way the Dutch cycle around town. It works when you treat cycling as an alternative to walking around instead of a sporting activity or a way to go fast. (Because, when moving around on your feet you're not running all the time either).

Judging from the image your bike seems suitable for that, the pedals seem to be slightly more forward then a road bike, which will push you a bit straighter up anyway.

If you want to go faster you can lean more forward, but depending on the length of your body that might get a bit cramped. If that's an issue you could but an armrest like this on the handlebars allowing you to lean further forward.


Did any manufacturer ever try using more, but lighter spokes to minimize weight? Wheels generally used to have more spokes.

As technology improved and markets changed, manufacturers have taken to making wheels with fewer (and often heavier spokes). I've been told this comes at the expense of having a slightly heavier rim to maintain strength and stiffness.

I realize that aerodynamics generally has more impact on performance than shaving a few grams, but I was wondering if any manufacturer ever tried making wheels with more, but finer spokes, perhaps to save on rim weight rather than spoke weight. Was this ever done?

To the best of my knowledge, and my ability to find reference in any old catalog or tech manual, no, that concept has not been tried on a commercial scale at least. It may have been tried on a local scale.

I don't have the math to prove it, but I suspect the balance point between how thin the spokes would need to be to reduce the weight enough to offset the additional weight of more spokes, and the tensile strength those spokes would require to maintain the strength of the wheel without breaking would prevent any weight benefit from being gained, and I know that spokes thinner than 1.8mm have a far greater likelihood of breakage. The butted 2.0/1.5mm spokes which were popular in the late 90's for XC racing wheels proved that to me.

Perhaps we could get the Math or engineering SE guys to comment here?


What first bike to buy? I'm going to be moving to a semi-urban area in a few months. I'd love to buy a bike to be able to travel around the town.

I don't want to spend too much money. I'd say the best < $300 can get me.

What kind of bike should I get, and what would be the best way to go about this? Visit a local bike shop? ebay? Craigslist?

I would suggest first deciding what kind of bike you'd like. Road vs. Mountain vs. Hybrid.

Road - more aggressive positioning (lean more forward) for aerodynamic benefits. Thinner tires.
Mountain - more upright, sturdy/heavy. Wider tires for offroad
Hybrid/Cross - something in between. Usually road type bike with clearance for slightly wider tires.

In your case I would suggest a used 90s steel mountain/hybrid bike. There are millions of them around and all over craiglist. Make sure the bike fits well (ie. you can adjust the seat/handlebars sufficiently to be comfortable).

A bike such as this (mountain/hybrid) should also have lots of eyelets for attaching fenders/racks/baskets to carry stuff.

Craigslist is a good way but if you're not very familiar with bikes you should try to find a friend who can help. That way they can go with you to look at any used bikes and make sure it's decent. If that's not possible, hopefully a local bike shop can help and not try to up sell you. There are many, many used bikes in your price range so don't let a shop try to talk you into a new bike.

Another option is to ask local bike riders you run into what they like about their bikes and let them point out stuff. I don't think there's a serious bike rider who wouldn't spend hours discussing bikes.

Hope this helps.


Frequent blow outs in the same location I keep getting blow outs in my front tube and always in the same location: right next to the valve stem. The blow outs look like:

On this same tube, there is wear on exactly the other side of the valve stem.  I have checked the tire and the wheel and there doesn't appear to be anything sharp enough there.

What can cause this? I suspect it's something that I'm doing. I'm tired of buying new tubes, as I hear these flats cannot be patched. If it matters, it's a presta valve and I usually inflate to 110 psi, the maximum.

Check inside the rim at the point where the punctures occur.

Is the rim tape intact?

Does a spoke push through when weight is placed on the bike? One of my friends had a problem like this, and it turned out that when he sat on the bike his weight caused the end of a spoke to push through the rim and puncture his tyre.


Wearing short sleeved merino by itself? I heard merino is for cool-cold days. Maybe I heard it wrong.
Then I thought people use it for baselayer (something you wear under your jackets).
But it seems it's not the case based on some reviews/images I see.
So What's the point of wearing merino shirt itself?
Do people wear them in hot days as well?

Merino is an anytime material . It’s core property is that the fibres are very fine and structurally more complex compared to a more general wool product.
You can wear it on a hot day to feel cooler as the fibres will absorb sweat and keep it next to your skin or on a cool day to keep you warmer as it’s very insulating due to a hollowness in the fibre.
It doesn’t gain as much of a body stench compared to an artificial fibre and can be worn multiple days in a row without being too offensive to you or other people.
When a 100% Merino shirt has worn out you can dump it in the compost or use it to line a plant pot.
You’re right in that people use it as a base layer as it works well next to the skin and on hot days you will get more UV protection.
It is more expensive compared to other materials but the benefits are high for the investment cost. I haven’t worn anything else for cycling or any outdoor exercise for a long time.


What is the name of the part by the right-hand pedal on to which the chain grips? There's a part common to all bikes that resides by the right-hand pedal that holds the front sprockets upon which the chain grips?

I'm aware that this part contains the sprocket or sprockets on to which the chain grips. I'm aware that this part will often contain the right pedal arm.

I'm not aware of the name of the part itself. What is this called?

I'm asking as I have one that is slightly bent. I'm looking for the correct terminology to better find out how one might best return this part to its non-bent state.

The part to which I'm referring look like this:

The entire assembly is called the crankset.

The ring with the teeth is called the chainring.

The crankset consists of the crank arm, the spider and the chainrings.
The chainrings bolt onto the spider which is the multi-armed piece connected to the crank arm.

The right crank arm and spider are often one piece. Lower-end cranksets are forged or riveted together, while higher-end (like the one shown in the question) are bolted. With bolted cranksets one can exchange only the chainrings; with monolitic ones the whole assembly has to be replaced once the chainrings are worn.


How to disassemble SRAM PG-950 cassette It seems to me that SRAM used not rivet to hold all the cogs in one place, but long screw. This screw looks like a hex one, but I tried hex keys I have and I didn't find a match. Unfortunately the head is so small I cannot be sure it is hex in the first place (and not for example pentagonal).

So my question is am I correct with the "screw lead"? If yes, is it a hex one indeed? And what size?

I am asking to avoid drilling it through. Screw is always nicer to work with also because I can screw it back.

Hex bolts on bicycles are usually metric, and it seems that the bolts holding the cassette together are too. Inch based hex key sizes fall just in between so that none fits.


Faster with lower center of gravity? If I bend my torso toward the top bar, lowering my center of gravity, will that alone help my bike go faster?

Leaning forward will help you go a bit faster, but not not because of lowering your center of gravity (more properly center of mass).

Leaning forward reduces your frontal area, which reduces air resistance which potentially enables you to go faster. However, there are many different factors that come into play that effect air resistance - style of bicycle and handlebars; hand, arm and head position etc.

Personally, I find that leaning forward reduces the power output I can produce, so adopting an aerodynmic position only makes sense on fast downhills where the aerodynamic benefits exceed the loss of pedaling power.


How do I inflate this bicycle tire valve? I inherited this bike with this funny looking stem. Is this broken? How do I inflate it?

This is what's known as a Presta valve. It doesn't look broken, it looks like it is all there and the valve is in the open position because the captive nut at the very tip of it has been unscrewed.

You can test if it is working by just nudging the end of it upwards briefly, some air should escape. This is good to do before inflating anyway to see that the valve has not become stuck before you pump.

You need a Presta compatible pump (some have a double head and some can be converted), or a small brass 'Presta valve adapter' to convert from a normal car valve (Schrader) type pump.

A 'track pump' is a bicycle specific pump that typically has a head that suits both type of valve and is available from all good bike shops.

Here is an image showing operation of my preferred style of pump head, that I found online on multiple sites with no attribution (but probably Topeak themselves):


Is it common to own two MTBs for different weather conditions? I'm newish to cycling, so I apologize if this is a stupid question... Does it make sense to have two MTBs -- one for dry weather and another for wet/winter weather? I'm doing both paved and dirt trails.

I'd like for my current MTB (a 27.5x2.0 hardtail Specialized) to be used in dry weather since it already has slicks on it. Then I'd possibly like to have a second MTB with much wider tires (e.g., Trek Roscoe 7 @ 27.5x2.80) for the rainy/wintry weather. I don't want a fat bike per se, but something with wider tires so I get more traction, and likely studded tires for the winter.

I'm not riding everyday because I'm afraid of slipping in the rain, and I'm kinda lazy about swapping tires. I know it only takes like 5-10 mins to swap tires, but I don't even know if it's safe to be swapping them all the time (e.g., if it destroys the rubber over time). Also, having an extra set of wheels can be expensive considering my current MTB is only $450.

This can not be answered objectively for all people. Your current conditions, budget, space availability and preferences all play a role in such decision.

The advantage of having just a spare wheel set is space saving. If they are for disk brakes then they are the fastest to swap.

The advantage of having more bikes is (more bikes! Duh!) you can have them tuned for different purposes or types of riding. Even the same model of bike you can tune more for aggressive climbing and other for comfort (long rides) or for aggressive downhill practice. Switching from one bike to another is less hassle than having to re-tune the bike every time you decide to go for a different type of riding.

Another advantage of multiple bikes is that one of them breaks in such a way it is difficult to repair, you can just ride the other one while the broken one is under service or waiting for spares to arrive.

Some people do have a bike for training and other for racing. I do not carry that practice, so I do not know the specifics, but I'd think that they have the top-level bike in a safe place while the other one takes the risk, wear and tear of routine training. The bikes would have very similar configurations but maybe the training one is heavier, lower spec'd components and maybe use on that one the tires that aren't new but still have some use life on them.


Why is standing more common on hills than on flats? We all know that standing on a hill feels better than standing on a flat.

Even pros seemingly only stand up for hills (not counting sprints).

What causes this?

Here's what I've thought of so far:

Often you can ride up a hill without shifting out of the gear you were using before. If you were to stay seated, you would need to shift down.
For a long time (road) bikes had such high gears that you had to stand for many hills. That's not the case anymore though, so maybe it's a moot point.
When you're on a hill, the bike is tilted backwards. This makes it easier and more natural to stand up, because the bar is "higher" and more reachable than it would be otherwise.

But I have a feeling there's more to it than this. These reasons are not significant enough to explain the difference I can feel, or the way pros behave.

Because in the flats you reach higher speeds, and at those speeds aerodynamics become very important, so exposing more of your body to the wind is a drag.  The standing in flat is then limited to sprint bursts, or just used to give a little rest to your legs and buttock. Whereas going uphill is usually slow so the power advantage you may get standing is worth the trade-off for worse aerodynamics.


How do I know when to replace my tires? The treads on my road bike's 28C tires are almost completely gone—they only persist along the shoulders of the tire.  Do the treads matter?  What is a good indicator of when the tire as a whole needs to be replaced?

The tread on a road bike's tires is really quite unimportant and purely cosmetic.  Road bike tires have tread patterns because they sell better, not because they perform better.

Here's some questions to ask to decide about replacing a tire:

Can you see any of the fabric?
Are you getting flats more easily than you used to?
Is any part of the tire bulging out or lumpy?
Are there visible holes/gashes in the tire?
Does the wear indicator indicate you should replace?  (Some tires have dimples or grooves that are there to indicate when the tire should be replaced.  Some have an alternate color of rubber underneath, and when that shows through the tire should be replaced)

Smooth tread is actually ideal for road conditions, but not commonly found on tires.  If you're on hard surfaces such as pavement/asphalt, the tread doesn't help you and actually slightly reduces contact area and increases rolling resistance.  On most road tires the minimal tread pattern is just cosmetic to make their customers feel better (since a smooth tire looks slippery).

See also: Sheldon Brown's comments on tire replacement and tread patterns

If you plan to ride through mud, sand or other soft surfaces, you need tread.  So when you no longer have tread on your mountain bike or cyclocross bike's tires, it's time to replace them (unless you plan to only use them on the road).


Removing bike interfaces to reduce likelyhood of theft? Is there a product out there that allows you to remove interfacing components? Like being able to remove your brake lever arm, shifter arms, pedals...etc etc easily and efficiently so it makes the get away process more troublesome for the thief? ... therefore it might deter them from taking your bike?

I'm aware of thieves just being able to pick up bikes, but if you also had two U-locks on a sturdy pole, I would assume that this would be much more troublesome for the average thief.

I guess this would be more troublesome for the user...

You can get quick release pedals (some folding bikes use them) with the advantage that the mount point left behind is too small to effectively pedal on. Pedals are also small and relatively clean if you carry them with you, so this works fairly well.

(MKS Ezy quick release pedal)

Commonly people with concerns like yours will install a quick release seatpost bolt and take the seat with them instead/as well. But seats are large and the seatpost is often greasy or dirty, so I am not a fan of that approach. Re-setting the seat height every time is also annoying.

The other awful thing people often remove for security is their front wheel. It's even bigger and dirtier than the seatpost.

Some not-quite-folding bikes are designed to be taken apart easily. Bike Friday, for example, and anything using S&S couplings. You could conceivably take one of the smaller pieces with you every time.

A more extreme variant is simply to remove parts and leave them off. Many fixie riders claim that people won't steal a fixie because they're hard to ride, for example. Riding a unicycle can be an extension of that idea... people won't steal a "bicycle" that has one wheel, no gears and very few valuable components, and that they can't ride.

There are a few types of bike thieves, and you need to deter them in different ways. The lazy thief who just wants transport can be deterred by almost anything (bike locked with any non-trivial lock); the opportunistic/unorganised thief who will steal anything easy and hope to sell it quickly, for whom you just need a decent lock and use it to attach your bike to something solid; and the professional or organised thief, for whom nothing short of a security guard will do as long as your bike is worth stealing. Both steal-for-sale thieves will also steal components off your bike (as will other cyclists who don't think of themselves as criminals). Normally only the easily removed parts like wheels or pumps, but I've had brakes and handlebars stolen off my bikes in the past.

A general solution is to take everything of value off the bike and replace it with cheap crap. That's a junker bike and they're very popular for this reason.


What does a cyclocomputer actually measure for calculating the speed of the bike? What does a cyclocomputer actually measure for calculating the speed of the bike?
Is it the time for one revolution $T$ or is it the number of revolutions $n$ per given time $t_0$?

If the radius of the wheel is $R$ then you get the speed of the bike $v$ by

$v = 2 \pi R /T$

in the first case and by

$v = 2\pi R n/t_0$ in the second.

It might seem to be a tiny difference, but I am really interested in this detail. Hope someone could clarify this and give some references.

The answer is "both, depending." The majority of current bicycle cyclometers use a reed switch and timer, and measure the time between successive triggerings of the switch as a magnet passes by. An advantage of this method is its simplicity and low cost, though if the magnet is ill-positioned or if the rotational speed of the wheel is too high, the reed switch can get fooled since it takes a while for the reed switch to reset itself.

A less common approach (used by the old Avocet line of speedometers, including the venerable and venerated Avocet 50) used an induction coil and magnet ring with 20 small magnets attached around the hub. The induction coil could rapidly count the change in current. You can see the details of this approach in the Avocet patent application for the 50, but its designer discussed some of the idiosyncrasies of that approach in this Usenet post from 1994.

Although these two different methods can be used to collect the data needed to calculate speed, the exact algorithms used may differ from device to device. One can see this in the way that cadence is often calculated. Almost all bike computers that have a cadence sensor use a reed switch, since the rotational speed of the cranks is low enough for reed switches to reset. However, different manufacturers use different averaging periods, time-outs, delays, and triggering events before displaying the result. Speed calculations work similarly, and one can occasionally see the evidence of these choices by examining speed and cadence data from bicycle computers that store these values and allow them to be downloaded after the ride. Here, for example, is a graphic that shows the speed recording from three different devices that were mounted on the same bicycle for the same ride (a PowerTap, a Polar S710, and a SRM Pro -- these are power meters but here we focus only on the recorded speed). Each device was set with the same wheel circumference but the histograms show that each stores and reports slightly different speeds.


Riding a bike on a tilted road I have a dutch city bike (similar to the one shown below) with broad tires that I use for commuting short distances. When traveling on roads with a slight tilt (left to right, perpendicular to the road), I often find myself feeling unbalanced, as if tilt of the road is exerting a force on my tires, pushing me against the tilt.

What am I doing wrong? Can something be wrong with the bike/tires or is it just "me"?

If you feel no "tilt" on a flat road then there is probably nothing wrong.  A bike's steering geometry is designed as a compromise, using terms such as "rake", "head angle", and "trail".  A bike designed for agility will generally have a geometry that makes it turn downhill on a slope (if you let go of the handlebar), but a bike designed for stability (such as yours) will tend to turn uphill.  This tendency is amplified by the wider, lower pressure tires.

I doubt that there is anything wrong with the bike, unless this effect is very pronounced.

If you find the effect unsettling you might be able to reduce it by increasing your front tire pressure 20-30%.


Basic MTB suspension adjustment I've been given a Trek 4300 mountain bike by my dad. I usually ride a road bike. After my first ride I'm sure I need to reduce the springiness in my from forks. There are two dials there labeled RST preload. They are tight, but I can turn them. I tried 360 and 720 clockwise and anticlockwise, but couldn't tell which way was correct. I see that other bikes allow air in here, so maybe I need to flip these off. Can anyone advise?

The 4300 came with a very basic suspension. As such it has very basic adjustments. The preload adjustment makes the spring feel stiffer by slowing the initial compression of the fork. There is no dampening or rebound adjustment which would control the speed at which the fork extends after it compresses. What you may be experiencing is the lack of rebound control. The preload is at its' max with the knob screwed in or turned counterclockwise until it stops. It is possible that either the knobs are broken or the fork has worn out if you see no difference with different settings. Unfortunately there are no parts available for these. Your bike has a 1 1/8" straight steerer tube which is no longer used on higher quality forks. So your options are limited to looking for a older used fork or replacement with a size adjusted rigid fork.


How does fork offset affect bike handling? Some forks come in a variety of different fork offsets for the same model.
How does replacing the fork designed for the bike with:

A fork with smaller offset, everything else the same
A fork with bigger offset, everything else the same

Affect the handling of the bike, specifically for downhill and enduro mountain biking.

Offset primarily affects your mechanical trail - that is, the distance between the imaginary straight line going through your head tube down to the ground, and your tire’s contact patch. Normally, the contact patch is behind the steering axis, hence the nomenclature “trail”.

Image from Wikipedia
Increasing the fork offset will bring the contact patch forwards, so trail is reduced.
Decreasing the fork offset will bring the contact patch rearwards, so trail is increased.
Trail affects the steering, as it is basically a measurement of the amount of influence your steering inputs actually have on the contact patch.
Also related are the effects of wheel flop generated by your head tube angle and fork. Since your HTA is (hopefully) not vertical (90°), your wheel will pivot side-to-side when you turn the bars, which adds stability. Among other reasons, this is why head tube angles get slacker as MTBs get more aggressive. Furthermore, fork offset is measured perpendicular to the steering axis. Since your steering axis is angled because of the head tube angle, the fork's offset actually has both a vertical and horizontal component referenced against the ground. The vertical component exaggerates the influence of wheel flop on the steering.


8 speed shifter with 7 speed cassette I just got a bike with broken hanger and derailleur. As the owner didn't want to put money in good parts, I installed a cheap Sunrun derailleur compatible with index, and a new hanger. Just after I finished the work, adjusting the cable I noticed, that it have 8 speed shifter and 7 speed cassette. I know, that it's not an issue, and there is no problem to adjust it normally and I left the 8 as ghost, but this time I couldn't adjust it: if all the gears shifting up good in 7 > 1 direction, they will not shift good down (1 > 7) and vise versa. There is a point that both directions not shifting well, like remain at gear 7 while shifter showing 6 and remain at 1 while shifter showing 2.
Am I missing something? I cleaned and oiled the shifter, cleaned outers, put a new cable and new derailleur.

Assuming the shifter and derailleur have compatible cable pulls (which you should check), you won't be able to perfectly adjust the shifter to shift smoothly on a cassette of 7, since the cable pull which moves the shifter for 8 speeds is likely not enough for 7 speeds. Thus, generally, you need to match the shifters with the derailleur and the cassette spacing.

Sheldon Brown has some comments on 7 speed setups and running an 8 speed shifter with 7 speeds through some alternate cable routing, but given that you can buy an 8 speed cassette for like 10 bucks, it seems like an unnecessary hassle (given the extra time you'll be spending tweaking adjustment). Or you can bolt on a 5 buck friction shifter and save yourself some time too.


Breaking spokes on adult tricycle My mother is 60+ years old and 200+ lbs.  She never learned to ride a bicycle, so she rides a Schwinn Town & Country adult tricycle.  She loves it and rides it everyday, 2-5 miles everyday.  The spokes on the rear right wheel keep breaking.  In the past year, since she's had the trike, she must have had 5-10 spokes replaced. The right wheel is also the "Drive" wheel, and the only wheel giving her problems.  Could it be a shoddy wheel? a bad wheel builder?

What could be done to fix this?  Stronger spokes? Replace the whole wheel for a new one?

I need help and I'm officially out of ideas...

Here is my 2c from over 10 years experience in a busy shop:

I am assuming that it is the spokes are breaking at the hub.
On a drive side wheel, that is where they always break.

There is a different rare condition, when the spoke nipples are breaking off at the rim.
Rims have two sets of holes, one set on the each side.
The spokes might be laced to the opposite side of the rim.
I have never seen this from any bike factory, but rather from amateur wheel builders.

When a wheel starts breaking spokes, the spokes are almost always to blame.
Aged galvanized spokes that are gray or rusty can have all kinds of microscopic corrosion fractures at the bend.  If the spokes are not corroded, or were made of stainless steel, it could even just be a bad batch of spokes.

Even if a bad wheel build was the original cause, the remaining spokes are damaged and will break with continued use.  Re-tensioning the old damaged spokes won't help.

I am surprised the bike shop replaced the spokes one at a time after the second time it came back.  If the wheel is breaking spokes, it will continue breaking spokes until the entire set of spokes is replaced.

There is one other possibility with three wheelers.
I have not seen a Schwinn three wheeler up close for 15 years or so, but in the old days they had chromed steel hubs, and those can sometimes be a problem.

If the steel hub has a sharp edge in the spoke hole, that is a stress riser.
The spokes break right where the spoke bend hits the sharp corner.  Aluminum hubs are softer and will deform a bit - no sharp edge, no stress riser, no breakage.

The drive wheel on a three wheeler uses a special hub, special made for that exact trike, so you are pretty much stuck with the hub it came with.

I have lightly chamfered the spoke holes in some problem steel hubs with a countersink bit to remove that sharp edge.  A dab of paint to avoid rust is useful too.

While the chamfering makes logical sense, and those wheels never came back, it is hard to tell if the chamfering did the trick, or if a set of new high quality stainless spokes was enough to cure the problem.

If the trike is only a year old, it should be a warranty repair to get a proper fix, not just one spoke at a time.  Either replace all the spokes with quality stainless spokes, or replace the wheel.  I would trust a new set of spokes more than a replacement wheel.  If the shop won't handle this under warranty for a one year old trike, then contact the shop owner, or go up to Schwinn corporate if you need to.

Hope this helps.


Is there a good way to clean brake hoods? I just picked up an old bike with white brake hoods. They are pretty gnarsty, covered in a greyish brown layer of filth.

I've tried a soapy rag and scrubber brush with elbow grease. It takes care of most of the issue, but they're not pure clean. Is there any trick to this?

I have been using "Foaming Bathroom Cleaner" aka Scrubbing Bubbles and an old toothbruth for about two years with good results. I can't say anything about the long term results as it's only been two years. Your case might be tougher as I think the biggest tip is to clean them before the dirt gets really ground in.


What is the difference in shifting performance between Campy rear derailleurs? During the past few weeks, I've encountered a couple of times the statement that there is no difference in the shifting performance across different tiers of Campagnolo rear derailleurs. I.e., one gets top-notch performance even from their cheapest offering. Supposedly, higher-end derailleurs are more expensive due to the lower weight and materials used.

Is there any truth to this? Is there any other difference between a, say, Veloce and Super Record rear derailleur other than price and weight?

Performance wise the largest difference is that mid- and higher level derailleurs have ball bearings while low end has nylon sleeve bearings. That and better quality materials together make more durable product.

Paying for high end gets you carbon fiber parts which mainly save weight and ceramic ball bearings which are mostly useless in bikes.


Difference between thick vs thin front suspension? I visited a bicycle shop a few days ago. I noticed two different types of bikes. One with thick front suspension and the other with thin front suspension. Bike with the thick suspension was more expensive.
Does thick suspension provide benefits or just add weight?
Is thin suspension more better than thick one?

Thick Suspension:

Thin Suspension:

Full Images:

Fork-leg diameter is not really how you would classify suspension forks. Or more exactly, it is a way, but not really the most relevant.

Suspension forks could be classified by how much travel they provide (different travel for different specific uses), the suspension mechanism (springs, fluid, elastomers, air, hybrid), the damping mechanism, etc.

I suspect that both those bikes were pretty cheap, both probably use spring suspension, and neither is really intended for hard off-road use. A bigger-diameter tube isn't necessarily heavier, as it can be made with thinner walls.


Funky Rear Axle. Need help Identifying I recently bought a Globe Work 2, and I'm digging it, but I'm at a loss for what is going on with my rear axle.  I took a couple of pics (below), so I'm hoping someone can tell me what I've got.

According to the spec sheet, I'm supposed to have "REAR HUBDouble-sealed, loose ball, dual-lock nuts, steel axle, QR, 32h", but that doesn't look like a QR to me, and I don't know what dual-lock nuts are.

So, any ideas about what this is?

Looks like an attaching point for some kind of trailer, maybe a single wheel trailer.


What's the logic behind this chain length estimation method? I know of several methods of sizing a chain for a bike:

As many links as the previous chain.
Small-small. The RD should be barely expanded, the chain nearly rubbing against itself roller-cogs. The logic here is to be able to have the longest possible chain, that still allows shifting into any gear combination.
Vertical rollers. Shift big front small rear. The rollers on the RD should be in a vertical line, below the cogs. In this position the RD is in a good working point, because it's spring is both tensioned (and thus stiff against vibrations) and not over-elongated (and suffering accelerated wear). This is the medium working point.
Big-big without the derailleur. Without threading the chain through the RD, measure big-big and add 2 links.

My question is what is the motivation of the last method. To me, not threading the chain through the RD just doesn't make any sense. What physical quantity is being measured by shifting to big-big and why are 2 links being added?

As a side note, I recently tested all of those, and no two returned the same result.

Big-big and through the dérailleur is the most chain you'll ever need as you can't shift to any gear which takes more chain than this.

You will then need to add some links to take into account the extra chain required to go through the dérailleur.  2 links is the least amount you can add and when the rear mech is as stretched out as it would near maximum extension, the chain doesn't need to be much longer to accommodate this.

Theoretically you could put the chain on big-big and through the dérailleur and try and gauge how long the chain should be for the mech to be almost fully extended but not quite, but by doing big-big plus 2, you should get a similar result.

On your side note that each method gives different results, this could be because there is no correct answer.  The big-big plus two gives you a safe chain length in that if you were to shift into big-big there would be sufficient chain to do this.  If you don't cross-chain, you could get away with a shorter chain length, but risk damaging something if you were to shift into big-big.


What speed is my Shimano Nexus 8 Hub in? I made a mistake when changing a flat. I didn't have it in 4th speed. When I was changing the flat I shifted it for more give on the shifter cable >_< . Now my shifter says 4 and I don't known what the gear is actually in.

I've been field testing it to get the 4 on the shifter to put the hub in 4th speed. I'll commute to work, experience slippage, adjust it so the yellow lines match, and continue experiencing slippage.

I'll unhook the shifter cable. Shift down so 4 is now 3. Field test again.

How do I know what speed my hub is in when the shifter doesn't match?

Put your shifter in 4th gear. Adjust the cable tension so that the yellow lines match. There really isn't more to it. Not much to do wrong. If you can then shift all the way up to 8 and down to 1, the basic installation is correct.

However ... from my experience, these hubs change a little over time. Mine (Alfine 8, basically the same thing) shows slippage in some gear every time I re-install it. After aligning the yellow lines, try to slacken the cable a little bit. This could be closer to the setting the hub was before you changed your tire.


Convert MTB mechanical disk brakes to hydraulic I want to convert my mechanical disk brakes to hydraulic. I don't know what size calipers to get. I plan on using the same rotors.

Worth reading, not a dup - What is the difference between I.S., post, and flat mount disc brake mounting standards? -

The calipers are (mostly) standard mounting, its the mounts that determine the size of the disk used. Therefore you can 'just' (that infamous trivializing adjective) buy a new set of brakes, bolt them on and start riding.

When buying, you can buy prebleed brakes ready to bolt on with hoses attached. This is easy but the hose length is usually a bit too long - however no bleeding is required. Its possible, in theory and if done with care, to shorten the hoses without needing a bleed the brakes afterward.

If you go with pre bleed brakes, be sure to get the correct 'handedness' of the levers. Different countries have the brakes on different side, the front brake will have a shorter hose and rear brake a longer hose.


i need to replace both wheels on a Giant Escape3 which are compatable? I need to replace both wheels on my Giant Escape 3 (2016) which ones (700) are compatable?

Giant may vary the spec in other markets, but I found this listing:

https://www.giant-bicycles.com/en-gb/bikes/model/escape.3/22033/83618/#specifications

The rim width isn't listed, but with 32mm tyres, Sheldon suggests 15-19mm.

The gearing on the stock wheel is a 7-speed screw-on freewheel, but getting a wheel with a freehub and a 7-speed cassette should not cause problems.

Without disc brakes, the dropout width could be 130mm or 135mm; as this hybrid looks to be designed more like a mountainbike than a roadbike, 135mm is more likely.


Storing bicycle helmets...will temperature affect the performance of the helmet? I got into a discussion at home about where to best store our bicycle helmets. We store our bikes in the garage (a standalone, not attached to our apartment). So, logically and aesthetically my wife wants to store it in the garage.
My argument against this is that our garage does not temperature control and we live in LA. I think that it can get pretty hot in there during certain times of the year and it can also get cold during other times (winter nights can go down to ~40 F (4.5C)).

My question is whether these temperatures will affect the foam in the helmet in any way. I.e. will it degrade it's ability to provide protection.

The cold won't hurt it -- foam is used to line refrigerators.  And certainly if the temp is going "all the way down" to 40F (shudder!) that's not even close to a problem -- around here it isn't even "cold" unless the temp is below zero F.  (In general, solid objects are not damaged by cold, though they do often become more brittle while cold and hence more apt to be damaged while in that state.)

High temps could be a problem, but again foam (very similar to the stuff used in helmets) is used to insulate homes, where attic temps may reach 150F or so, and it's used to insulate water heaters that run at 180F.  The problem is that extended high temps over, say, 150F,  won't degrade the rigid foam itself, but they will degrade the glues and the foam rubber liner.


Raleigh Twenty forks too narrow to accept 93mm hub 93mm hubs are standard size for the R20s but on this particular bike there isn't enough clearance between the fork ends to get a wheel in (I'm using an original R20 wheel as a replacement so it's definitely the correct size).

I know that the bike had an "accident" at some point that trashed the front wheel but I don't have any other details about what exactly happened to it, so I'm thinking the front might have been run over by a car or something and that crushed the forks somewhat. They look structurally sound, but would it be a bad idea to cold-set them and draw them apart a bit, or am I possibly missing something in the way I'm trying to replace the wheel? I have no experience with vintage bikes so some guidance would be appreciated.

How bad is it?  If it's only a couple of mm then just manually spread the fork slightly as you install the wheel.

(Also make sure that no unnecessary washers have been added to the axle.)


How to cope with boredom whilst cycle touring? I went on a long cycle tour before and I found myself getting bored whilst I was riding at some points. E.g. on monotonous main roads, and areas with not much scenery or people to stop and talk to, or when I got bored of music I was listening to. Does anyone have any advice about how to cope with boredom and in general improve the experience whilst touring.. I like to meet as many people as possible, because I found before that it was the people that made my journey interesting.

As I may have given away in the comments, I'm not a fan of sensory deprivation when you're as vulnerable as you are when you're on a bike. I don't think there are many scenarios where not being able to hear as good as you possibly can is safe on a bike — but you may not agree and safety really isn't the point of this answer.

My belief is that when you listen to music, you are isolating yourself. Same applies to an audiobook or a podcast. You may as well go the whole hog and watch a movie while cycling on a turbo trainer. The moment you ride with music, the music has become your concentration. You're only going to enjoy the ride as much as you enjoy the music.

Throw the music away and engage with your scenery. Listen to birds, weave potholes, count squirrels... Whatever you do, just enjoy the majesty, the unimaginable effort that went into creating what you're cycling past.

If you can't do that (and can't swap squirrels for the homeless, potholes for bullets — I have no idea what your area is like!) change your route so you're going somewhere that does interest you. Otherwise, as I said before, you might as well be on a trainer doing something that does entertain you.


How to avoid running over animals whilst cycling on a canal at night? I commute on a towpath in Hertfordshire, England and there is ample amount of wildlife about.

During the day it's fine, I can see ducks, squirrels and rabbits in time and slow down if I need to.

However at night it seems to be a problem as I occasionally have close calls with particularly what I believe are squirrels and rabbits trying to cross the towpath as I'm approaching.

I believe they see me rather too late sometimes and despite my front lights and intermittent signalling with the bell I've not been able to mitigate that. It goes without saying that I see them especially late. Particularly problematic are blind sports just before a turn. It doesn't help that often there are no other light sources apart from my lights.

Has anyone run into a similar problem and has any tips?

My commute brings me through a park with a lot of rabbits (or similar animals, not a zoologist here) and it has been rather close a few times ...

I use a head lamp when driving there at night for two reasons:

It allows me to see through turns much better
The eyes of animals reflect directly back at you, which helps to see them a little earlier

All that does not help when they jump out of the shrubs directly in front of you. It doesn't happen a lot, but I have seen dead rabbits on the path a few times. (No dead cyclists yet)


Attaching crank arm with Shimano SLX M660 Firstly, apologies if this question has tones of frustration, my new crank set and bottom bracket has never been installed correctly, so I am going to do it myself.

Should the drive spline on the left crank be greased? It was assembled with grease but that seems to have helped it fall off twice now.
Can I get an aluminium substitute for the plastic tension nut and if so can someone identify the exact part number I need? I can see they exist, just not certain which one will be compatible.

Background: Originally the shop forgot to put in the bottom bracket spacers, so while the crank and shaft moved laterally making shifting a mess, I think it also allowed the crank to move and take tension off the tension nut allowing it to spin off and disappear. This allowed the crank to eventually just slide off the spline. When it was reattached with a new nut and (this time too many) spacers, it didn't have enough thread engagement and eventually sheared threads, allowing the pedal to slide off again. I never want this to happen again. I intend to get the tools to disassemble the bottom bracket, place all of the spacers correctly, then use an up-rated tension nut whose threads won't shear.

Shimano crank set technical document

Edit: Update
Back in 2012 I rebuilt this crank with grease and by the book. It used the replacement plastic retaining nut, blue loctite on the pinch bolts with correct torque and the correct spacer arrangement in the bottom bracket. This crank has held up perfectly and continues to, three years later. The titanium nut arrived but has never been needed.

The cap is like the star-fangled nut on a threadless headset - it's only there to hold the crank in place when you do up the pinch bolts.
If the pinch bolts aren't holding the crank in place on their own, something else is wrong, and you really need to fix that. If the crank splines are worn because the shop fitted it wrong in the first place, they should replace the crank.


Should I consider replacing bottom bracket? I have a Cube Acid MTB from 2002. It has been used for 45000km, but only during summer on the road, and never in the rain, so absolutely no water on any parts.

Since I will be replacing other parts during the winter break by myself, I was planning on having the LBS to remove the BB so I could find a similar one, and then have them install it before next season.

But I am not sure it is needed. I was just thinking that 45000km sounded like a lot for a BB that has not been serviced for 16 years. The rides the last few months has felt a little bit "muddy", like when you walk in water there is some resistance, but that could be the chain which is a little bit dirty and old (Shimano HG93 XT 27000km).

I have just removed the chain, and when I pull the pedals I do not see any play and when I spin them, I do hear a little bit of noise, but it is more "whoosh" than any creaking or grinding noise, and it does seem to run smoothly.

I do not know exactly what BB is installed but it have to be some standard Shimano. So should I consider replacing it after 45000km in dry conditions or is it possible it can be used for many more miles?

Does anybody have a guess about what BB is installed? I can measure the axle length and diameter, but all this with square tapers and thread, I do not know anything about.

I would have though that after  18 years and 45000km the bottom bracket would be worn out. I recently learned that bearing wear is heavily dependent on load (source: GCN Everything You Need to Know About Bearings) so if you are a light rider and are not putting out lots of power I guess the bottom bracket bearings could last that long.

If you are not feeling any play in the bottom bracket bearings and they turn smoothly that's further evidence the bearings are OK. If you can you should pull the cranks off and turn the axle with your fingers. You may find you feel drag or 'notchiness' that the mass of the cranks is disguising.

You very likely have a cartridge type bottom bracket bearing unit, these are not particularly expensive and are available from a number of vendors so you may as well replace it. I'd check the chain with a wear gauge and consider replacing it, and look at the chainrings and sprockets as well.


Is this tire properly fitted on the rim? My tires are 622 x 38C, and on the rim it says 622 x 21C (m̶i̶n̶i̶m̶u̶m̶ ̶t̶i̶r̶e̶ ̶w̶i̶d̶t̶h̶ ̶t̶h̶e̶ ̶r̶i̶m̶ ̶s̶u̶p̶p̶o̶r̶t̶s̶,̶ ̶I̶ ̶b̶e̶l̶i̶e̶v̶e the rim width).
These tires cost around 18 dollars each.

I've spent some time on:

making sure I haven't pinched the tube and there is no foreign object between the tire and the rim;
deflating, adjusting the bead, trying to straighten the tire, reinflating;

The rim is true, the bead seems fine, yet the tire has a noticeable wobble (~2mm I would say):

This is how the bead looks:

These are the original components of a 170USD bicycle I bought from Decathlon a month ago. They have bicycle mechanics and a repair shop; but I guess they don't spend a lot of time fine tuning the bicycles before selling, especially the cheaper ones.

The front tire (which I haven't touched yet) wobbles a bit more; the rim is also 1-2mm out of true.

Will this tire wobble wear down the bearings faster, or other components?
Or is this amount considered normal, and won't do any harm?
Is this as true as you can get on such a cheap bicycle?
Should I spend more time trying to adjust or leave it as it is?

I'll answer all your questions in order.

1) "Will this tire wobble wear down the bearings faster, or other components?"
   -Nope, this wobble will do pretty much nothing to the rim. If anything, you will feel the slightest of 'floating' (the only way I can describe it, the bulge ever-so-slightly lifting the bike when you go over it.)

2) "is this amount considered normal, and won't do any harm?"
   -Any tyre wobble is not classed as normal, though it will not do any harm to you, the bicycle or your bike's performance.

3) "Is this as true as you can get on such a cheap bicycle?"
 - The bicycle has nothing to do with the tyre. If the bike was £120, you can still get £80 Continentals. The tyre's quality, however, is quite a big factor. If you bought them for £12 a piece, there's a high chance that there may be minor defects.

4) "Should I spend more time trying to adjust or leave it as it is?"
   -Leave it. If anything, you risk doing more damage to the tyre/rim, constantly playing with it.

Ride around on this tyre for a couple days. In my experience with cheaper tyres, they'll settle down. It's usually due to storage/transit. Re-inflating usually gets rid of any deformation, though not always. Riding it for a while will eventually get it to even out.

If the tyre is damaged, you'll usually notice a very major bulge. If you take an innertube and inflate it, looking at the valve, you'll notice it has a weird shape around where the valve is. It'll look somewhat like that, but on the tyre.


Front wheel oscillation I'm not sure if oscillation is the right way to describe this, but when I'm riding at speed (say around 35-40 km/h) and take one hand off of the bars, the bars shimmy or oscillate – kind of like they are resonating with something. It's not bad, but it's new – I'm pretty sure the bike didn't used to do this…

Does anybody know what would cause this? Or better yet, what can be done to eliminate it?

In case it matters the bike is a Trek 620. The front wheel is a pretty plain vanilla rim with Schwalbe Marathon tire (32-622) and a Sanyo dynamo hub.

It seems like it could be:

Loose Hub
Loose Headset
Untrue Wheel
Tire messed up one way or another

From your description, it's hard to believe that the source is in the rear half of the bike (I'm assuming it also happens when you're not pedaling, correct me if I'm wrong).

It seems to be a fairly minor problem (for now at least), that could be very hard to pinpoint.

If you can't find the problem after a technical inspection, I would just keep riding. If you notice the problem getting worse, inspect it again (it'll be easier to find).


Campagnolo master link won't fit I bought a Campagnolo master link (this one) for use with my Campy 10 speed chain. When it's not on a chain, it joins up and clicks into place and all is well.

However, when I try to fit it around the chain link the pin doesn't seem to go through far enough to allow the groove in the pin to 'engage' with the opposite groove. Based on the packet it seems there are different pin lengths.

How do I know what pin length I should aim to get to fit my chain? Are there different 'standard' lengths for Campy chains?

Campagnolo have 2 types of 10 speed chain, 6.2mm and 5.88mm (Ultra Narrow).

If you have the older C10 chain you will need a 6.2mm master link.

Measure the chain to confirm the width but this is likely the issue.


I need help finding a quality replacement axle I have a Diamondback Outlook Omni 181 CL, bought it second hand for $40, and I'm not sure of the original parts. Recently I have been having trouble with the rear axle, the one it came with bent so I replaced it, and then next two bent. I don't do anything extreme, I ride ~6 miles a day, mostly on sidewalks. I'm tired of replacing the axle, I'm tempted to switch to a solid axle, as I currently have a hollow one for a quick release but I don't use that feature often. I don't know if the axles I have gotten are just bad or if there is some damage to the wheel that is causing the axle to bend, but I don't see any damage to the wheel.

One of the axles I have tried:

Broken axles are an inherent feature of the 'freewheel' hub design. They happen because the load from wheel bearings is close to center, where it has more leverage than closer to axle ends. Newer 'freehub' cassette designs solve the problem with either having bearings inside the cassette close to axle end or with oversized axle.

The best option would be replacing the rear hub with a freehub type. The easiest way of doing this is replacing the entire rear wheel. If this is not an option, an original axle from known brand should be expected to last longer than random junk from Amazon or Aliexpress or at least have a warranty. A solid axle does not help, because the reason for breaking is tension from bending the axle. The tension is greatest at the surface of the axle, so solid interior does not help but the compression from quick release skewer slightly reduces it.


Should I buy a cyclocross bike or road bike to do Triathlons and CX? I have a mountain bike and used it in my first triathlon without slick on. Now I'd like to get into doing triathlons just for fun, not competitively. I'd also like to get into doing cyclocross. Here's my dilemma...should I purchase a road bike and just use my Gary Fisher mountain bike for cyclocross or should I buy a cyclocross bike and use it for Triathlons? Any suggestions? Also what are the top brands for both road bikes and cyclocross bikes for a 5' female and cost range around 1K?

If you have the budget for only one more bicycle you cannot go wrong with a cyclocross bike, you will be able to race CX in the fall (typically after triathlon season) and you can get some fenders and slick tires for road rides in winter/spring and take the fenders off when the weather turns nice for Triathlon season. You can get clip on aero bars if you really want to, but since your planning the triathlons as fun events, there is no need for aero bars or a tri specific bike.

I use my CX bike year round, either with CX tires during cross season or fenders/slicks during rainy season and take the fenders off during the summer months.

You can get by with a MTB for cross races (I see people all the time with MTBs at cross races), but it will be heavier and harder to carry up the run ups and over the barriers.

Take a look at Kona - 'Jake' or 'Jake the Snake' for a good CX bike.

Keep that mountain bike and try an XTerra (offroad) triathlon, lots of fun!


Are modern forks compatible with older style bikes? I have an old 10-speed bike (likely 80's vintage) with a threaded fork. Can I replace it with a modern threadless fork with the style of stem that slides over the top of the fork and clamps on? I know I'd need to replace the stem and handlebars too and am happy to do that.

What do I need to look for? Is the diameter of the head tube different with newer bikes?

The technical term is "threaded fork". That is, the steering tube has threads on top for the headset to screw onto. The newer design is called "threadless" - that's the one where the stem clamps onto the steering tube with pinch bolts.

You can switch from one to the other as long as the diameter of the steering tube is the same. (You'll obviously have to use a headset and stem designed for the type of fork you have.) The problem is, the diameter is often not the same. Around the same time as the threadless forks were introduced, they started making the steering tubes and head tubes thicker. The old ones were typically 1 inch (that's the steering tube outer diameter). The new ones are 1.125", sometimes 1.5".

You should measure just to be sure, but I bet you have a 1". It's possible to get a 1" threadless fork, stem and headset, but the choices will be pretty limited.


Ultegra 6800 chainrings and Claris r2000 Does claris R2000 crank arms can fit ultegra 6800 chainrings?

Claris - https://bike.shimano.com/en-US/product/component/claris-r2000/FC-R2000.html
Ultegra - https://bike.shimano.com/en-US/product/component/ultegra-6800/FC-6800.html
They have the same PCD and chain line which are the two measurements that show you whether the chainrings will sit correctly. I would be surprised if they weren't compatible based on this but I'm not 100% sure they are so take this with a grain of salt. Their Q-factors are different but I doubt most people would notice 3.4mm difference.


which suspension seatpost for a granny who wants a comfortable ride while cruising the neighborhood It is so hard to find info for the granny who just wants some general info for a comfortable ride.  I don't need a professional mountainbike seatpost and not worried about if it is carbon or not, don't understand the difference between long or short travel, not concerned about weight of the seatpost or competion.

But I am a tall granny with a hard tail commuter/crusier ebike and the bumps hurt my back.  I don't want to spend several hundred dollars if 50.00 will do.

Does anyone have suggestions.  I weigh about 155 and tall.
Nancy

I'm afraid questions seeking product advice are off topic here:

https://bicycles.stackexchange.com/help/on-topic

Questions seeking product, service, or learning material recommendations are off-topic because they tend to become obsolete quickly. Instead, describe your situation and the specific problem you're trying to solve.

However, my advice would be to investigate the possibility of running larger, higher quality tyres at a lower pressure before experimenting with suspension seatposts.

Larger tyres, with more supple casings, run at lower pressure conform to the surface much better and greatly reduce the impact of road imperfections.


Why do you think I nearly fell on this turn? I was riding my new Scott road bike yesterday and I nearly took a terrible fall.  The pavement was wet and there was a curve.  I was riding approximately 15 mph and I braked with the rear brake.  As I applied the brake the rear tire nearly spun out from under the bike.  Do you know what I did wrong?

You braked too hard given the road conditions, plain and simple.

The road was wet, which decreases your traction. You hit the brake, which uses the tire's traction on the road to slow the bike. If pressed too hard, the rear wheel will lock up and skid, which can be disastrous in a corner — the rear wheel will continue to follow its outward momentum. 15mph may not seem fast, but that particular corner may have been especially dangerous for any number of reasons:

wet leaves are notorious for being slippery
automotive oil collects on the road if it hasn't rained in awhile, or if there's poor drainage
there was a dip in the road
the road may have been off-camber (the road slopes down toward the outside of the turn)

To avoid accidents in the future, the first thing you should do is properly learn to use your front brake. The front wheel will not skid under reasonable cycling conditions. Other than that, you'll over time develop a sixth sense of how safe the road conditions are. Just pay attention to the corners and watch out for dips, debris, puddles, and the camber of the turn.


Troubleshooting a new shifter I'm trying to troubleshoot a new rear shifter that my bike store installed. The new shifter is a Shimano EF65, 9 speed. The bike is a 2016 Trek Allant 7.4D. I don't know what the derailleur is off hand and the bike is back at the shop at the moment, it's definitely a shimano 9 speed.

The 1st time I picked the bike up after having the new shifter installed there were about 3 bands across the entire range where shifting up OR down did nothing in terms of which cog the chain was on, they were more or less dead spots.

The 2nd time I picked it up after having it adjusted I had to shift down 2x then up once to get it to go down one gear: shifting down one time did basically nothing. Sometimes I thought it'd be in gear and then there'd be a massive *crunch* while on full power as it slipped down into the gear I'd actually selected. This nearly threw me once or twice.

The 3rd time I picked it up the downshifting problems were limited more to the upper gears (i think). 7 -> 6 would take about 200m of pedalling before the chain would eventually clunk over so I still have to downshift twice then up once to make sure I'm properly in gear.

Before I dropped it off it was shifting fine except for the 10 minutes before the original shifter failed. For a moment it randomly wouldn't shift down every now & then, then it wouldn't shift down at all - there was 100% play, like the down shift lever was just gliding with no resistance. I tried to limp it to the store but about 10 minutes after getting stuck in top gear the bottom of the shifter fell off onto the road and the inner workings spilled everywhere.
Apart from that... it was running like a Swiss watch. It's been given a thorough service less than 3 months ago.

I think everyone's a bit confused at the moment. Are all shimano shifters for the same speed compatible? Is there a chance my derailleur could have worn along with the shifter so they'd be compatible with each other but not with a new drop-in replacement? What else could really have gone wrong? The hub's been inspected to see if the gears are indexing properly and apparently that's not the problem. I'm scratching my head a bit at the moment trying to figure out what could be wrong. We've spent about a month working on it so far and we haven't had much success getting it back to the way it was working before the original shifter failed.

Update as of 15th May:

The mechanic tried a spare derailleur. He installed new Alivio cassette. He replaced the inner core of the shifter cable with a SRAM core, as he mentioned it looked as though the old core was snagging. He replaced the shifters with another set of Alivios.

Every single time I've picked the bike up from the shop the guys have told me it's been tested and is running fine. I don't doubt that they're telling the truth. I had one good ride to the shops taking about 45 minutes with panniers on and didn't experience the problem that one time. I usually ride for 1 to 1.5 hrs and every other ride, apart from that one good trip, I have experienced the problems a few times during the ride. This may be completely coincidental but I think I noticed the problems more frequently in the cold.

I'm wondering if the crunch / free spinning / lack of resistance on the crank sensation could be the freewheel, and the slow shift times might be a separate problem? The crunching seems to be set off most often when I shift from 7-8 but it also happens on bumps & spontaneously a bit.

Last time I rode the bike I had time to start my helmet camera once the gear had already stuck, and recorded and additional 30 seconds of me shifting up & down without the derailleur engaging the lower gear.

              Hopefully you can see from the video which gear is stuck at the time, or any other detail that might be relevant.

Thanks in advance for your help!

I would start by looking at the shift cable and housing. The housing may be flexing too much and the cable may be sticking in the housing. This causes cable movement at the shifter to not be reproduced at the derailleur. If you are replacing the shifter it's a good idea to replace the cable and housing at the same time.

Assuming you have a 2016 Allant 7.4. That bike came with 9 speed Acera shifters and a Deore rear derailleur. The EF65 shifter is a Tourney level component - that's at the bottom of the Shimano hierarchy. That may also be contributing to the problem. I definitely recommend going with a better shifter that matches the rest of the drivetrain.

If your bike repair shop has spent a month trying to get this right with no success I'd also consider trying a different shop.