What are common causes of premature chainring wear? My bike mechanic told me today that my front chainrings are starting to wear out and I should consider replacing it soon (with my next chain replacement). The cassette is still in good condition and does not show any signs of needing replacement. The bike has 3000 to 4000 miles on it and all parts except the chain are original.

The specific reason for the visit to the mechanic was due to the chain dropping to the inside. The drivetrain is all SRAM Rival. There have been no other issues with the drive train. The mechanic seemed to think it was a bit unusual for the front chainring to wear out before the cassette, though it was not unheard of.

Are there any common causes (ex: lack of specific maintenance?) that would cause the chainring to wear out so much faster than the cassette?

Why do you wear chainrings quickly?
Cross Chaining - If you tend to be in the big ring on the back and the big ring on the front at the same time, you're probably doing it wrong. Same with running the small ring on the front with the small ring on the back.  This can cause uneven wear on the front chainrings due to the awkward angles the chain must bend. This can wear the sides of the front chainring teeth and make them more pointy.
You are riding dirty or don't lube up first- If you ride offroad especially, your chain can get dirty. If your chain is not lubed properly, it can cause extra friction. Keep the chain clean or it will work like sandpaper, wearing down your chainrings and make sure you use the proper type of lube for your environment. Chain wear tends to deform the inside surface of the gap between teeth, making an uneven 'U' shape between teeth.
Riding with an already "stretched" chain - If your chain is worn, It has a different shape, which is going to cause extra wear on your chainrings. If it's worn too much, you can only really replace it.  Running with a "stretched" chain is probably worse than running with a worn chainring.

If it's a pretty new bike and the chain is well maintained, I'd probably blame it on cross chaining. Be aware of your riding style and make sure you're not overextending the range of your front chainrings.


What is it called when you ride a bmx like a unicycle? I was looking around a bit on YouTube and found a video for a footjam decade... which is pretty cool, in my opinion. However, in this video at 2:44 he rides the bike like a unicycle, straddling the head tube with feet on the pedals... which is freaking cool. What would that even be called?

According to this site on artisitic cycling they refer to a trick called a "head-tube wheelie" which is probably a good name for it. BMX enthusiasts may have a different name for it, but that's essentially what it is.   I was also able to find this other site referring to headtube wheelies.  Also, this Youtube video refers to it as a headtube seated wheelie, and headtube backwheel riding.

After some Googling with the help of @dotjoe's answer, I've found that this trick is referred to a "Pedalling Death Truck" or a "Blender".  There's also a trick called the "forwards spinning deathtruck" which is pretty much the same thing except the rider faces the other way around (at least as I understand it).


Should I replace my bicycle tires if they have not been inflated in multiple years A little over 5 years ago I bought a Magna bicycle. Within the first summer of riding it the rear brake fell apart. I finally got around to having he brake fixed this past month but I am worried about the quality of the tires as the bike (which has been hanging in my un-insulated garage for 5 years with many cold winters) has not had the tires inflated in 5 years. I recently checked the PSI on the tires with my gauge and it is 2 PSI. I'm wondering if I should get the tires replaced. I haven't tried putting any air into them as I don't want the tires to pop. Any help is appreciated.

If the bike has been hanging rather than sitting with weight on the tyres (and hence damaging the sidewalls), there is a good chance the tyres are still ok.

You can check the tyres by going around and looking for hairline cracks in the rubber and feeling if the rubber is brittle/flaky.

If they look ok then go ahead and inflate them and recheck the following day.  If they still show no obvious signs of damage then I would go ahead and ride them.


Why does cable routing utilize alternation of sections of shielded and unshielded cable? Why do manufacturers do this? What's even more interesting, many a bike have the middle cable fully housed, while the other two are "interrupted" as shown above.

IMHO those are the pros and cons of interrupting cable housing:

Advantages:

lighter

Disadvantages:

more complicated to cut to length and install
more friction as there are a lot of enter/exit points for the cable into the housing
far more susceptible to dirt and water
more expensive, because of end caps and labor cost.

As is evident, in my opinion, all cables should have uninterrupted housing. However, all kinds of bikes in all price ranges have these intermissions - on the top tube, bottom tube, seatstay (for the RD). And it is not a factor of weight, as 10-year old massive steel frames also utilize it.

There must be an explanation. But what is it?

It's not a given that the full-length housing is lower friction.  I suspect that a well-done exposed cable scheme is lower friction than a full housing.
Especially for indexed shifters, the cable housing changes effective length with tension and temperature changes.  The exposed cable scheme has much less flex and hence more precision shifting.
The full-length housing is ugly!

I haven't looked at new bikes much in about 5 years, but prior to that the full-length housing was almost exclusively seen on inexpensive bikes, while the exposed cable was common on the more expensive ones.  This strongly suggests that cost is not a reason for exposed cables.  (And reason also suggests this -- the housing is cheaper than the housing ends, eg.)

Of course, full-length housings are more compatible with suspension bikes, and probably have some advantages on true off-road bikes.  So you'll see full-length housings more and more on bikes in that spectrum.


Bike ride not smooth I've a full suspension mountain bike with a 26 inch knobby on the front wheel, this knobby has got these rectangular knobs poking out. My problem is that I find my bike's ride "not so smooth". I currently inflatate my front tire to 32 PSI and the rear one, with a better tread and sleeker dimension, to a 34 PSI. The knobbies are particularly buzzy and make this very unlikeable buzz, even on low speeds. Plus my bike's rear hub makes the rear wheel and freewheel wobble, plus the wheels doesn't rotate very smoothly, what should I attribute the bumpy and seemingly harsh ride to? Also, what degree of changes should I make to my inflation levels? My knobby front is new, so changing is really not an option and well, the knobby owes itself to my unknowing self a while back. What I'm looking for is a better riding experience and satisfaction. And, how urgent is the rear hub overhaul, really? I mostly ride on nice paved roads with zero dirt trail encounters (a metropolitan, no far-off excursions)

I have similar treads and vibration on my hardtail. Some solutions:

Reduce the pressure, but this will increase rolling resistance, thus reducing efficiency. I don't recommend this one. I would prefer to keep the vibration than to reduce my efficiency.
Just replace the tires to smoother ones. I recommend this one because smoother tires will not only make your ride smoother, but also increase efficiency. You should do this unless you are on a limited budget.


Can I swap a 29er fork inplace of a 27.5 if I maintain close to the same axle to crown length? I am looking for some verification of thought process. I have come across a nearly new lower level Diamonmdback 27.5" hardtail MTB. The issue is the front 100mm fork is broken. Doing some online searching for a replacement fork has OEM budget forks (SuntourXCT) for roughly half of the bikes original cost. I can however purchase a 29er fork(Rockshox xc32) with some deep discounts for less than the Suntour. I realize the longer dropout to crown length of the 29er (19 1/4" vs 17 1/4" for a 27.5) will alter the handling. If I got an 80mm 29er fork, that difference would be cut in half. My thinking is that the 1" difference in length would be similar to the difference of the fork length when set to "soft" dampening  versus "firm" dampening while static.

As the axle is also higher, you need to really consider the Ground to Crown height rather than the axle to ground height. Also as the 29er is a larger diameter wheel, it may not clear the down tube, and may interfere with the feet when the pedals are horizontal.

Combining all this and the fact the geometry will alter the handling somewhat in ways that may or may not be significant depending on the bike and your person riding style it seems to be a fairly big risk. Only you can decide if its worth it.


Protocol for downhill cyclist overtaking a car? Last weekend, I was driving (yes in a car, something I rarely do) down a fairly steep and very curvy mountain road (thus with very poor sight lines/visibility ahead) when I noticed a cyclist in my rearview mirror.  He looked "pro" and in control, but was close enough to me that I was worried that if I braked to slow down for one of these curves, I was going to have cyclist splattered all over the rear of the car.

After longer than either one of us would have liked (two minutes or so), I finally got ahead of him enough to slow down a lot and pull far to the right on a stretch with enough visibility for him to pass me on the left (since he was clearly wanting to go much faster than I was comfortable with on the curves) and I rolled down my window to wave "OK" to him.

As he passed he yelled at me (yelling's understandable in this cases, only have a second) about cars needing to pull aside for cyclists.

I felt terrible if I'd endangered him or caused him to damage his brakes or whatever to slow his speed more than he liked.  And I don't even care what the law says if I could do something better to accommodate fast downhill cyclists better in the future, I'm just trying to figure out what I should have done differently.

I think the cyclist wanted me to pull over as soon as I noticed him.  In retrospect I guess I could have done that safely by putting on my emergency blinkers to indicate to him I'd seen him and was planning to slow down.  In the moment, I was worried about how close he was, how variable my speed was around the tight curves, how narrow the road was, and how scant little I could see ahead of me (i.e. I wasn't going to pull left to let him pass me on my right, since I could kill him if I needed to come back right quickly due to oncoming car.)

Anyone have strong feelings about things I should/shouldn't do?

I'm not worried about my rights - I'm far more often the one on the bicycle - so just help me figure out what I should do better next time to accommodate him if I were in similar situation.

Please accept my apologies on behalf of cyclists. Hollerin' something at a motorist who was trying to figure out how to handle an obviously unclear situation was inappropriate. Thanks for doing your best and not killing any cyclists that day!

In general, I agree with the other answers here that you handled this fine and there isn't some magic you could have worked to make the situation go away. Having frequently cycled one of the curviest and steepest highways in the US, I have often been in the position of your cyclist. I also know from a drivers perspective of the same road that there are not a whole lot of obvious moves.

The primarily impetus for any action should probably be on the cyclist. As a motorist being aware helps a lot; but don't try to do anything fancy. Keep it simple. Watch for what kind of move the cyclist wants to make and adapt, but be consistent yourself. He's trying to guess how your car is going to behave -- if you change patterns on him, all bets are off.

The easiest place for a cyclist to pass is usually the place where cars naturally go the slowest. This means curves. Straights are hard because cars speed up (and try to pass each other). While we do have to follow the rules of the road, passing on a double yellow curve is sometimes the safest thing to do on a bike. Inside curves (left turns for US folks) provide the most visibility and a chance to cut a shorter path than the car. The best thing you can do is stay all the way in your lane and take the curve easy. Let the cyclist make the move. You don't have to be in the shoulder or pulled over or anything, just keep your own company and don't wander all over the road yourself.

It's ok to brake. Cyclists have brakes too and there is no physical reason we are forced go fast or follow close. If you want to be extra nice, when you do brake, touch the brakes lightly at first so your brake lights come on early and gradually add pressure to slow the car. In fact, if a cyclist is following you too closely and you are uncomfortable, tap the brakes a couple times to signal you need room to brake. You don't have to actually brake, but the brake lights are the best signal you can give to indicate you want the cyclist to add some distance.

Turn signals are confusing, but usually a right from you means you are going to pull over and a left means you can see the road is clear to pass. However, these are not set and stone and the cyclist still needs to make a judgement call. Hazard lights are even more confusing: I would save them for indicating true hazards.

To make a long story short, drive normally and safely yourself, and let the cyclist take care of the passing.


Extra screw after removing front wheel (plus enclosed hub brakes) My partners bike, a Pashley Princess Sovereign, had a flat front tyre, and whilst I was out a friend came to have a look. He removed the front wheel (detaching the brake, a fully enclosed brake hub), and afterwards had a spare part left over, an eye bolt, pictured below

Would anyone know where this is likely to come from? If it shouldn't have come from the Pashley then it is possible that it was from another bike and had been there a while.

That is a fender (mudguard) mounting bolt. The hole in the bolt slides over the stay that attaches near the axle, and the threaded part goes through a bracket, normally on the mudguard but sometimes at the axle end.

The reason for that is safety - if the mudguard or stay gets caught in the wheel the stay pulls through that hole in the bolt rather than jamming in the wheel and stopping it. So you have a noise and rubbing rather than being thrown off the bike.


Is there a site which has a good collection of recumbent bikes, still for sale new, to compare? I am ready for a new recumbent bike and I know what I want, I also know that I will not be able to get all features in one bike as they are contradictory.

Searching internet shows me a lot of sites with one or a few bikes each or with bikes for sale but not much detail.
On top of that many of the bikes you see described online have been out of sale for years and are very unlikely to be available second hand.

I am based in the Netherlands but with the market as international as it is these days any site with a good collection will be welcome.
Bikes still new in the shops and/or those which have been new in the shops the last 5 years. Sites that collect all that has ever been on sale are less useful.

As I will have to drop some of my 'want have' requirements, I do not look for any particular selection of recumbent bikes.

PS, I am NOT looking for where to buy the recumbent when I have decided on it, I want to weed out a lot of bikes before trying to get to see them because they will not fit my body length or seat height requirements.
I have at least three dedicated recumbent stores within an hour driving distance and at least one local bike store which will order and maintain 'bents but does not usually store them.

I have been riding a recumbent bike for the last 5 years and a recumbent trike for the 5 years before that.
I have been with one or the other to each of the 10 bike shops I feel are near enough to use for common servicing and non of them was selling or even interested in talking about the option of selling this kind of bikes new in the future.
The one bike shop with some recumbents is far enough away that I consider them with the recumbent specialist I will go to when buying but not for day to day service.
(If not cycling, I will be walking the bike to the shop, no use of a car)

There is not a site available (that I am aware of) that does such a thing.  Bicycle Blue Book might be close, but they don't give you the ability to filter by bicycle type.  Somewhat unrelated, I submitted a suggestion to them that they add that feature to their site.

What's available is often not as important as what's available at your LBS.  I suggest anyone new/getting into cycling pick an LBS and start developing a relationship with them by purchasing a bike/trike/bent from them.  A local shop should be able to help you select a bent that meets your requirements, get it fitted and help you keep it maintained after purchase.


How long does it take to replace bottom bracket bearings? How long does it take to replace bottom bracket bearings? Is there anything that can make the procedure take more or less time? How does the type of mechanism affect repair time?

There are three main categories of bottom bracket, adjustable type, cartridge-style, and external-bearing.

Cartridge-style bottom brackets are not serviceable, the replacement requires replacing the entire bottom bracket assembly. Removing the cranks and installing the new bottom bracket is a pretty straightforward task, and should take less than 20-30 minutes.

Adjustable-type can require a little bit of time to get the tension right, plus they are typically more difficult to remove due to the fidgetiness of lockring spanners and the fact that the fixed-cup is typically seized hard into the frame.  I'd allot ~45 minutes to an hour for that task. Depending on the brand of cranks.

External-bearing splits the difference - some have more steps  than cartridge bottom brackets, some are equally simple.

Note that in all cases, using the correct tools is important.


Is it possible/worth it to replace just shifters and derailleurs on an older MTB? I have an aluminum frame bicycle (mountain bike, 21-speed) that I purchased some time in the late 90s, it's marked "Skykomish Eureka" (though I can't find any evidence that such a brand and model ever existed), and it is currently outfitted with Shimano 300LX components.

I believe that the rear shifter is giving up the ghost, as sometimes the lower (up) handle will go all the way back without "catching" whatever it's supposed to be catching in order to shift the gears.

I toyed with the idea some time ago of replacing the components with something more upscale (back then, it would've been Shimano EX, I guess...), but I never did it. Now, I'm wondering whether it's worth the effort. I put several hundred dollars into this bicycle back then, so I'm confident it's not merely a BSO, but technology has come quite a way since those days.

Beyond the basic components (hopefully just a couple derailleurs and shifters), would it also be possible to replace the existing short-arm cantilever brakes with the newer long-arm type (which I assume would increase braking power)?

The great thing about bikes is that almost anything is possible for the home mechanic. But only you can answer the question of whether it's worth it.

Deraillers almost never "wear out", at most they need new jockey wheels. They can get damaged or bent, often is is the hanger that is bent not the derailluer.

So likely all you need is a new shifter, fortunately 7spd is a lot less complicated than bikes with more speeds. $17 for a new shifter

http://www.jensonusa.com/!q!CCO3MwJWuenvYwhoKCsA!/Shimano-M310-Shift-Lever?utm_source=FRGL&utm_medium=organic&gclid=CPby-unl0sMCFRRgfgodc0YAoQ

Or you could put friction shifters on for a little more cash.

What does get worn out is the rear cogs or cassette. You might need a cassette
and chain. That's about $50 more or less.

You can put new canti's on there without changing the levers, if you go to V-brakes you'll need new levers. Generally getting good performance out of canti's has more to do with how well you set them up rather than the exact model you use.

So for roughly $100-$200 in parts, you can have a functional bike again. However, if you can't do the work yourself, paying someone else to do it is a long ways towards the price of a new bike. This also assumes you already have the tools ( although these repairs don't require much in the way of specialized tools. )

For roughly 3x what you'd spend in parts, you can get a lightly used MTB hardtail that will be a much nicer bike. If however, you enjoy tinkering around with bikes, then you really aren't concerned about the cost of parts.

I've fixed up a fair number of older bikes and if you don't enjoy the process and satisfaction of making something old work again, it's almost never worth the effort.


Converting 3x to 1x Drivetrain I have a new crankset (link) on the way as well as a chain guide/bash combo from OneUp. I am getting a 36T narrow-wide chainring also.

The bike I'm working on has a SRAM 3x9 drivetrain with 11-34 cassette. What else, if anything, do I need to convert it to 1x9 (other than putting the new crankset on and removing the unnecessary front der & shifter)?

Is it correct that Shimano 11sp cassettes fit on 8/9/10sp freehub, so I could in theory change it to a 10sp or 11sp cassette? I'm not planning on doing that ATM but just in case...

General consensus is that a 'clutched' rear derailleur is also a key component to a good/successful 1x setup. These derailleurs provide a tighter 'pull' on the chain and help keep it from hopping off the chainring on rough terrain.

For cassette/freehub compatibility, read the discussion that occurred here:
https://bicycles.stackexchange.com/a/28908/30533 ...

  Shimano/SRAM 11 speed cassettes are wider than 8/9/10 speed ones. So yes, you need a new, wider freehub body, unless your old one was not very old and used a spacer to fit a 10-speed cassette.


Road 10 to 11 speed upgrade, what needs to change? Hope all is well.
Currently I have a Cervelo P2 2013 with an Ultegra 10 speed.
I would like to upgrade the drive train from the current 10 speed to an 11 speed setup (either the 105 or the Ultegra). The main question that I have is how do I know which bottom bracket do I need to get for the 11 speed setup to work correctly? Apparently it has a FSA Gossamer Mega Exo bottom bracket currently.
Is there anything else that I would need to consider besides the below:

cassette
derailleurs (front and back)
chain rings
chain
TT gear levers

The current brakes that are on the bike feel fine so I don't need to change those and I have 11 speed compatible rims (Campag Zonda's).
http://www.bikeroar.com/products/cervelo/p2-ultegra-2013/specs

I've done this conversion last year on my #2 bike from a 2013 Ultegra 10-speed to a 105 11-speed, to be able to use the 11-speed equipped wheels of a newer bike on my two bikes alternatively and avoid cassette swaps to do so.
The swapped parts are: the brifters, both derailleurs and the chain. The cassette of course! There is no need to replace the chainrings, the inner width of 10 and 11-speed chains being the same. It is only the outer width that changes because 11-speed has thinner plates. You could also keep the FD but I've chosen the new 105 FD. It is sleeker and easier to set-up and fine tune.
The quality of 105 from the most recent edition is far above Ultegra from '13, due to trickle down of technology. The most expensive part being the brifters.


Are these Xero Lite XSR-3 Wheels suitable for cross riding / racing? I have a set of Xero Lite XSR-3 Wheels.  I tend to ride dirt, gravel, and some singletrack on my cross bike and sometimes some cross races.  Would I be able to swap this wheelset on to my cross bike to save weight or should I stick with my heavier duty 32 spoke wheels.

http://www.chainreactioncycles.com/Images/Models/Original/23418.jpg

They should be fine. There are a lot of people that ride "road" wheels for cyclocross. Unless you have some dedicated tubular wheels with wider and shallower glue beds to accommodate cross tires, you're probably riding "road" wheels with cross tires on them anyway.

I'm currently using some Mavic ksyriums on my cross bike as training wheels and they work out just dandy. Make sure you check the spoke tension often as all the jostling and off road riding will tend to loosen the spokes and throw your wheel a bit out of true quicker than road riding.


Clicking feeling when I pedal I've been riding my bike for quite some time now, and I've noticed I get a clicking feeling when I'm pedaling. I've tried checking the rear derailleur's shifting, tension screws and the derailleur hanger, and the bike still has the clicking feeling.

I don't hear the clicking sound but I feel it, can someone help me please.

A felt clicking is likely to be a bottom bracket or pedal bearing problem. Chain problems tend to be audible clicking or clattering.

If the click is felt on one side only that points to a pedal bearing problem rather than bottom bracket.

A constant stiffness, roughness or 'notchiness' as the cranks turn would indicate a worn out bottom bracket bearing.

You can check the pedals by simply turning them by hand. If they don't turn smoothly the bearings need greasing, servicing or replacing.

You can also check the bottom bracket in a similar way by turning the crank by hand. Taking the chain off the chainrings makes it easier to feel stiffness or roughness in the bearings. Also check for play (slight looseness) of the crank axle in the bottom bracket bearing.

If you are not familiar with bike repair, it’s best to have a local bike repair shop check it out. Bottom bracket replacement is best done by a repair shop in any case as special tools are needed.


Making a Cannondale BadBoy ride softer I have a Cannondale BadBoy with slick tyres, no suspension etc. On roads the ride is fine, but I do less of that these days and more along tracks (e.g. unmaintained paths, towpaths etc.). On non-metalled surfaces the ride is incredibly hard and I get incredible vibration through the forks and frames.

What are my options for modifying the bike so I can mitigate this. Will suspension forks soften the whole ride or just the vibration through the handlebars. My local bike shop recommended knobbly tires, a suspension-fitted seatpost and/or front suspension forks. Or should I just keep the bike for road use and get something more appropriate ?

Wider tires are the first thing to try. The BadBoys are basically rigid mountain bikes with 622mm wheels and narrow tires, so you could also put on mountain bike sized wheels and very wide tires. With a second set of wheels, it's easy to change between road and off-road riding.

About suspension forks, with current geometry there isn't much room for the suspension to work. You could install a 29" suspension fork, but that would change the bike's geometry.


Bent freewheel axle in less than 200km I am trying to understand if the problem I've got falls into a common problem for freewheel hubs. After googling and reading, I am still not sure if there is only this factor to what has happened.

I've done less than 200km on the "hybrid" bike I've got less than two months ago. I can't say I've abused it. I don't feel like it :) Mostly on asphalt occasionally a unpaved road but nothing dramatic like jumping curbs or riding over tree roots. A few days back we went to have a 30ish km ride and I've started to hear this clicking/clunking noise with vibration and sometimes with that feeling of the rear wheel moving sideways. From the 80-90s, when I was a kid and bikes were built differently, this usually meant you have a mess in the hub's bearings. Rightly so, when I came back home and removed the wheel, I've discovered the axle is bent

This is a Shimano MF-TZ21-CP 7 gears set that appears to be a very cheap one. I wish I knew earlier I have to check this too. I think the hub is equally cheap.

Now, I have no idea if this is a "very bent" or "slightly bent" much less I know of what is the cause of what, bent axle munches on bearings or munched bearings bend the axles?

I am reading a lot of people saying the core problem is the "leverage" a freewheel hub creates on the axle and that a heavier weighted rider should expect it to bend or break sooner. I weight 100kgs (220lbs), is it that much for less than 200km "leisure" rides? I mean, am I supposed to buy a box of axle kits to change every 100km?

Update after visiting the shop at May 8th:

So I went to the seller's shop, and left the bike there. As expected, they "didn't have time" to check the damage and quote the work while I was there. Though they told me right away that I "got into a pothole" which I am sure I didn't. At least not a pothole I would consider any danger for any type of bicycle.

So I've told them I didn't and left. Next day the shop owner calls me and says to come and pick up the bike. I ask her if and how much I'll have to pay to which she answers "come here, we'll explain". My favorite. They claim it is impossible to get into a defective axle, and it is impossible it was bent without being "hit". I keep insisting I've treated it properly and didn't ever jump a curb or got into a pothole. They give up with that look of offended honesty to which I say that I am not going to rob them over it and I am not going broke by paying an hour of work and a 150mm steel rod. She says that she is going to be fine too without me paying. I try to explain that it is not a question of paying, but of the service they offer, and that I need to understand if I have to sell the bike right now to avoid repairing it all the time, or it is just a matter of bad luck.  And she doesn't take it well either, saying that she only sells good bikes and not department store junk and nobody ever came back with this bike and blah. So I take the bike and go home. Seems like going back there with any other problem is not the best option now.

TL;DR: Got the axle replaced "on warranty" with some good Shimano 9mm (as they said). Seller wasn't happy about it and I am not convinced it is not going to happen again.

I don't think 100kg should bend a decent axle. I have 7.000 km since I replaced my axle with a Point $5 one and it's still ok, on a freewheel 7-speed hub like yours. Definitely they should replace it on warranty. If not, you can replace only the axle with a better one.


Do liners or other hats worn inside a helmet compromise safety? Is there any data or official (e.g. standards-based) information on the effects of wearing a liner, bandana, or other hat under a helmet?

Like many riders, I wear "headsweats" in the summer for sun protection, and a wool beanie in the winter to keep warm. Both seem thin enough that they ought not compromise the performance of the helmet in a crash. But is there any data on this, or any official recommendation on what kinds of liners or hats can safely be worn inside a helmet, or how best to wear them?

I've never heard of sweatbands, bandana's, or caps being problematic. Curious about what prompts the question?

The only thing remotely similar that I have heard IS a potential issue is plastic sun-visors attached to helmets. Apparently these things can come loose in a crash and scratch/poke the face.

But linings? No way.

Here's a summary of what is involved in the helmet testing used to certify helmets for CPSC, ANSI or Snell compliance. Any issue related to hair or lining would conceivably be addressed by a "rolloff" test. However, in testing the helmet is merely strapped to a form that represents a head size. The standards have no indication related to what's under the helmet other than the size of the form (to test different size helmets). More complete description of testing here.

If there is any design or safety accommodation for lining under a helmet, it would probably be addressed by the individual manufacturers, but I've never heard such a thing mentioned except that some helmets are better with ponytails.

That said, linings of some form or another have been used widely since helmets have started to be worn. I'd like to know if anybody has heard of any real mishap related to linings under helmets. I suspect there is none.

oh... looking further on the bhsi.org, I see there is an article on hair and helmets.


Snow tires for H Plus Son SL42? I'm riding fixed gear with H Plus Son SL42 rims and Schwalbe Lugano.

I'm thinking about changing my tires to be able to ride in snow/wet roads, but in the H Plus Son site I don't see the maximum size tire that I can fit in the rim.

Given the following diagram, what's the maximum tire that could fit?

I've seen some Schwalbe that look good, but they are 700x30C and 700x33C...

For a complete knowledge base on fitting tires for different rim-sizes, see here: http://sheldonbrown.com/tire-sizing.html
and scroll down to 'Width Considerations'.
30 or 33mm tires will fit your rims but they'll probably need a lot of pressure which might just be counter-productive on snow. On the other hand you should consider another possible issue: 30 or 33mm tires might not fit into the front fork or between the rear stays.
If they do, you might want to buy a second pair of wider wheels and use the wider tires on these. It will keep your 'Summer' wheels nice and shiny.


Trying to identify vintage English bike maker I’m trying to figure out the maker of my great grandmothers bike thanks for any help

I think this answers your question.
Your headbadge is slightly different, probably older.

See also https://en.m.wikipedia.org/wiki/Sunbeam_Cycles
Also http://historywebsite.co.uk/Museum/Transport/bicycles/Sunbeam.htm


SPD vs. SPD-SL: Which unclips most easily? I got my first real road bike a few weeks ago, and am now hearing from my local bike club fellows that I should get some clipless pedals.

A quick Internet search reveals that the main types are SPD and SPD-SL, and that shoes made for one type cannot be used with the other. That's not really a problem, since prices seem to be about the same for the whole pedals + shoes package.

Being new to this, I am concerned about not being able to unclip in time to avoid falling over, and for this reason if there is a definite difference in ease of unclipping, I'm heavily in favor of whichever one is easier.

So in the experience of those of you who have used both types, which is easiest to unclip?

In my experience, Time/Mavic Iclic.

This should, however, not be the reason for decision. Both are easy enough to unclip if you remember to twist your foot instead of just lifting it and neither will unclip if you forget it. Don't believe the people who claim falling is part of learning, just practice leaning against a wall and unclip a couple of hundreds times or until it feels natural.

What you should consider is:

SPD-R and road systems in general are very uncomfortable to walk in. They are compatible with some very nice and lightweight road shoes, work very well with shoe covers and have some roadie credibility
SPD is walkable (but uncomfortable, has loud crunching sound on pavement/rocks and destroys floors), compatible with MTB shoes including waterproof and insulated ones and has credibility among grumpy stackoverflowers. There are some SPD shoes that look like road shoes but are in general heavier and less stiff.


100 mm front hub, 94 mm fork dropouts, options? Simple as that. I thought I could He-Man the fork to fit the hub as it's only 3 mm on either side. Looks like it requires a bit of force and I'm concerned about breaking something in the long-run; either the frame or the hub.

I have a Origin8/Formula front hub and an old steel frame (1970s or so) that seems to be in decent condition.

Which option is best: reduce the hub spacing to 94 mm or widen the fork to 100 mm? And in either case, what's the way to go about it?

The front hub is the top one in the picture below.

EDIT
Turns out my problem wasn't spreading the fork. It was the fact that the axle diameter was too large for the fork dropouts. I filed the trailing edge of the dropouts and tried again to spread the fork to accommodate the hub. It fit without issue. Pictures below.

Sorry to provide ANOTHER answer, but I think this one might be interesting:

Take a rear (135mm) axle;
Insert two nuts, one around each side, untill they are less than 80mm apart. One of them might be inserted just enough to allow a small piece of thread to show up in the tip;
Fit the axle into the fork dropouts with the bike upside down, so that both nuts are beween the dropouts;
Start to "unscrew" one of the nuts, thus forcing the fork legs to get away from each other;
Unscrew it after a while and check the distance. It might take some time to figure out how much elastic deformation (preload distance) you'll have to overcome before actually making the new distance permanent.

This method is much more controlled than the lever one detailed previously, but it most probably will take much more time (although I think a rear axle and some nuts are easier to prepare than a large improvised lever system).

Hope this helps


Why am I getting no power when I pedal? Yesterday when I was biking my mountain bike on level paved path, I would pedal but get no power to the wheel.  To use a car analogy, it was as if I had the clutch in and was apply gas.  It seemed to happen most often after I coasted and then went back to pedalling.  I would pedal and realize that no power was going to the wheel.  The chain was definitely on the sprockets and moving. I could change gears no problem while I had no power.  Sometimes stopping the bike and starting again would work, or just trying again.  Needless to say, I'm taking it in as I'm not mechanically inclined, but I'm hoping to learn something.  Perhaps a link to a site that explains the problem?

So my questions.

What is going on?  I have heard of something called the "freehub".  I really don't know how bikes work though, so I'm hoping for an explanation of how one can pedal and give power to the wheel and then stop pedalling and the wheel just keeps moving (without the pedals moving).
If you are on a ride, is there any emergency adjustment to make?

For what it's worth, it's an old bike.  Circa 1993 Performance Mtn Bike.  So it's not too surprising that it's falling apart.  I haven't used it a whole lot, and have tried to wash and oil it, but I probably haven't taken the care that a biking aficionado would.  Also, besides losing power after coasting, one time I was pedaling and suddenly the pedals weren't powering the wheel.  I almost went over the handlebars!  So, I definitely want to get it fixed.  I'd just like to know a little bit about what is going on.

Thanks,

Dave.

Bonus question:  If there is enough info to make a diagnosis and you have ideas on costs to fix, perhaps you could comment on whether it's worth fixing.  Like I said, it's circa 1993 and cost about $450 then.  No shocks or anything.  Just 21 speed Mtn. Bike.

This sounds like a issue in your freehub/freewheel (both are mechanically the same for this question).  This is what allows you to coast without pedaling.  Inside these bodies are a set of "pawls" which will flip down and engage a series of splines when rotated "forward", and propels the bike forward.  Then, if you move them in the other direction "backwards", the pawls are designed to be pushed out of the way of the spline.  Given how old your bike is, there is probably a build up of dirt and drying out of grease inside these that are causing the pawls to be stuck in the "up" position and not able to grab the splines.  In this case, your local shop should be able to fix that right up by replacing the part.


How often should the headset be tightened? I live in an area with a lot of potholes and commute daily (between 10-20 miles depending) on a modern road bike. Today while coming in hard (18+mph) to a stop, I went over a worn paving layer with the front heavily loaded. I heard a loud CLACK, and my first thought was to look to the carbon fork. No cracks, but it got my mind on to my head set and head tube. (It was probably just the rear derailleur swinging out and coming down on the B screw.)

What's the minimum mileage interval for headset tightening, and what are the symptoms that indicate it's time? (It's not covered in the Optimal Maintenance question.)

To check your headset, sit on the bike, lock the front brakes, and push forward/backward with your feet. If you can see any looseness in the headset it needs to be tightened.

Since it's so easy to check one should check a few times a year. But no real "schedule" is needed.

I've seen headsets that were remarkably loose.  Though looseness affects handling to a degree, most people don't notice the problem until (in the old threaded headsets) it gets so loose the ball bearings fall out.  Then the bearing grinds and makes handling difficult.


Hoods for 1993 Camapaganolo Chorus levers The hoods for my 1993 camapaganolo chorus levers need replacing.

Can anyone suggest some inexpensive hoods that would be compatible apart from a period Campagnolo part?

The best bet for old Campy Hoods is EBay.

The hoods you are looking for are the EC-R500 Silicone Rubber hoods, I believe.

One set here: http://www.ebay.com/itm/Campagnolo-8-9-Speed-Record-Ergo-Shifter-Hoods-pre-1998-EC-RE500-Genuine-/321946601034


Novice: can I replace this bike trailer clamp with an axle one? I bought this trailer from FB marketplace. I am concerned about the clamp and feel it's not a very safe option.
Is there a way I can replace this easily with a hitch that sits in the axle? Not looking for anything customized.
In worst case, I'll sell this trailer and get something with the proper hitch.
Thank you!

I had one of those - it was convenient because it could clamp onto most bikes, but it always came loose over time.  Once it fell off the chainstay completely, and only the safety strap held it.
So I bought a generic trailer hitch from a local bike trailer builder and used that.  I had to shorten the drawbar by quite a lot to keep the trailer in-line with my bike.  Otherwise it was just careful drilling and cleanup of the burrs, and bolting it all together.
Also I had to fit the towball part to my bike and to any bike I wanted to use as the tractor.  So I bought three, fitted one, have one screwed to a stake for times when I want to mount the trailer somewhere stably, like a bike fixup.  The last towball is spare to loan, if someone wants to borrow the trailer.

Here's two pictures of the coupling.  Its essentially two strips of metal that straps around two sides of the round drawbar, and across the end to provide somewhere for the main bolt to attach.

There's one big grade8 bolt that passes through the end cap and is  firmly retained by a nut.  Further down the thread is another nut which is free to rotate, which allows the trailer to twist WRT the bike.  It won't come off unless the trailer did 20 full rotations.
The up/down and left/right motion is taken up by the towball in its cup.  THere's perhaps 30 degrees of motion up/down and the left/right is limited by the rear wheel/drawbar touching.
Finally the towball is retained in the cup by that sliding cap, which can pull back under hand pressure to allow the ball through into the recess.

The towball on the bike looks like this - its a steel angle plate which goes under the axle nut, and that holds the ball/stem piece.

This is a photo of the towball plate on the bike.

Its a 20" wheel trailer and so is the bike, so sits flat.  If I tow with the bigger wheel MTB then the drawbar ends up pointing upward a little.

A good hobby machinist could make something like this up.  I'd just buy the bolt and nuts.  The hardest thing is drilling/milling and tapping the end piece, and getting the hole to suit the towball, and turning the towball on a lathe.
I have towed a trailer+load of 100 kilograms and the towbar worked fine.  That weight managed to slightly bend a wheel axle though!


Stuck Compression Plug and Top Cap Screw Issue
My top cap screw bolt is currently stuck in my compression plug, and I'm seeking some advice on how to remove both the broken bolt and the compression plug.

This was the top cap I was using:
It's a weightweenie one piece top cap and top cap bolt.
https://www.cycleservicenordic.com/en/products/headset-top-cap/absoluteblack-top-cap-and-bolt-in-one-

What happened
My initial installation of the top cap wasn't perfect for the preload.
Symptoms appeared in the form of loose headset and the top cap bolt becomes stuck.
Tried to unscrew top cap but didn't work.
Eventually the T25 top cap bolt stripped.
Used Araldite in the bolt and on my T25 key, left it over 2 nights, still didn't unscrew.
Hence my diagnosis was that during installation, there was cross-threading. But does it explain why it is so insanely difficult to unscrew? Not sure.
Then came the drilling.
My plan was to drill off the top cap, then use some pliers to turn the remaining top cap bolt.
Look where it got me, there doesn't seem to be any top cap bolt left.
Specifics
It's a Bianchi Oltre XR4 fork.
1-1/8inch steerer tube. Rim brakes (no hole in steerer tube).
Compression plug was torqued to 6Nm. Top cap was just lightly hand tight.
Compression plug is from Aliexpress and looks like :

Parameters
I am not planning to reuse the compression plug so it can be destroyed.
Steerer tube can be cut about another 4-5mm.
Seeking your wisdom
I'm not sure if there was actually cross-threading or that the metallic surface somehow fused together (not entirely sure if compression plug is steel or alu).
Please teach me how to remove the whole assembly out of my steerer tube.
Thank you, the Feynmans of the bicycle world!

Thanks for all your help!

What worked
Drilling with a small bit into the edges of the broken top cap screw.
Miraculously, I noticed that the screw loosened itself as it's unwinding little by little from the vibration of the drilling.
Then I used some pliers to unwind it out and was able to find a near-perfect hexagon hole where I can stick my 6mm in.
Mis-diagnosis?
So...the top cap screw thread doesn't seem to be burred or damaged. Even cosmetically it looks fine.
The black anodising on the thread is consistent and no bubbles or cracks can be seen.
But I'm actually really curious, and want to prevent this from happening again!
Please leave your thoughts below so we can learn more from my mistake together.
Did I start the drillium too early? Was there another solution?
TLDR;

Loose headset, and top cap bolt stuck.
T25 top cap bolt stripped.
Araldite in the bolt and on my T25 key, left it over 2 nights, didn't unscrew.
Top cap bolt is aluminium, compression plug bolt is steel.
Drilled off top cap, left an even more stuck top cap bolt in compression plug.
Drilled out top cap bolt, bolt seems perfect.
Please tell me why top cap bolt is even stuck in the first place.

Thanks @Michael and @Carel.
Guess drilling really helped in the end!


How to remove skid marks from fabric What is an effective yet safe way to remove skid marks from fabric originating from keeping a bicycle on it?-- The back tire of my bicycle has been standing on a piece of rug and I need to clean the rug now (I didn't know I should have kept the rug clean until it was too late):

In a similar situation - bike tire marks, trainer residue and grease spots on the carpet - we found that scrubbing the carpet using a concentrated dish detergent (like Dawn, etc) worked very well.


Is it better to have less flywheel weight on exercise bikes? Is the workout quality better when using an exercise bike or trainer with less flywheel weight?

With less flywheel weight such as a bicycle on a trainer as opposed to spin bikes, coasting is harder. This should make it easier to learn to pedal smoothly and not coast which are encouraged. Because our muscles work longer, it seems like it's more effective for improving our endurance for the same workout duration and getting more exercise out of the same amount of time. We might expect working our slow twitch muscles more and using our fast twitch muscles less.

If dead spots make it an issue, can shorter cranks or oval chainrings be substitutes for flywheel weight?

Update:
When I say pedalling smoothly, I meant in terms of power output throughout each pedal stroke.

With a smoother pedal stroke, would it actually decrease normalized power?

Workout quality is determined by the power output you can sustain through the course of your effort(s), and if the power is lower than it might be because of a lack of crank inertial load, then the training stimulus will be less.

Keep in mind that the most important adaptations are metabolic, not neural. Changes to pedalling action has not been shown to convert to improved power output, except for the specific situation being trained.

It's common for people to find riding on low inertia trainers (e.g. cheap magnetic resistance units) unable to generate the same power as when riding a high(er) inertia trainer. The crank inertial load doesn't need to be as high as that experienced in typical outdoor riding, just sufficient to avoid that awful draggy sensation.

There are quite a number of published studies about varying crank length and chainring shape. The balance of evidence on these is that on average, such interventions neither harm nor enhance your sustainable or maximal power output.

As a general rule of thumb, if you find using a trainer results in a power output 10+% less than you would ordinarily be capable of, then I'd suggest looking at making changes to your trainer set up. That may or may not include increasing the crank inertial load but often means paying attention to other factors such as having adequate cooling (very important) and use of motivational aids.


Is possible to mount an existing freewheel on a fixie wheel? Would it be possible to mount a freewheel from an existing wheel on thie following type of wheel made for fixies? Or do I need a different axis for the rear wheel such as the one below?

The axle (the object on your picture) does not define which types of cogs can be used. It is the hub that rotates around that axle that determines it.
The flip-flop hub of the wheel you are linking to is designed to take a single speed freewheel (used also on BMX and some single speed city bicycles) on one side and a fixed cog on another side. It is not designed to work with multi-speed freewheels.
A simply longer axle is unlikely to help, as there are many other factors that define the compatibility. Among them are:

The axle itself. Its diameter and bearing types/dimensions must match the hub body (i.e., if the hub has cartridge bearings, loose ball bearings and a cup-and-cone axle will not fit it.)
Hub width. The fixie flip flop hub is 120 mm wide. Some of  multispeed freewheels require 126 or 130 mm widths.
Wheel dish. The multispeed wheel is more asymmetric because it has cogs only on one side, while a flip-flop hub has similar free spaces for cogs on both sides. A wrong wheel dish means the rim and the tire won't sit in the central plane of the bike but more on one side of it; as if that was not bad enough, it may also cause the tire to rub against the chainstay.
Threading pitch of the freewheel must match the hub threads' pitch. That is something to keep in mind even when changing single-speed freewheels.

More about freewheels: https://www.sheldonbrown.com/freewheels.html


why are my disc brakes shuddering I have just replaced my disc brakes with avid bb5s. The braking is fine but there is a severe shudder, especially when braking hard. Any ideas?

Thanks for your responses but I have solved the problem. The online parts store provides only one bracket for front or rear. The front brake actually requires a shallower bracket, so the pads were skipping across the cutouts in the disc. The LBS was able to supply me with the proper bracket and the shuddering went away.

Pick up the shuddering wheel(s) and spin them to make they are "free", i.e., no brake contact when the lever is not depressed.
Check that your wheel axle is securely seated in the dropouts.
Check that your hub is tight -- pick up the end of the bike with the shuddering brake, push side-to-side on the top of the wheel. You should feel no play or a minuscule amount.
Check the brake rotor for trueness. Spin the wheel, looking in where the rotor goes between the pads. Is the rotor staying in pretty much the same point between the pads, or going from side to side? Alternatively, or additionally, you can spin the wheel and slowly depress the brake, to see if the pad-rotor contact happens first at just one "high" spot or if it happens more or less evenly.
Center the caliper. Loosen the caliper position bolts, grab the brake lever, and then tighten the position bolts.

That's what I'd do to start. With more information I (or someone else) might be able to help more.


which is better a sram 11 speed or shimano 10 speed FD with shimano 105 11speed groupset I have bought an 11 speed shimano 105 groupset, unfortunately the 11 speed FD does not fit my bike (It is an Airnimal Chamelion).  Therefore I have a choice of Sram 11 speed FD or Shimano 105 10speed ?

please advise which is best?

Unfortunately, you should be using a 11 speed Shimano road FD with a 11 speed road Shimano shifter. SRAM will have cable pull issues.

According to Zinn, "a Shimano 11-speed shifter will not work well with a 10-speed front derailleur because the 11-speed shifter is designed to actuate the longer lever arm of Shimano 11-speed front derailleurs." so that cuts out the old days where you didn't have to match the front shifter speeds with the front derailleur.

So, you need to find the right Shimano 11 speed front derailleur for your frame (you're looking for "Shimano 105 5800 Braze-On Front Derailleur" (Shimano FD-5800-L) since the Airnimal Chameleon seems to have a Braze On FD).


Cable/cord near brake level is extremely loose, brake doesn't work When I press my left brake lever, nothing happens. I looked and the cable is loose. It comes completely out of the little silver thing on the left side of the handle. (left when looking at pic)

The actual brake lever also moves too far.

(I am a literally newbie at this. I have NO idea whats' wrong and google isn't smart enough to help a bike idiot like me.)

Make/model = It's a V brake Shimano "V-Brake". For bike it's a Raleigh 4.5

Had my bike worked on again today and now THIS is an issue.... :(

Update: Picture of the area near the wheel. This is where I suspect I need to do something. This is where it is "really" loose.

Yep, the V-brake is improperly assembled.  The curved metal tube is supposed to "catch" the end where it touches the rubber accordion thing in the notch in the dohickey attached to the right-hand-side brake arm (which is on the left in your picture).  Either it got knocked out (possibly while the bike was being put into/taken out of your car trunk) or the notch has spread (unlikely) letting the tube slip through.

Here is a picture of how it ought to look.

(Note that the brake is designed to come apart at that point.  This allows the arms to be spread apart to make it easier to remove the wheel for service.  In fact, it's not too unusual for a repair tech to forget to reconnect this after servicing a bike.  Or it may have been loosened to remove the wheel while transporting.)


Cycling traffic signs and rules in Germany I'm over 30 and have just started cycling in real traffic, my first experience, as I have only ever ridden as a child in parks and such. I live in a university town in the state of Baden-Württemberg in Germany. Unfortunately, I have no clue about traffic signs as I neither drive nor hold a drivers license. Could someone recommend a place where I can learn about the traffic signs for cyclists, what they mean, the rules for cyclists, safe riding guidelines, etc? I have tried reading the legal rules, but my German is basic and those make my head hurt. Perhaps a site with photos of signs,simple language (either german or english)would be wonderful. I hope that all the cycling enthusiasts here can help me ride safely and correctly.

You might consider contacting the ADFC (Allgemeiner Deutscher Fahrrad-Club). It is an association specifically for people who cycle as a means of transportation (rather than as a sport - though of course the two are not mutually exclusive).

They are part service organization, part environmental organization. They have local groups (Kreisverband / Ortsverband) in almost every city, which usually have regular meetings. Contact your local group (or just go to the local meeting); they will be very happy to give you hints, share local knowledge etc. (even if you are not a member yourself).

Many local groups even have explicit meetings for people new to the area, or new to cycling in general, where they try to pass on useful knowledge.

For a list of local groups: ADFC vor Ort

They also have a lot of general information on their website. See e.g. Sicher unterwegs.

Note: Most stuff is only available in German, but I hope basic German is enough to read it. Local groups will be German as well, but many people will speak some English.

Disclaimer: I am an ADFC member myself, and have been active for several years.


Steerer tube shims for quill stem? My current stem is 25.4 mm in diameter. It's way too low and long. It's a threaded fork.

I have a nice quill stem adaptor that's 22.2 in diameter that would be nice to use.

Are there any shims to go from 22.2 to 25.4 and is it worth it?

I found some from Problem solvers but it seems to be for threadless stems only.

what would you do? would a shim be safe here or is it a no-do?

UPDATE: I found a shim and installed it. It works really good. Much better than my old crappy quill stem.

Threadless quill stem adaptors do commonly come with a shim, so that they can be used with either size steerer, e.g.
http://harriscyclery.net/product/velowerx-universal-stem-adapter-quill-to-threadless-5423.htm

I've never seen such a shim sold separately, but a search shows up https://www.amazon.co.uk/Alloy-Aluminium-Quill-Adapter-Quillstem/dp/B00K7ECRLO, which is currently unavailable, but was sold at some time, so you might find one.


What to look for in bicycle travel cases My wife and I are taking a trip to Japan in several months and that got me thinking, what should someone look for in a bike case when travelling? I won't be taking one on this trip (not in the shape I want to be in quite yet), but it could be beneficial information for others and myself in the future. The range of prices that bike cases span is pretty broad so knowing what to look for could potentially save you money and a broken bike.

Doing a little bit of research myself, I noticed that some airlines will also supply you with boxes for travel. Are these safe or is it worth getting your own?

Bicycling in a foreign country (or a different city for that matter) seems like an amazing way to see parts of it that you normally wouldn't get a chance to see.

Make sure it is sized to your bicycle.  The one time I flew a commercial airline with my bicycle I planned to use my father's travel case.  But with the wheels, cranks, seatpost and handle bar/stem totally removed my frame would not fit.  (A 64cm road frame).

Because it was for a one time, one way trip I got some shipping boxes from my local bike shop.  I got creative with the foam and packing tape.  Bike made the trip just fine :)


Help identify this Raleigh bike New to Bikes so hoping this question is OK.

My partner was recently given an old Raleigh bike for free and has since taken it to get the cables and tyres replaced, but as it's quite small (for teens?) she plans to trade / swap / sell it for something more her size.

I know nothing about bikes whatsoever, but apparently the people in the repair shop said it's quite unique. Can anyone tell me anything else about it? Era / 'model' / history or the like?

The Jeep is a giveaway.  There really was a Raleigh Jeep.  It's on page 7 of this 1971 catalogue.

You're right, it was meant for girls.

That massive headlight isn't original.  Otherwise it's a nice looking bike that needs some work.


How to fix cross-threaded derailleur hanger? I've removed my rear derailleur so many times that I think I messed up the hanger threading this latest time I reinstalled it. It's very hard to screw in, doesn't even go in straight, and now not even my hanger alignment tool screws in properly. Since my bike is so old, I just bent the hanger to account for the miffed threads and reattached my derailleur the best I could as a temporary fix. Now I want to fix the threads. I've since learned of some methods involving tapping the threads as well as drop-out savers:

How To tap and Clean Threads On Your Derailleur Hanger

How To Fix Derailleur Hanger With Stripped Threads

Based on my description, is it likely that I cross-threaded the hanger? If I need to resort to tapping, how do I determine the proper tool to use? Are there bike-specific tools or will pretty much any tapping tool work so long as the measurements are correct?

If its a replaceable hanger, simplest option is replace it.

If not you might be able to repair it with a 10mmx1mm tap. If that does not work, a Helicoil type repair is possible. Its one of those tasks if you are not 100% confident you can do right first time you might be better off handling over to a shop (An engineering shop or well equipped bike shop) as it is possible to make it worse.

Refer Park Tool Basic Thread Concepts


Has anyone tried this "poor mans" homemade electric bike idea? I have a wiper motor from some car or van that has a shaft on it.  When I apply 12 volts to it, with no load on it, it seems to spin at about 125 RPMs.  I vaguely remember that when I load it, it can draw up to about 10 amps (10A).  I suspect it can output maybe 100 watts of power or so.  It also has 3 mounting holes.  I suspect someone mechanically inclined could perhaps connect this with 1:1 ratio to the crank/chainring assembly.  The 125 RPMs would likely drop under load but under low load it should maintain close to that I would think.  It would be fun to try it with some type of freewheel mechanism or centrifugal clutch so when the motor is turned off, it would not load the cranks.  Since the rotational speed mimics a normal cadence (probably will drop to 60 to 100 RPMs under load), it can possibly be used to run a multispeed bike and if the rider pedals too, they would help each other out (like 100 watt motor plus 100 watt rider = 200 watts total).

So has anyone ever tried this and do you think it could work and if you think so, do you think it would work well?  What about pitfalls?

UPDATE: I tried the motor with a 12V battery and a short crescent wrench and I was able to hold the wrench still but there was a fair amount of tug on it, meaning it might be ok as a helper motor but not strong enough to move the bike on its own.  It would be interesting to see if after getting the bike going say 10 MPH, if this motor would at maintain that speed or at least help the bike to coast down longer.

Also since it spins at about 125 RPMs, it can be geared down even more such as thru a 16T drive sprocket and a 20T driven sprocket which is a a 4:5 reduction so then about 100 RPMs, giving it more torque.  I think if this motor spun at half the speed, it would be harder for me to hold that wrench still.  Maybe some other wiper motors spin slower like 60-100 RPMs.

Thank you.

No I've not done that, and it would likely be a bad choice for an ebike conversion due to lifespan of motor.

Electric motors have an optimum rotational speed which depends on their design and the number of coils on the armature.

Your wiper motor will have a speed of around 2000 rpm, and it will drive a worm gear - see the excellent photo in @Frisbee's answer.  That worm gear will drop the output RPM to 1/50th  or about 40 RPM.  The output will be a low speed and high torque.  This means the motor wants to spin at a fixed speed, not faster and not slower.

A wiper is also driving a cable or rod system that has half a kilogram of wiper blades attached, compared to the weight of a bike plus rider.  So there's the duty cycle to consider too-how hard the motor has to work.  Remember its a brush based permanent magnet motor intended for forward-backward-stop duty in a relatively cold environment, so running it hard out is not a good idea.

Finally, you'll need to fab up some way to mount the motor and apply drive to the bike.  Your options are

Front or rear hub - not suitable for home job, need to build motor into wheel hub
Tyre drive - possible.  The motor has a roller and pushes that against the tyre creating drive.  Wears out your tyre in triple-quick time.
Mid drive - Attach the motor to the drive chain by a cog and mounting plates.  Downside this messes with your legroom, but may allow the use of rear gears still.
Offside drive - Some of the liquid motor kits add another drive cog on the left-side of the rear wheel, and run a second chain.  These can't pull away from stopped because they lack a clutch, so you need to pedal up to speed before engaging the liquid engine.    This technique would leave the freewheel clicking when pedals are not providing drive.

You also need to consider batteries for an ebike.  Mine had 3x 12AH 12V batteries mounted in the frame, and all up the bike was about 28 kilograms.
More details at http://www.electric-bike-kit-forum.com/post2249.html

If you wish to electrify a bike, consider a kitset from somewhere like  http://www.electric-bike-kit.com/hill-topper.aspx   The $800 USD ranger seems decent, and you can revert your bike to normal by taking the kit off.

It looks like you're not the first to have this idea though.... http://www.autospeed.com/cms/article.html?&title=Building-an-Electric-Bike-Part-2&A=111538
Note he had to build an airscoop to cool the motor, and a powered fan for when stopped.  That's a friction drive too, so uses up tyres fast.

Finally - your locality will have some restriction on the maximum power motor you can fit before your bike becomes classified as a motorbike.  In New Zealand its something like 250-300 watts which is good for about 20 km/h maximum.

Now I can exceed my electric bike speeds by riding my road bike, so I sold the ebike parts and use the old MTB for towing my bike trailer.  Consider upgrading your own motor by biking more for health and fitness.


What is a reasonable speed for long distances on a bike? I am curious what a reasonable speed to travel on a bike is.  Speed will obviously vary based on the conditions in which you are riding.  I am planning on taking the GPS out with me this weekend to see how quickly I go.  Before I did that I wanted to get some benchmarks.

For the most part I will be riding an older road bike on crushed rock.  (Very small rock, with good rolling resistance but still much worse than pavement).

I will also be riding that road bike on the road (i.e.: pavement in North America, Tarmac in Great Britain).

What is a reasonable speed on these two surfaces?  I am more interested in speed over long distances, i.e. if you were going 80 km what would your target speed be?

Speed varies widely by cyclist, depending on fitness, road conditions and traffic.  Some of my observations (cruising speed based on a flat, paved road in good condition):

20km/h (12.4 mph) - many "occasional" cyclists ride around this speed
25km/h (15.5 mph) - most commuters
30km/h (18.6 mph) - fast commuters, slower roadies
35km/h (21.7 mph) - fast roadies
any faster than that on a long flat and they're probably a racer

(based on who I pass and who passes me when riding around 30km/h)

Average speed will usually be slower than you think, once traffic stops and hills are factored in, especially over longer distances (like 80km).  On my 21km commute I'll hit 30+ on every long stretch I can, but my average still only works out to 24km/h.  For longer rides I cruise around 27-28 km/h, which is more sustainable; averaging 22-24 over a very long ride (200km) is a great pace for me.


Can I fit a 32-630 tire on a 20-622 rim? I know that the width difference might present problems later on, but if I understand correctly then it should be possible. The bike isn't meant to be used in high performance circumstances, just the city.

However, if I understand correctly, the tire would have a larger diameter than the rim. Is that likely to cause me much trouble?

tl;dr If I have a 32-630 tire and a 20-622 rim, can I make the combination work?

No.  The bead seat diameter (inner diameter) is different by 8 mm.  You cannot shrink a steel or Kevlar bead by 8mm, as they are designed not to stretch  or shrink (otherwise a clincher tire will roll off the rim in a corner).   You can try but the tube will burst out from the extra space.

The tire bead is what interfaces with the rim.


Is it possible to mount Shimano Ultegra 6870 Di2 on a 2012 Cannondale SuperSix? I was just wondering if it was possible to fit the 6870 Di2 on a 2012 Cannondale SuperSix ? It has no internal wiring. I think the 6870 Di2 has a new round long battery that only goes in the seat post. I don't think I could get a wire out of the top of the seat post.

Here is an internet picture of my 2012 cannodale supersix

I was told on another forum that the battery should fit the seatpost.

I guess I could drill a hole in the frame but it would void the warranty.

I wouldn't modify a carbon frame as it'd be difficult to detect the beginnings of delamination where you drill it.

Internal wiring is optional. You'll need an SM-JC40 for external wiring, a SM-BTR1 and SM-BCR1. The charger which connects to the front junction will only charge internal batteries.


How to reset pistons after replacing brake pads I recently replaced the brake pads of a Tektro Dorado system.
But now I cant hardly turn the wheel, the clearance between pads and disk is too small.
Bleeding wont help, that's only to remove air.
The auto adjustment (wear correction) must be reset, but how?

Thanks

Usually you can just push the pistons back into the calipers.  Remove the wheel, remove the pads. Get some kind of tool suitable to prying, such as plastic tire levers or a wooden lever.  Insert it between the pads. Push/pry slowly and firmly and the pistons should retract.

I've read that metal tools (e.g. screwdriver) are not recommended because they might scratch/chip the surface of the pistons. I don't know if this is an issue with metal pistons, but more likely to be a problem with ceramic pistons.  Perhaps someone can correct me in a comment if I got this wrong.

I've done this with Avid Elixir 5 brakes. I don't know if all hydraulic brakes work this way.

I've had cases where this doesn't work, and the solution was to remove a small amount of brake fluid.


What type of brake is this? Update -

As Daniel pointed out in the comments below, this is an unusual type of roller cam brake that is fixed to the fork using a single bolt through the fork rather than cantilever fixings

I have found two examples of roller cam brakes that uses a single bolt - Odyssey Bulldog and Dia Compe Big Dog - but both seem to have been discontinued for a long time

I will leave this question as unanswered a little longer in case anyone know of other brands that make these brakes that are currently available

I have a long reach brake that I've put on a refurbished old Chinese bike, it looks fantastic and it's a perfect fit for the old fork and new 700c wheel combo that needs about 95 mm reach

I am looking to refurbish another old bike, but I can't seem to find this type of brake anywhere. The one that I have came from the Taiwanese stockist Ducas (www.ducas-bike.com), but they no longer have it in stock and they have not been able to help me find one somewhere else

Any help identifying this type of brake or a good long reach alternative (I need at least 95 mm) would be much appreciated

As stated by Daniel R Hicks, these are roller cam brakes.

Sheldon Brown sells a few extra long reach brakes: the Odyssey 1999 Extra Long Reach Caliper Brake and the Action© Extra Long Reach Caliper Brake. Tektro C-326 seems to have adequate reach, but the problem is since its designed for beach cruisers, the rims have to be quite wide. I don't know if the other brakes listed have this problem.

A relatively easy solution is a drop bolt, which is a device which allows you to mount a brake lower than the frame is designed to. You can make a drop bolt and use a regular reach brake instead of hunting down a 100 mm reach brake. These are reasonably common with the Raleigh Twenty crowd, for example. In the picture below from Sheldon Brown, he has a Raleigh Twenty with a short reach caliper!

(Image from Sheldon Brown)

Note that this is a hack, so its YMMV/at your own risk.

A real drop bolt looks like this:


geared to fixied options I've got a geared bike back tyre that has a dent in the rim. I'm considering a fixed gear conversion. A few points of issue:

The bike has small vertical drop outs.

The skewer width on the current back tyre width is for a 7-speed block.

What are my options to deal with these issues?

No EBB, vertical dropouts, and 130mm spacing in the rear. You have a few options. Here they are, from worst to best, and most likely cheapest to most expensive.

 Ghost ring. Basically, you get your chain length as close as you can then cram an old chainring in the chain inside the chainstay. Scary solution, especially if you don't run (all of your) brakes.
Magic Gear. Find a gear combination and chain length that gets the chain respectably tight. May require halflinks, and can be a PITA. If if works, it works great for a short time, then the drivetrain wears and the chain becomes loose and you have to do it all over again. Not a great permanent solution.
White Industries ENO eccentric rear hub. This is the way to go if you're willing to spend the cash. Comes in a variety of spacing, free or fixed threading. Works basically the same way an Eccentric Bottom Bracket does. Dropout bolts are offset from the axle so it allows you to adjust the distance from the bottom bracket to the rear axle. White Industries makes bombproof components as well.

My recommendation is the ENO, hands down. Don't bother with your current rear wheel. It's more trouble than it's worth.


Disc brake rotor compatibility and recommendation I have Ultegra BR-RS805 flat mount hydraulic brakes on my gravel bike, and Shimano RT86 6-bolt Ice Tech 160mm rotors.

There's a shim between the brakes and the frame to fit the 160mm rotors. When the guy at my LBS looked at my bike, he held the brakes and rocked it back and forth and said there was a lot of movement on the back wheel due to the shim and recommended that I use a 140mm rotor instead so I could remove the shim. As I have another set of wheels I'm building out for the bike, I thought it made sense to get a pair of 140mm rotors and then use those on the two rear wheels, with the 160mm rotors on the front.

As the RT86 rotor does not come in a 140mm size, would a 6-bolt 140mm SRAM Centerline rotor be compatible and a good option?

This doesn't answer your question, but your problem before the question.

If your brake body is moving about, the problem isn't the existence of the shim (which is used by all brakes when they upsize) but either:

the bolts holding the shim/adapter to the bicycle or the brake to the adapter were not properly torqued and loctited.
the bolts holding either the shim or the brakes are too long and are bottoming out so they can't lock down properly
the shim was poorly made and has a defect that is causing it to move
your bike store is either incompetent or trying to upsell you something

Note that brakes are supposed to move when the bolts are slightly loose so that you can properly center the pads against the rotors. Then you clamp them down to the proper torque tolerances.

Since most people want to go up in rotor size to have more effective braking, you'd be bucking the trend in going down. Are you 100% confident in the mechanical skills of your LBS?


Can an Alfine 11 replace a Nexus 8? An online store currently offers the Dahon Curve XL with a Shimano Nexus 8 IGH (The Dahon site shows the Nexus 7 model).

I'd like to replace it with an Alfine 11.

Does someone know if the OLD (Over Locknut Distance) is the same, and whether it could be an easy replacement?
http://www.sheldonbrown.com/nexus-mech.html

Thank you.

As @Kibbee has stated the IGHs do have a different OLD, although Nexus hubs can be spaced out to 135mm with spacers/ bolts/ washers.

You need to measure the Dahon's rear dropout spacing.

I can't find anything to suggest otherwise so I assume it's 132mm, in line with other commuter type bikes.

The limiting factor is dropout spacing. The Dahon is an aluminum frame with short chainstays. Both of these essentially prevent the ability to spread the dropouts and force a wider hub in. Aluminum is brittle and not malleable like steel, it doesn't like being bent.

You may damage your frame and void the warranty.


How should the chain be routed on this deraillier? I feel dumb asking this, but how should the chain be routed around the cogs on this deraillier?

I had to split the chain and then put it back on. I didn't pay attention to how it went round. This is not the right way (below) as the chain is extremely slack.

You almost made it...   Obviously bottom long line should run straight to crankset.  You will feel some spring tension when you route the chain.


Tube slowly loses air A few weeks ago I noticed that my bike tube slowly leaked out air over the course of a day or 2. I bought a new tube and it does the same thing. I checked in water and saw no leaks.

9/10 it’s a tiny sharp object like a sliver of wire stuck in the tire. Take the tube out of the tire, pump it up really big, run the tube through your hand until you feel where the air is coming out. Then look at the tire in that spot and find the thing that poked a hole in the tube.

Alternatively, switch to tubeless and don’t worry about small punctures anymore.


Saddle started to hurt after years of riding Recently I began having problems with my saddle, or more precisely, my behind. It starts to hurt where my sit bones are after 45-60 minutes. It feels sore at first, but eventually it gets really painful. I've ridden this bike (Trek Madone 5.0) thousands of miles over the past 10 years, but the pain only showed up in the past two or three months. I had a complete professional fitting when I bought this bike. I've changed nothing, and until now it's been perfect. The saddle is the Bontrager Race saddle that came with the bike.
At first I thought it was my shorts. I had some high end shorts that I thought might have worn out, so I got some new shorts that seemed to help at first, but now it's back to the same pain in the same place.
Twenty years ago I was a 10,000 miles a year rider, splitting my time on road and mountain, and I never had this problem. Back then I would be on my saddle for seven hours, and I never had this problem. Today, I'm more like a 3,500 miles per year rider, but I can barely do one hour in my saddle without pain.
I don't have the same pain on my mountain bike, which has a Fizik saddle.
I was looking at new saddles, which might be a solution, but before I do that, I figured I'd seek some advice here. Maybe it's a fit issue? Something changed unknowingly? I know my way around bikes pretty well, but I don't know anything about body mechanics.
Any advice?
Okay, adding some responses to the comments:
The Fizik saddle (MTB) is almost 20 years old. That really surprises me, but it's a 2001 Santa Cruz Superlight, so it must be. That bike still feels new to me! That's not the problematic saddle, however. The Bontrager saddle on the Madone is.
I have lost 15-20 pounds in the last year or so. I thought that might have something to do with it. That I might have less "padding" on my rear, but would that last 2 months? I should have adjusted by now. I'm riding four to five days a week now.
I did a quick check of the saddle. There is nothing obvious that is cracked or broken. Bolts are tight. I twisted and pulled it, but I can't get it to move.
I think the solution is to get a new saddle.

Whether we like it or not, we all change every moment. Because we are alive. The differences are slight, but they are cumulative. Any change in activity, diet, lifestyle, etc. changes our body. Saddles are only getting old.
Pain isn't just an inconvenience - it's your body's way of talking to you:

constant little pain when you get tired of translating: 'enough for now, I'll fix minor problems',
increasing pain: 'stop, at least slow down, I need more time to fix myself'
muscle pain the day after training: 'you did it wrong, don't force it anymore'
sharp pain: 'STOP !! Never do that again'

If your lifestyle has changed to be less active:

you have smaller muscles and you sit differently
you slouch - your spine is overloaded and you sit differently

If you have lost weight:

you have too little weight to use the suspension perfectly
Your skin is not sufficiently isolated from the bones
Your skin may be too dry to deal with it
you have a different weight distribution
you sit differently because your body is different

If you have gained weight

you have a different weight distribution
you sit differently because your body is different

Check the saddle - even a 1 degree incline can make a difference, it's a long saddle.
Check your ... body - take 2 mirrors and look at them - you may have a new sign (no it's not cancer, cancer is vicious because it doesn't hurt until it's too late). If you find anything unexpected, go to MD and have it removed / healed.
All of the above can occur together.


SRAM replacement dub crankset, is this pre-greased? I'm replacing the NX cranks on my bike with X01 cranks, all of the install videos I've seen show people greasing the cranks but these look like they're pre-greased. There's blue/green stuff on the spindle and brown inside the socket on the crank as per the pictures.
Is this grease and is this sufficient? Should remove it and replace it with this grease I have?
My old spindle didn't seem to have very much grease at all and it was black so difficult to compare.

Yes that is grease, in my opinion that is about the bear minimum amount intended to help prevent seizing between the two interfaces. I usually leave it if it is my own bike and just add a bit more additional grease, as most cycling greases will not have any interaction with each other. In a professional setting or working on someone else's bike I would remove it and use all one type.
If you watch Sram's installation videos they are definitely a bit more liberal with the application spreading it both on the exterior of the spindle, and in the grooves that interface with the crankset.


What kind of German bike is this? I want to buy this second-hand bike but the person selling it lives in a different city and I can't go there at the moment.
However I can't explain it but I really like the bike even though I only have this picture of it.
I would like to know if any of you recognize the bike.
The only thing I know about it is that the bike is German.

OP's answer-as-a-comment:

  The bike was not german, it was japanese. I found that the derailleurs were made by DNB Japan somewhere around 1960 and that the handlebar is french (Guidon Phillipe), but other than that , this bike is a mistery to me. The brakes only have a logo on them and the frame has only a number and a logo on the back. Underneath all the black paint, in the front, is a sticker but there is no way I can peel just the paint without damaging the sticker... On the pedals it says Lyotard 82 and they are in a rather good condition.

Thus, it is not identifiable.


Bike repainting options I'm based in Oxford and I have a classic Triumph steel cruising bike. I am a complete amateur when it comes to paintwork and I wanted to ask the community here a few quick questions if possible.

The pictures I have attached are probably the most useful but I will explain what I think is going on with the bike too. There is lots of patchy paint loss dotted all over the bike with exposed steel that I would like to protect and repaint if needed.

My main question is... What are my options to try and prolong the life of this frame? I ideally want to preserve the Triumph logos too.

Many thanks,

James

Steel requires rust proofing. Just like on you car, there is a thin layer of primer under the top color. When scratched to the base metal, sanding and painting the affected area is necessary.

Sand until the exposed metal is shiny. Depending on the spot, you can use a high grit paper, or wet sand paper with water. You might want to start with 200-300 grit and then maybe 400 or 600. You're working with a small area so you don't want to press hard when sanding.

A good technique to make sanding with paper easier is to fold it a few times to get into tight areas. Folding gives you a stiffer sheet edge and you can work it in crevices. Also wrap an inch or two of paper around a woodend dowel, or even a pencil. A round shape will help you sand the long vertical scratch on the fork without having to sand the whole width of the fork surface. The round shape will only touch the suface in a long thin area instead of a wide area.

Wet sand paper is usually less than a dollar at most hardware stores when bought by the sheet instead of the pack. You shouldn't need more than a sheet or two of each grit. Wet paper last a lot longer than dry. It can also be cleaned/washed.

Use a high percentage alcohol to degrease and remove dust after sanding. Dry thoroughly if wet sanding before using the alcohol.

Then prime, even if it's just dab priming. Allow the primer to dry thouroughly and lightly sand the primer back to where the original paint just shows around the wound. You can also use a high number wet sand paper with water to lightly sand.
Look for a paint match at an auto parts store. Dab the paint on primed areas and let dry. Wet sand with high grit paper to match the original finish. Treat the paint like a regular car. Small amounts of paint polish will give you a good shiny finish with little work. Apply wax and enjoy. Paint like yours should last a long time.

1) Rough sand with shaped paper to get the rust off down to the metal.

2) Wet sand for a finer surface finish.

3) Dry, then degrease with alcohol.

4) Paint with primer.

5) Sand the primer and lightly dust with lint free cloth(cotton ball or pad) and alcohol.

6) Apply matched paint.

7) Wet sand with fine paper.

8) Wash, then polish and wax to shine.

9) Enjoy for years to come.


Enduro MTB or Downhill for 14 year old? I'm not sure which one to get. I'm 14 and will hopefully be getting into downhill but I'm not sure if I want to go all the way. This is my first full suspension bike.

Enduro or AM (All-Mountain) mate. They are more versatile, especially if you don't know if you are going to stick with DH.

These days, DH bikes only do one thing. If you don't know what that is or haven't been hooked yet, move the cash to an AM. A half decent AM bike will be a handful already for any novice.

Plus you can pedal back up and you will enjoy that more than waiting for adults to drive you back up.


Gears keep auto dropping esp in hills My bike is 10 years old and has Shimano ultegra triple crankset.

Being my first road bike, I assumed it was my skill when the gears would drop on their own or kick the chain off. I took it in to shop several times and the mechanic would tinker with the derailleur or other parts. I have changed the chain a few time but the problem never stops.  Suggestions?  I am at the point of just getting all new crankset.

changed the chain a few times

Have you also changed any of the corresponding drive-train ie. cassette and / or chainrings?

Check the wear on your cassette. If the teeth are thinned-out the cassette is also worn and you will need to replace this also.
Check the chain-rings - if these resemble shark-fins these are also worn out.

Unfortunately drive train wears together and replacing one part of them often creates a skipping gear where the chain no longer sits comfortably on the drive train due to previous wear.


Specialized frame warranty - cracked Alu seat tube I have a Specialized Allez Sport 2012. Which I purchased, new, just under 6 years ago in the UK. The aluminium frame has developed a crack in the seat tube, just above the brazed on derailleur mount.

I note the newer models of this bike have reverted to a band on front mech mount. Is this because cracks like mine are common, possibly caused by a recognized design flaw?

Whilst I understand aluminium frames have a fatigue problem it isn't the type of crack I would expect to see. The bike has done just under 10,000 miles.

Am I likely to get a replacement frame under the lifetime frame warranty. If so how long is it likely to take?

Reading the current Specialized warranty policy I'd say you are covered.

Only one way to find out for sure though - contact Specialized and ask to make a warranty claim. You will find out if they will cover it soon enough.

Unless someone here has been through the same process recently it's hard to say how long it would take.


I got a new inner tube but it's letting air out I've tested the new inner tube overnight, to check whether it's letting air out, and it does. Is the tire damaged or the inner tube?

This is hard to tell from the outset, but:

Have you checked the inside of your tire before you put it back on? If it contains a piece of glas it will puncture the new inner tube. Just remove it in that case. The only reason to replace the tire would be if it is worn down and for that reason you can expect to have another puncture soon.
You might have damaged the new inner tube when fitting it. You will need to take it out again and inspect it and it will become obvious, if that was the case.
The valve could be the problem especially if the loss of air is very gradual. Put the inner tube into soapy water to find the leak.

In summary: take out the inner tube, find the leak, and inspect the inside of the tire before putting in a patched or new inner tube.


Mtb tires on road rim I got a mountainbike from wich the back wheel completely bent. I can't fix it with a spoke wrench. The tire is a v-brake tire and I had a spare v-brake rim laying in my shed only problem is that it had a road tire on it.
So my question is: could I just put a mtb outer tire on that v-brake rim with the road tire on it and succesfully use it on the trails?

Assuming the new rim is about the same width as the bent one, then the tyre and tube should transfer over okay.
You need to check the valve hole in the rim - there are two common sizes, and the wrong one won't fit or risks punctures at the base of the valve.
I suggest you fit the tyre, and inflate it to a relatively high pressure, whatever's maximum on the sidewall.  Then leave it overnight and check again in the morning.  If it holds air and hasn't blown off the rim then deflate a little to riding pressure, and go for a test ride


When is a bike frame considered too tall? I'm currently riding a road bike that feels too short for me. I use it to commute 17 miles per day.

I recently went to a bike shop, and they told me that your ideal frame height is to stand over the bike, lift up the frame, and have no more than a thumb width space below the tire. They also said the frame is measured from the pedal axle to the intersection of the seat post and the cross beam. They said a 57cm frame was probably the best fit for me.

I went home and measured my current bike and it was a few inches smaller. However, I have a few other bikes in my garage in need of repair, and I'm hoping to restore one if it's the right size for me. I measured one and found that it was an inch (~2cm) taller than my goal of a 57cm frame. I was able to stand over the bike with my feet flat on the ground (but the tires were flat).

I'm wondering if this is an acceptable height. How tall is too tall? What downsides are there when the bike becomes too tall versus too short?

You can go as tall as you like. Have you seen those tall bikes that people must climb up a ladder to use? However practicality is another thing. As the comments have said - enough room to stand-over is a good start. Try getting a bike-fit, adjusting certain geometry (saddle hight, stem etc) may help in your circumstances.


Aero wheel on front, regular on back - why? I've seen a lot of riders in the city, usually fixe riders or courriers, riding bikes with an expensive aero wheel on front and a regular, cheap-looking, un-aerodynamic alloy wheel on back.

Why would anyone do this?  The main reason I can think are that:

Ones budget is preventing one from getting another aero wheel.
It's just a style thing
There is actually some advantage to this setup

This question has a lot of relevant information and seems to point to the fact that bike handling will be much worse with this kind of setup, so I would probably eliminate the possibility of it offering some kind of advantage.

So is this just a style thing or what?

I think this is being over-thought. Aerowheels on messenger rigs have nothing to do with performance, quicker locking ability etc. etc. It’s just the new generation mimicking the older generation, trying to be cool.

When I was a messenger, many of us were pursuing racing careers.  The messenger gigs were essentially poor man’s training, and a steady source of income- since sponsors didn’t give you enough to live even on ramen. When fixies started to become cool, the next generation of messengers were mostly posers. I say that with love- spend enough time on the bike, and the most blatant, fashion-conscious poser will become an actual rider, and to their credit, that’s exactly what they did, and many of them ended up very cool people in love with the bike. But sometimes some lame things from the early part of that process can survive, and even end up being the norm.

So it was with the racer affectations such as aerowheels. A lot of those guys looked up to the older messengers, they’d see them around town on their race rigs when they weren’t working, and monkey-see-monkey-do.

I remember once I was trying out a full-carbon (no padding) saddle from a sponsor. This was bananas back in the day, because even though carbon wasn’t exactly new for frames, it was cutting-edge for this kind of application. Anyway, I ran into some young’ns down at the shop, and like two weeks later, there was a full-carbon saddle craze among the hipsters who were on the job. That saddle was horrible even with chamois- I basically tried it and sold it. I can’t imagine what it must have been like with jeans and being weighed down with fifty pounds (24 kilos) for the mail run. But they rocked ‘em, god bless those crazy kids.


Will changing from a touring bike to a racing bike improve my energy level? I'm 50 and have been cycling for years, but only 25 mile rides and indoor training. I've been training for 8 weeks, adding 5 miles a week to my big ride, but at 60 miles it is taking me 4:20 and I can't seem to improve my average!

I am on a touring bike but really seem to struggle with energy. I only eat once half way but drink regularly. At my rate 100 miles is going to take me about 7 hours. I don't think I can ride for that long.

Would a racing bike make that much difference? I am cycling about 110 miles a week currently.

I think the times you're posting for the distances you're riding, especially on a touring bike are pretty reasonable. Professional athletes, or racers, will ride quicker, but for an amateur aiming for a century your times are fine. On a longer ride, you need more time for rest stops and food and nature breaks.

A road bike will make you a little quicker, especially when you're riding into a headwind. It will also make the time spent more comfortable because you have more options to vary your position.

Make sure you keep up your fluids, electrolytes and carbs. Sports drinks, energy gels, sports bars and glucose lollies can really help when you hit the wall, or 'bonk'. On long rides, you need to keep eating regularly, even if you don't feel hungry (sometimes even when you're sick of eating sugary foods). It's amazing the pick up you can get from eating some good fuel.

Keep riding, keep training and the distance and time on the bike will be more achievable and comfortable.


Is there a measurement for tyre profile or height from rim? I have a small child road bike frame that takes 20 inch wheels. It comes with no information from the manufacturer, but from what I've learned there are two 20 inch wheel/tyre standards 406 and 451.

Based on measuring the fork, 451 wheels will fit but with very little clearance. If it were an adult road bike frame with 700/23c wheels/tyres I wouldn't be concerned but from what I've seen 20 inch tyres tend to be 'fatter' or rounder than their adult sized counterparts.

So - my question - is there a standard to define how high a tyre rises from a rim? If not, is there a calculation/rule of thumb you can use? Or even a crowdsourced resource of end users real world rim/tyre combinations?

If you look at the ETRTO specification of a tire you are thinking of using, e.g. 47-406 (a 20 x 1.9" tire) the total diameter of the mounted tire will be pretty close to the rim diameter plus twice the tire width: 406+2*47 = 500mm ~ 19.7".  (the designation 20" wheel here comes from the diameter of the common 50-406 tire).  The width of the tire will vary depending on the tread, but will be within a few millimeters of the ETRTO width.

While the most common 20" (406) tires are ~2" / 50mm wide (especially on kids bikes), it is possible to find skinny 20" tires but you need to get skinny rims to go with them.  ( Schwalbe has a chart of rim widths http://www.schwalbetires.com/tech_info/tire_dimensions).

As others have mentioned, if you have rim brakes, only one or the other of 406 or 451 will actually work for you and if it isn't a BMX frame, I would guess it is more likely to be the more common size of 406.