chain wear on a fixed?

bilsea159

Is chain wear faster on a fixed than a geared bike? I ask the question because on my geared bike the chain stretches and I replace it, and on the fixed surely I can compensate for stretch by retensioning the wheel in the dropouts? What sort of mileage is realistic before changing the chain.

meagain

I suppose someone better say SOMETHING!

First as I'm sure you know chains don't stretch -rather, as far as I understand, they wear at the holes in the side plates through which the pins pass.

On a deraileur bike slack generated by such wear is - again I'm assuming! - taken up by the rear mech. This doesn't however cure the problem! The worn chain doesn't perform as effeciently - and adversely affects the other drive components - the sprockets and the rings.

So retensioning the chain on a fixed is, as with the rear mech, simply dealing with some of the symptoms, not the problem. As to mileage....depends on more things that I can bother listing, but including quality of the chain, environment in which bike is used (wet sand will destroy the linkage very quckly - think grinding paste), the cleaning regime....

I guess that the only way to tell is the traditional method/rule of thumb as to length of 12" of used chain compared with new - and to my shame I forget how much "over length" is considered as too much! I just sort of feel the thing!

Someone enlighten us, please.

stickman

I can't remember that, I just use chain checker, mine's a Park Tools one.

JonEdwards

The above is correct up to a point. The difference is that your shifting performance won't diminish due to the worn chain and you can't get chainsuck.

So you can go on using the stuff as long as you feel happy. The chain will get rattly as the bushings wear, and eventually neither the ring nor the sprocket will be happy taking a new chain.

Me? Well I got 3 years /15000 miles out of an Izumi chain on my commuter without ever cleaning it properly (wiped it down with a rag occasionally) and used in all weathers. A track bike I "cared" about no doubt would get changed a lot more often. In the end I changed the whole lot because I wanted to run a higher gear, not from any service issue.

GarethPJ

It's a very complex subject. The pins, sideplates and rollers wear and all sorts of things accelerate the rate of wear. On a deraileur geared bike chain wear is accelerated by the fact that the chain has to flex side to side in different gears. On a fixed wheel bike wear would be accelerated by the fact that the chain is under tension whenever you're moving.

In theory smaller rings and sprockets will accelerate wear, the pivots have to move more to get round a smaller ring or sprocket. And smaller rings/sprockets will wear faster because each tooth is seing more action per mile. Theoretically running a 1/8" chain on 3/32" sprockets will also theorectically accelerate wear since the chain will flex side to side a little as it is a looser fit on the sprockets. On fixed if your chain line is out that should accelerate wear.

I've even heard a theory that running a ring with an odd number of teeth and a sprocket with an even number will reduce wear in both chain and sprockets because any tight or loose spots in the chain will not always hit the same tooth and any irrecularities in the ring/sprocket will not always hit the same link. I think this is probably nonesense since good quality well maintained chains should have any tight or loose spots and good quality rings won't have any irregularities.

So if you believe all the theories to minimise chain wear you need to run single speed freewheel with a spot on chainline and the biggest ring and sprocket you can find, with a 1/8" chain on 1/8" rings with an odd number of sprockets on the ring and an even number on the sprocket . Which doesn't sound very realisitic to me.

However in the real world away for theories the largest influence on the rate your chain will wear is the quality of the chain itself. Cheap chains, in general, will wear more quickly than expensive ones.

One caveat however, I have heard tell that some expensive track specific chains are very low friction but are not well sealed against the elements so will wear quickly if subject to our climate. That being the case an expensive BMX or MTB chain might be better.