anyone know about chain wear?
ris
Posts: 1,002
in General Chat
i bunged my less than year old bike in for a quick service today to the shop where i bought it. it doesn't need anything doing particularly, although the bottom bracket (or something else, perhaps) is creaking when i put a lot of load through it.
been told by the shop that the chain is over stretched and i should replace the chain and cassette. i told them i'd sort it out myself.
i swapped the chain out in march and put a new kmc 9spd on it. it went on fine and had no skipping issues. i've kept the old chain cleaned up and was going to swap it back on after bath OD next week. the new one has been regularly cleaned and lightly lubed and maybe covered 1000miles, which is a bit longer than i'd like before swapping back but there you are.
doesn't feel right... either that kmc chain is complete rubbish (i'll find out when i check it myself, i hadn't done so for a bit) or they were trying to pull a fast one. i'd have expected the chain to last more than 1000 miles, and i suspect the cassette is fine but they figure it's easier to assume it's gone.
anyone got any experience with chain wear?
been told by the shop that the chain is over stretched and i should replace the chain and cassette. i told them i'd sort it out myself.
i swapped the chain out in march and put a new kmc 9spd on it. it went on fine and had no skipping issues. i've kept the old chain cleaned up and was going to swap it back on after bath OD next week. the new one has been regularly cleaned and lightly lubed and maybe covered 1000miles, which is a bit longer than i'd like before swapping back but there you are.
doesn't feel right... either that kmc chain is complete rubbish (i'll find out when i check it myself, i hadn't done so for a bit) or they were trying to pull a fast one. i'd have expected the chain to last more than 1000 miles, and i suspect the cassette is fine but they figure it's easier to assume it's gone.
anyone got any experience with chain wear?
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Comments
Try measuring the chain - that will tell you for sure if it's stretched. Might be an obvious question, but do you ride a lot on the small chainring and the smaller cogs at the rear? That's the fastest way to wear your chain out...
http://www.sheldonbrown.com/chains.html
When you changed your cassette did you calculate the chain length?
http://sheldonbrown.com/derailer-adjustment.html#chain
zacnici - when i put the the chain on i measured once, twice, thrice and then a couple of more times before i cut it to length. doesn't mean it was right though!
nivagh - i tend to ride on the larger front chainring (50) most of the time, and on my usual commute i will get across the full range on the back more than once. i probably spend most time in the middle-lowest cogs so it could be contributing to the wear. i do ride with a pretty high cadence and i'm not a heavy rider (maybe 70kg), but i'm not sure what difference that makes.
at the end of the day if the chain is stretched then it's stretched, i'd have hoped it would get through more than 1000 miles though. i hope the cassette is ok!
Chain life varies all over the map, with the major wear factors being:
#1: Your weight and style of riding. Heavier and/or stronger rider=greater chain wear. Kinda obvious. A 105 pound woman can get remarkably long chain life compared to a 240 pound guy. Nothing sexist here...you can reverse the numbers if you wish.
#2: A clean chain is a happy chain. Those who regularly keep their chains clean (not just the outside, but the interior bushings, where the real wear occurs) get much longer life than those who don't.
#3: Terrain. A BIG factor. My guess is that those who climb a lot probably get one-half the life out of a chain that someone in Nebraska gets.
#4: Chainstay length. Very short tri-bikes (those with 650c wheels) tear through chains very quickly. This is actually a function of two different things. First, the shorter chainstays mean the chain is frequently bending/twisting at a nastier angle than on a bike with longer chainstays. Second, the smaller wheels mean you have to use smaller rear cogs to achieve the same speed, and this accelerates both cog and chain wear.
All of these wear factors are cumulative, so it's possible to wear a chain out *really* fast, or have one last *really* long, given the right (or wrong) mix of wear factors. I should also point out that mountain bikes can wear through chains in as little as 300 miles under "normal" use. This can occur even with regular cleaning, since a mountain bike chain gets so dirty so fast that it operates most of its life under less-than-ideal conditions! Obviously, the type of dirt you ride through has a major effect on the wear rate as well...kinda like how grittier sandpaper works a lot faster than fine sandpaper if you're trying to remove paint.