Chain keeps falling off
 

My chain keeps falling of during races, usually when I'm putting my bike down. Anything I can do to keep it on? I'd like to keep my large chain ring, since I also commute on the bike. Should I shorten the chain for cross races?

Make sure you set your bike down gently. Tough to remember in the middle of a race, but worth it. I got lazy at a couple races in the beginning of the season and dropped the bike (and chain), but a conscientious effort has fixed the problem.

Shortening the chain may help too.

Are you consistently losing it on one side? Which side?

yes. turn the limit screw a bit to tighten up the gap. (if that doesn't make sense, take it to a shop). that should help, i assume. maybe the derailleur is also too high? take a few pictures and post them. one looking at the crank, and the other one with the chain in the big ring from the top down. that'll help.

You could also install a chain keeper like Third Eye or the like to keep the chain from falling off to the inside of the small ring. I dropped my chain twice during my first season. After installing a Third Eye and getting better at gently putting the bike down vs. dropping, I've never dropped it again in the 25+ races since.

It always falls off of the inside of the small chain ring. I think it is falling off of the bottom of the chain ring first, as once, when i went to pick up my bike, I noticed than the chain was off the bottom, but still on a few teeth on the top, so I pushed the crank with my hand as I was shouldering the bike and I got the chain back on. I'll post photos when I get home.

well then i'm totally wrong. but it could be that same problem on the inside. try a 3rd eye (i use an N-stop gear jump thing.). that should fix it

+1

Don't drop your bike.

i put my third eye back on. but also i swapped out my mid cage rd which i did not need for a short cage rd, which allowed me to shorten my chain up by 5 or 6 links. being more gentle when setting the bike down has also helped.

Reviving this old thread after a search - I'm having the same problem as the OP. My chain is constantly (2-3 times per race) falling off to the inside, and it's driving me nuts. My setup is:

1x9 - 36t in front, 11-25 in back
Ultegra Short Cage Rear Der
N-Gear Jump Stop chain keeper

I've experimented with the Jump Stop's adjustment quite a bit, but it's still not doing the job. At my last race, the chain fell off to the inside and jammed under the Jump Stop so badly that it took the better part of two minutes to get it back on, costing me at least 30 places or so. In my haste to get the chain back on, I moved the Jump Stop so that it rubbed loudly when in the top two or three cogs. Two laps later, crossing a set of barriers I lightly grazed the second barrier with my rear wheel and it went off again to the inside. Luckily I was able to quickly replace it.

What could I be doing wrong? I've already tried shortening the chain by two links, should i shorten it more? Those of you who use those plastic chain keepers, do you have this same problem?

I thought the Jump Stop was designed so your chain can't fall off to the inside? With a single chain ring in front it would make sense if it fell off to the outside because you aren't running a chain guard. Are you dropping the bike too hard? 2-3 times per race is unexceptionable and I hope you figure this out.

For $52 you can get a Paul's chain keeper and the problem is solved.

Yeah - you're telling me! I've been having great races lately except for dropping the chain. It's incredibly frustrating. I'm definitely conscious of dropping the bike too hard, and feel that in general I'm pretty gentle with it - after watching rider after rider losing their chain by dropping their bike too hard at the top of a steep runup a while back, I vowed to avoid it at all costs.

I know that's the idea with the Jump Stop - it's just not working for me. I'm going to try again, moving it as close as possible to the chain while it's on the largest cog and dealing with the small amount of rub noise, but I'm not confident that it's going to work.

Forgot to mention that I am using a chain guard, and losing the chain to the outside has never been a problem.

your chain length should be such that your derailleur pulleys line up with each other, and are perp to the ground when in your smallest cog.

Ok - good advice there, I think my chain is a bit longer than that. I'll check that out.

Run a bash ring on the inside and outside. I'm pretty sure that will end the chain dropping.

Bash rings are the best solution but a FD works just as well too. Just get an old junker front derailleur and fix it on there. You can even bend the cages if necessary for cross chain rub.

Chain Length Sizing

http://parktool.com/images_inc/repai.../chain-OK1.gif

Problem solved - too much chain. Shortened it by 3 links, no more chain drop. Thanks!