I am a super newbie to racing and did my second race ever this past weekend. I did reasonably well all things considered, but I dropped my chain several times. The course was REALLY bumpy so I figured that may have been a factor, but I am wondering if there is some other cause, i.e. technique or a chain issue. It was always on the small ring and always to the inside, though couldn't tell you where on the cassette i was when it was happening. The chain is only about a year old, so I wouldn't think it would be totally stretched out.

I did not have this problem at my first race, so I would appreciate any insight on how to prevent this in the future.

Get some kind of chain deflector like the N-Gear Jump Stop. I run those on my cross bike and my 1x9 MTB. Cost about $15 each and well worth it.

On bumpy terrain try pushing a bigger gear. The gear "pushing back" at you a little will help your legs absorb the bumps, and if you can get the hang of it you can keep applying power through the bumps which will keep the chain tight. That might help with the dropping too.

A chain deflector will definitely help (and will probably fix the problem completely). You might also want to make sure your chain isn't too long. I'm probably at the ridiculous end of this, but I keep my chain as short as I can get away with so that there's less to bounce. I use a 1x10 setup, and with the chain on the big cog my setup looks like this:



Obviously if you're running a 50-34 crank you need a lot more slack than that on the small ring. A 46-36 crank will let you shorten the chain a bit.

Install a chain keeper. There are several on the market. A chain can drop unexpectedly, even with finely adjusted derailleurs and a smooth road (just ask Andy Schleck).

I use one made by Token on my road bikes.

Where on the course does this happen? Is it while you are pedaling? Then use a device noted above. If after dismounts and remounts? Then learn to set you bike down not drop it before remounts.

I'm not a racer, but I shift my 2X10 while riding bumpy terrain, and have predictably dropped chains while doing so. Next to a mal-adjusted low limit screw, and shifting the front & rear simultaneously, low rear derailleur cage tension has been the next major cause of chain drop for me. I tried minimum chain length as mentioned above, but the lowest gear shift was slightly crunchy (for those wanting to jump me about the B-screw, I know how to use it). The upper guide pulley on most road derailleurs rotates on a central axis, so it doesn't cam out of the way when the cage is hyper-extended. I have a SRAM Type2 rear derailleur now and it has eliminated dropped chains; the cage lock is ultra-useful too. The cage has a clutch which stabilizes chain tension. Shimano has a rear derailleur model with a clutch also. I see no reason why this type of drailleur wouldn't be useful in cyclocross racing if cable routing will allow.

Thanks for this thread and replies!

I've had the same issues myself on both my road and CX bikes. I started in the second row in my first CX race, started fine and was in the top 10, and then dropped my chain within 3 minutes. Finished 20th. Boo.

So I was looking at the K-Edge because that's the one I'd heard of. Ridiculous pricing. The Token and N-Gear look much more reasonable.

Token
https://www.chainreactioncycles.com/M...?ModelID=58049
N-Gear
https://www.jensonusa.com/N-Gear-Jump-Stop-Chain-Guide

Thanks guys. I think Cynikal hit it on the head as far as dropping my bike back to the ground prior to remounts. I know at least twice where that was the culprit, often combined with sharp descents as I was remounting, likely compounding the problem. I was definitely getting bounced around on that course, in addition to my not so graceful newbie remounts.

Anyhoo practice makes perfect so I'll sort it out. Getting one of those chain deflectors would probably be a smart move anyway.

You want to put the bike down not drop it. What I do is to make sure the bike is on the ground and I take a couple of steps before remounting.

Yep. Setting the bike down smoothly and gently is critical. In addition to the chain thing you don't want to be trying to remount an unstable/bouncing bike.

Just stay in the big ring. Problem solved.

P.S. 50/34 is crap for road, but especially for cross. 42/34 or 46/36 = perfect. You can take up a lot of slack with a shorter chain.

Oh, tighten your inner limit screw, too. Even if it rubs a little when you're in the biggest cog.

Looking at Werkin's picture made me think another way to be able to shorten your chain is to use a smaller cassette. A 32T cog makes you slow, and a 12-25 cassette requires less chain. Those extra links also save you a couple of grams, if your the weight weenie sort.

Of course, the best way to get a short chain is to go single speed. Not a lot of chain slap there.

Yea I am running a 50/34 and while fine for road riding, definitely not ideal for cross. It being my first season and really only owning (or even have space for) one bike, it does double duty. But I think I will be investing in at least a new set of chain rings and pairing them with a shorter chain. I also like the idea of running a 1x10 setup but would probably need a dedicated race bike for that.

I didn't use my big ring at all in this last race and even in my first race I only used it for the start. After I got onto the dirt it was never used again. Still figuring out a lot of stuff and proper gearing is one of them. Mostly just going with the, dive in and figure it out technique, but I know I am doing at least 3 more races this season so plenty of time to learn.