|Anyone ever twist a chain during a ride?||commuterguy|
Jul 8, 2002 8:49 AM
|20 miles into a hilly ride yesterday, I shifted to the small chain ring and then felt the cranks lock up. I look down, and the chain is on the BB, so I coast to the side of the road and investigate.
It turns out the cranks won't turn because several links in my fairly new Ultegra chain are twisted, and have become jammed in the rear derailleur. I was fortunately riding with an experienced friend and carrying a chain tool (part of a multi-tool). We removed three links, reattached the chain and limped back to the car.
I can see no damage to the chain rings, cassette or rear derailleur. I don't know how the chain got bent--I assume it would take a lot of force to twist it so much (at least 30 degrees). I was actually able to use about 6 of my 9 cogs on the return trip (a good thing too, for anyone familiar with Park Mills Road in Frederick Co., MD).
Prior to this mishap, I had gone up some very steep hills (granny gear, out of saddle, working very hard, and managing 7-8 mph). But I crested the last hill and had gone at least 0.5 miles without incident, so the chain and RD were still getting along OK. The only other thing out of the ordinary beforehand was an uncharacteristic two-stage FD shifting: in going from the big to small ring, it took two "snaps"; if I didn't move the lever far enough I would hear the first snap, the FD would move a little, but it wouldn't move the chain. Only after a second try (and "snap") would the chain move.
Finally, I wasn't pedalling hard when I shifted, and I had recently cleaned the chain and not noticed anything out of the ordinary.
Any ideas regarding what might have happened?
|happend to me||ishmael|
Jul 8, 2002 8:53 AM
|Im pretty sure the chain got stuck between the chainring and the chainstay, I cant imagine anywhere else that much force could be put on the chain. I coasted to the nearest pizza store and borrowed a wrench and bent it back. Worked fine for months.|
|re: Anyone ever twist a chain during a ride?||pa rider|
Jul 8, 2002 9:18 AM
|I've done it twice a few years back. I dropped the chain and mashed it into the bottom bracket area. Each time I bent one was because of bad shifting.
I had to put a new chain on each time. I haven't drop a chain much over the years. Plus I learned that taking the time to get off the bike and put the chain on may save problems from happening (bending the chain links).
I only did this to shimano chains, so I switch to SACH road chains back then (this was 1995). I liked to be able to add links if I bent any, which you can't do with the shimano, without the special pin. I use an Ultegra now, but make sure I don't jam the chain if I drop it.
By having my front derailer limit screws adjusted helped me from overshifting when dropping to small chainring. Hope your chain wasn't too old and a new one works with your drivetrain (cassette and chainrings) to keep your cost down.
|I have done it too||LC|
Jul 8, 2002 9:53 AM
|It was from chain-suck, which is where the chain sticks to the chainring and then wraps over itself. Usually happens on mountain bikes riding in mud, occasionally it can happen on road bikes too. The cause is usually dirty/poor lubed chain or worn chainrings.|
|I've made a knot in a chain once....||MrCrud|
Jul 8, 2002 10:15 AM
|.....no clue how i pulled it off though! Kept the chain as a trophy for awhile!!! I never shift in front while under full throttle anymore....
|Re: I've made a knot in a chain once....||commuterguy|
Jul 8, 2002 11:52 AM
|Thanks for your collective input. I just returned from an LBS, where I got a new chain and cassette (SRAM PC-89 and Ultegra, respectively). They weren't surprised at my problem: big ring-big cog and/or small ring-small cog gear combinations, and shifting without feathering the pedals were the likely causes, they said. I think I've gotten careless about he latter, but generally don't do the former.
This was the second Ultegra chain I've gone through in 4100 miles. I hope the SRAM lasts longer--at least I can keep it cleaner more easily by taking it off the bike. Why doesn't Shimano develop a power link-type chain?
|Not uncommon in singlespeeding or fixed gear ...||Humma Hah|
Jul 8, 2002 1:30 PM
|... singlespeeds and fixies have no chain slack, so if the chain comes off and jams on the chainring with sufficient force, it may twist.
To happen on the small chainring of a der blows my mind.
I can see it could happen with badly crossed-up gearing, big ring and big cog in the rear, eating up all the slack. Probably would twang the rear der, too.
My best guess is you experienced "chainsuck", which, due to a lot of slack available, doubled-up the chain and led to a major jam.