HELP: Chain always stuck between granny and bb...

last night I was riding around my local county park and in the midst of downshifting on a hill climb I threw the chain off granny gear. As usual it got lodged between the bb and granny, but this time it got stuck HARD. I was wrestling with it for several minutes on the trail before it finally loosened up enough for me to reset it (DMZ you recall this happened at six mile run a while back too). This happens to me often enough to be more than a minor problem.

I noticed that the links were showing a lot of wear from the friction of fighting it out of the gap between the bb and the little ring. Has anyone else had to deal with this, and if so, what was your solution? I was concerned that I was going to break the chain, or cause so much wear that the chain was going to be worthless for the remainder of my ride. Luckily I was able to finish the ride and the bike seems to be OK, but I am afraid this problem will continue. It happened to me at CR a few weeks ago and is likely to continue to be an issue...

any advice as to what I can do? I know if I change the bb to a smaller width I will also alter the chain line, which means - what exactly? I will have to get new rings and cogs too? I cannot afford that right now so I need a cheap and easy fix for this problem.

thanks ~ Jig
 

ytc100

New Member
Were you down shifting from middle ring to small? I've had this happen in the past when my front dérailleur wasn't aligned correctly - always takes me a bit of experimentation to get it just right. I've also had chain suck issues when shifting from middle to granny under tension which has lodged the chain between granny and frame nice and tight. New rings and better shifting technique solved that one for me.
 
Were you down shifting from middle ring to small? I've had this happen in the past when my front dérailleur wasn't aligned correctly - always takes me a bit of experimentation to get it just right. I've also had chain suck issues when shifting from middle to granny under tension which has lodged the chain between granny and frame nice and tight. New rings and better shifting technique solved that one for me.

maybe it is shifting technique that is lacking...i have new rings, less than a year on them. The front derailleur has been having issues from middle to granny and I think that may be the place from where this problem stems. Once I get the cable tension corrected I might not have an issue. I will work on it this weekend, hopefully a solution will present itself. Thanks. :)
 

anrothar

entirely thrilled
it could probably be corrected with a derailler adjustment. when it does fall in between there though, it will likely get stuck hard. key for removing it is to be really gentle and just sort of lightly wiggle it out. they used to make this device that was sort of like a little thumb that stuck out from your seat tube below the front derailler. it lined up just below the top of the granny ring, and prevented the chain from falling all the way to the bb. might still be available.

if i remember correctly, trouble shifting from middle to granny, and chain jumping off of granny when downshifting into it, typically means the derailler is a little too high, is crooked and/or the cage is bent.
 

Shaggz

A strong 7
definitely check the alignment. the fd is more difficult to adjust then the rear. so you may want to bring it into the lbs with a six pack and offer to break down some card boxes as a bribe to learn the tricks. also, try backing off on the power when downshifiting.
 
Soundz like...

The derailluer is adjusted abit past granny. Turn the philips screw marked L in a smidge (1/8th or so). Better yet download the instructions from the Shimano or Park tool site and pretty soon you'll be a pro. Definitely will be time well spent.
 
The derailluer is adjusted abit past granny. Turn the philips screw marked L in a smidge (1/8th or so). Better yet download the instructions from the Shimano or Park tool site and pretty soon you'll be a pro. Definitely will be time well spent.

thanks, we are working on it. FD does not appear to be bent but it is out of alignment. Also, the cable tension is whacky. Now that I can put the bike up on the stand vs. trying to wrestle with it on trail I can see how far past granny it was when in the lowest position.

might be time for new cables and chain, too. Does it ever end? I feel like I spend more time doing maintenance on my bike than on my car...
 

Norm

Mayor McCheese
Team MTBNJ Halter's
Do you ride your car on rocks, roots, logs, and though streams?

Oh and no it never ends.
 
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Do you ride your car on rocks, roots, logs, and though streams?

I was going to make a vapid attempt at a humorous response, but it would have been all vapid and devoid of humor.

Norm, I see your point. And since I provide the power for the bike, I tend to notice more when things are not in good order and have to be fixed. It's teaching me a lot (sometimes the hard way) but I am glad to have this particular skillset.
 

PedalPaddles

New Member
So far, all good advice. I would add that a clean drive train always has fewer problems and shifts better than a dirty one. I would start by turning the Low limit screw an 1/8 of a turn like he said. One change at a time and keeping it clean.

As far as technique is concerned, you do not want to shift under heavy load while climbing. You can shift while climbing if you do this...surge by pedaling harder for a crank or two, then shift while easing up on the pedal pressure right afterwards. This creates a 1 or 2 second "coast" that reduces the tension on the chain and allows it to move to the other ring more easily.
 
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