rohmen

Hi all. I was hit by a car three weeks ago and have had problems getting my drive train working properly ever since. Had problems with chain skip immediatley after the accident. The chain would skip roughly but would not autoshift to a different gear. I replaced the cassette and chain on LBS's advice since they were both pretty worn. I also had a LBS straighten my derailleur hanger and professionally tune my RD. After all of that, large skips have gone away but the chain still seems to catch or slip slightly when it comes off of the cassette ring and onto the top pulley of the RD. Problem is the most noticeable when I am in the middle of my cassette and in my largest chain ring. I am using a Shimano STX front and rear derailleur. My new cassette and chain are both SRAM. I replaced the chain myself, so I guess I could have damaged it when I shortened it (I used a good chain tool, but I'm not an expert by any means). Any one have a guess as to what is wrong and how to fix it??? Thanks.

Steviek216

Hi Rohmen. I had an accident about 3 months ago and was also suffering from chain slip/skip/and fall. My LBS also took a look at my bike and came up with that I bent my chain ring. This was not true, but it was the solution that they came up with. My solution was that I bent my bottom bracket, also not true but I ended up with a sweet bottom bracket so no worries. After both obvious solutions had not solved the problem I brought my bike to yet another LBS who came up with the correct solution of that my frame had been bent. I would imagine that this might be the problem. Check to see if it is one place in the rotation that the slipping occurs. If so, your entire bike may be out of alignment. Just a thought.

tellyho

I would also take a look at your derailleur hanger.

rohmen

Thanks for the suggestion. The very slight slipping occurs now with almost every peddle stroke, not just once every full rotation of the chain. For lack of a better term, the chain is basically always kludgy when it is coming off of the cassette onto the first RD pulley. Does this rule out a bent frame?

They did straighten the RD hanger, but maybe it is still out of whack.

JiveTurkey

Is the derailleur hanger replaceable? If not, is it steel or aluminum?

I crashed my MTB and bent the derailleur hanger. I striaghtened it myself, but found that it would not quite stay true. One day, the bike fell over on its right side in my kitchen. The aluminum hanger was so weak that that little fall totally made the hanger out of whack again, so I replaced it.

Recheck the hanger (or at least eyeball the derailleur cage and see if it is still paralll to the cogs).

kmo7882

Another thing that may cause this is a stiff link in your chain. Off the bike, rotate your pedals backwards, and carefully watch your derailleur. If it jumps in the same spot on the chain, then check the link. It may be stuck from where you put it back together. The pin / link just needs to be "worked" to loosen it up.