Bicycle Mechanics - gears slipping

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RVD72
10-21-09, 12:06 AM
Hi,

My bike has Ultegra components and low gears slip when climbing. I'm not sure of the exact teeth but I'd say that teeth 2-4 (going from low to high gear) on the rear cassette slip. It sometimes slips on flats but it's definitely noticeable when climbing. It's to the point where I'm either on gear 1 or gear 5 to avoid the gears slipping.

I thought it might be a bad cassette but the old cassette was only about 4 months old. I bought a new cassette anyway but it's still slipping at the same place. I suppose it could be the chain but the chain is only 6 months ago.

I did remove the rear cassette to install it on a new set of wheels. Is it possible for me to have messed up the teeth with the chain whip when I was removing / installing the rear cassette?


Thanks.
Rock.

msummers
10-21-09, 12:11 AM
I would think that it likely has to do with pulley alignment or cable tension IF you're sure your chain isn't worn. (Usually this is a fault of your chain if you frequently change gears while hammering)

If you have realigned the derailleur and reset the tension and your gears still slip, I would take it to an LBS so they can tell you if something is bent in the derailleur or on your hanger.
operator
10-21-09, 01:08 AM
Hi,

My bike has Ultegra components and low gears slip when climbing. I'm not sure of the exact teeth but I'd say that teeth 2-4 (going from low to high gear) on the rear cassette slip. It sometimes slips on flats but it's definitely noticeable when climbing. It's to the point where I'm either on gear 1 or gear 5 to avoid the gears slipping.

I thought it might be a bad cassette but the old cassette was only about 4 months old. I bought a new cassette anyway but it's still slipping at the same place. I suppose it could be the chain but the chain is only 6 months ago.

I did remove the rear cassette to install it on a new set of wheels. Is it possible for me to have messed up the teeth with the chain whip when I was removing / installing the rear cassette?


Thanks.
Rock.

http://www.parktool.com/repair/readhowto.asp?id=64

Check/test for twisted/frozen link. Then start thinking about replacing the chain/cassette. It is entirely possible to wear a chain out in 6 months.

dperreno
10-21-09, 09:30 AM
I would bet it's your chain - you may have a link or two that are slightly bent or stiff. I had similar problems with a chain that I had "dropped" off of the small chainring earlier this year. Turns out I had just slightly bent a couple of links. I replaced the chain and my problems were solved!