madmaxone

I have a 2009 Trek Madone 4.5 with 4000 miles on it. Bike is stock with 10 speed shifters 105 STI, 105 double crankset, Ultegra RD, 105 10 speed cassette (11-25) and (now) an Ultegra chain.

My problem started when my chain would slip off of the cassette, only in the middle gears 5 and 6. I took it to the shop and they put on a new Ultegra chain, adjusted RD and I rode off no problem. 30 miles later same skipping problem, same gears.

I went back and they re-adjusted RD and lubed shifter cable at the lever. Approximately 30 miles later, same problem.

Back at the LBS they found a frayed shifter cable after test riding it, so they replaced that, lube, adjust RD etc. All good until about 40 miles later. Same problem in the same gears.

Any suggestions? I like this shop and the guys are cool, and I like to support them. I also would like to expand my mechanical knowledge and not have to rely on only them. Should I try a new cassette or do you think something might be stripped?

Thanks in advance.

fietsbob

replace the chain and cassette at the same time, you only replaced the chain,
as I read.

you probably delayed the chain replacement too long, to not replace both..

Looigi

Yeah. If a new chain is jumping on the cassette, the cassette is very likely worn out.

A worn out chain will accelerate cassette wear. Replacing the chain at reasonable intervals will help extend the life of the cassette. Of course chains cost money and cassettes cost money, so you kinda gotta do the math to figure out what's the least costly strategy.

Lawrence08648

I agree, probably a cassette though I replace my cassette every two or three chains and more mileage than 4,000 miles. Those gears may be the ones you use the most so they are the most worn but it also could be a bad cable housing, inside the housing. If you didn't have the housing replaced at the same time, then have the housing replaced. The housing needs to be lined, plastic, teflon.

FBinNY 

If you're describing the chain slipping (skipping) over the top of the teeth under load, it's classic for a worn cassette. If you were on the original chain for 3 years, the chain would have worn and likewise worn the sprockets you used the most. It would have been nice to have the original chain to measure for wear (stretch) as confirmation, but it's so classic we can probably do without it.

Replace the cassette and you should be fine (save the original in case this isn't the issue).

BTW- chains and cassettes wear together. That's why riders monitor chain wear (stretch) and replace the chains before the cassette is so worn that it won't run with a new chain. The fact that your old chain was already skipping is fairly clear evidence of wear beyond the point of no return, and any decent mechanic would have measured the chain to confirm, then warned you that it was likely that you'd need a new cassette also.

madmaxone

Thanks alot for the advice. I actually suggested a new cassette when I purchased the chain, but the LBS said it was fine. I'm picking up an Ultegra cassettte tomorrow and I'll let you know how it works out.

ThermionicScott 

Pics of the cassette would help.

madmaxone

Its all good now with the new cassette, thanks everyone.