I recently installed a Shimano 105 12 - 25 cassette (previous was 12 - 23) and now the chain is skipping regularly when I'm out of the saddle climbing in the 39 - 17. It only happens in this combination (when it does, I will shift one way or the other and don't have any problems). I don't think the gear is too high for the climb as I'm not applying that much pressure to the pedals when it skips.
I had a new chain put on the bike back in March when I had it overhauled and it's been ridden 5 - 600 miles since (both commuting and workouts). With the exception of the new cassette, everything else is Ultegra.
Any suggestions would be greatly appreciated as it's causing a crisis of confidence when I'm climbing (need to make sure if I stand up that I'm not in that gear).
I had same problem on my MTB when I replaced the cassette towards the end of the season. I had replaced the cassette and first ride out had skipping issues under climbing loads or hard efforts at low RPMs all while in the "middle gears", like the 17 on your ultegra cassette. I replaced my chain and the skip disappeared. The explanation I got was that a cassette and chain wear together. The new cassette does not have the same wear patterns as the old one , therefore the chain and cassette no longer match up like lock and key. 500-600 miles is resonable to see this difference in wear esp. if you ride in grimy conditions, commuting etc...
The other thing to check is that the cassette is seated properly on hub and tightened into place properly.
"craig bryant" <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
I recently installed a Shimano 105 12 - 25 cassette (previous was 12 - 23) and now the chain is skipping regularly when I'm out of the saddle climbing in the 39 - 17. It only happens in this combination (when it does, I will shift one way or the other and don't have any problems). I don't think the gear is too high for the climb as I'm not applying that much pressure to the pedals when it skips.
I had a new chain put on the bike back in March when I had it overhauled and it's been ridden 5 - 600 miles since (both commuting and workouts). With the exception of the new cassette, everything else is Ultegra.
Any suggestions would be greatly appreciated as it's causing a crisis of confidence when I'm climbing (need to make sure if I stand up that I'm not in that gear).
Originally posted by Craig Bryant I recently installed a Shimano 105 12 - 25 cassette (previous was 12 - 23) and now the chain is skipping regularly when I'm out of the saddle climbing in the 39 - 17. It only happens in this combination (when it does, I will shift one way or the other and don't have any problems). I don't think the gear is too high for the climb as I'm not applying that much pressure to the pedals when it skips.
I had a new chain put on the bike back in March when I had it overhauled and it's been ridden 5 - 600 miles since (both commuting and workouts). With the exception of the new cassette, everything else is Ultegra.
Any suggestions would be greatly appreciated as it's causing a crisis of confidence when I'm climbing (need to make sure if I stand up that I'm not in that gear).
Thanks in advance.
Craig Bryant
I think Philip Golden is on the right track. Also take a close look at the spacing on the cassette and make sure that they are all spaced the same and that all the teeth on the new cassette are shaped properly. If the spacing is consistent and the teeth look clean I would check chain wear and replace if appropriate.
