shifting problem

[coopdog]

I need some help. I replaced my 12-25 mirage cassette with a new 11-23 chorus cassette and chain. The bike shifts fine down the cassette, but it will not shift up well. It either hesitates to shift or it will jump a cog. If I try to adjust it out, I mess up the down shifting. The derailleur cage looks straight to me.

Thoughts?

[regularguy412]

No new chain with the cassette replacement?

Additionally, lubing the cable and housing will likely help. In fact, replacing the cable and housing may be the only thing that really fixes it. This assumes the der has been fine-tuned properly.

Mike in AR :beer:

[Ken Robb]

when he says it doesn't shift well up the cassette I'm imagining that he means onto bigger cogs which would be under tension not spring pressure. My grungiest cables have always shifted fine when I was pulling cable even though they were to dirty/sticky to shift well under spring tension going to cogs smaller in size.

[CaptStash]

a thought: (since you asked) Start from scratch. download the rear derailleur tech. manual from Campy and follow their directions from start to finish on tuning. If that doesn't solve the problem, then (and imho only then) start looking for a mechanical problem.

CaptStash....

[thinpin]

Are you following the recommended installation proceedure?
With the chain off (its eassier this way) are the jockey wheels exactly below the forth smallest cog when the shifter is set for that position? Adjust the tension using the sping tensioner on the Der to do this. Pop the chain on and resume shifting. If the shift to a larger cog jumps then the cable is a little too tight -slacken off a 1/4 turn at a time. This should stop the"down shift" becoming a problem.
If this does not get a result then I suspect the cables and sheaths are banjacksed and need replacing.
What Im not sure about is if is there compatibility issues with your shifters/der/Cassette. What are you running?

[coopdog]

It is all 2007 campy mirage 10sp with about 5k miles. The replacement parts are a new 10sp chorus cassette and new wipperman chain. It was shifting fine with the old cassette and chain, so I'm pretty sure it is not the shifters, and I just replaced the cables a month ago.

I'll try taking the chain off and starting on the 4th cog like you said. Thanks.

[Birddog]

Which Wipperman chain. They made an older version 10 speed chain that was/is wider than Campy's Ultra Narrow version. This might be part of the problem. I had a Wipperman early version 10 speed chain and it worked OK, but was noisy. When I switched over to the Ultra Narrow Campy, it worked much better and was far more quiet.

Birddog