I recently made the switch to a compact crank but didn't change my cassette (13x26). As you might have guessed, I've lost a bit on the low end but gained a great deal on the high end. I should state that I'm not a great climber so I need all the help that I can get.

Now I've got a problem of spinning out on the local group ride sprints. I usually have a good jump but my buddies are now regularly taking the sprints while I'm spinning out. So, I bought a campy 11x23 cassette and took the bike out last night. MAN! Now, I'm affraid I'll be walking my bike up my local climbs or blowing out my reconstructed knee.

Question - is there any way that I can take the larger cogs from my 13x26 and replace the ones on the 11x23 cassette? Will the shifting be impacted significantly? let me know your thoughts.

Thanks!

I imagine you can do this...At one point I wanted to do the same mix but with 25 cog at the end. In the end I decided against it as I saw by markings on the cogs that they would be slightly misalligned...Give it a shot and see how it works...

...Question - is there any way that I can take the larger cogs from my 13x26 and replace the ones on the 11x23 cassette? Will the shifting be impacted significantly? let me know your thoughts...

We mix and match in our house on a somewhat frequent basis. Never noticed any impact on shifting caused by misaligned ramping. If you were going to have any problems in would only be between the cogs that were from different cassettes. The top half and the bottom half of the cassette would shift as designed. The only thing to watch is depending on how the cassettes are riveted together and also be sure the spacers are properly placed. I would think you might go with the following from each cassette to get your all purpose cassette:

11-12-13-14-15--17--19-21-23-26

Veloce cassettes offer a bit more flexibility as most cogs are single.

My current practice is to replace the 23-25 in a 12-25 with the 23-26.

It would be easy also to pop the 11-15 from your 11-23 and put it onto the 17(no 18)-26 from your 13-26.

As for shift quality, I haven't noticed a change and am using ultra narrow chains.

I make my own Veloce 12-26, which I find great for training. As an above poster mentioned, the loose cogs on Veloce cassettes make this easier.

With a 13 and compact gearing you should be able to hit 35 mph without too much trouble. If you can't, you should work on your spin.

You didn't mention the component level of your cassette. Unless the cassette is a Veloce model, at least one pair and perhaps three pairs are joined on a single carrier, and can't be swapped. See pages 81-83 of the PDF: http://www.campagnolo.com/pdf/spares07_B.pdf

Your mistake was making too big of a change. Rather than moving up one cog on the top end you moved up two. On the low end, you only lost one cog, the 26T, but the jump from a 23-26 is a rather large 13%, compared to the more common 8-9% difference between cogs. You also lost the 18T which makes a very small jump between the 17 and 19.

FWIW, if you have a 34T little ring, your 34/23 low gear is not much different than a 39/26.

If you would have chosen a 12-25, then your lowest gear would be like a 39/29 and you top gear would be just a bit higher than 53/13.

If the 11-23 has little use, I'd sell it and buy a 12-25.

You're right. The jump was too large. The cassettes are both Chorus level. I may mix and match to see if I can find a combo that will work.

There really are no cogs that can be exchanged. You don't have a 12T first position cog, and you can't exchange the last two cogs either. If you take the last two cogs from the 13-26, you'd end up with a 17-19-23-26. That would be a lousy setup.

http://www.branfordbike.com/cgi-bin/perlshop/perlshop.cgi?ACTION=push&thispage=cassette/cog4.html&ORDER_ID=277154072