Southern California - Cassette

I have a spare wheel I am going to use on my trainer but my problem is I need a 9 speed 12-27 cassette for it to match my gearing on my riding wheels.

Now It can be used in good shape, and a 105 or Ultegra is fine.... If you want a 9 speed 12-23 Dura Ace cassette, I am willing to trade an Ultegra for it...

So what ya got!?

I posted this here because I want to deal with locals in so cal.... thanks

Darn, I sold a Miche 12-27 to a different local BF member 2 months ago. But I have to ask, if it's going on a trainer, why bother worrying about the gearing? Matching your riding wheels won't matter because the resistance isn't that accurate anyway. Not to mention you probably won't be using a 27 cog on the trainer in the first place.

Its for chain length..... Plus I will be using this wheel as a back up as well....

I don't see how the smaller cassette would be a problem with the chain length. After all, you're simply spanning a subset of the bigger cassette's range.

I found a 12-26 at my local rei on sale for 25.00.. It is sram but works fine for shimano.. Only the last 2 gears are different than the 12-27.. It is 21-23-26 instead of 21-24-27..

http://www.rei.com/online/store/ProductDisplay?storeId=8000&catalogId=40000008000&productId=47928289&parent_category_rn=4500780&vcat=REI_SEARCH

Its for chain length..... Plus I will be using this wheel as a back up as well....
The difference in circumference of a 25T vs. 27T sprocket isn't enough to affect chain length. I've swapped out 12-25 with 12-27 without problem. But since the only difference between the two cassettes is the last 2 cogs, at least on a 10 spd., I wouldn't worry about it. And if you want to use the wheel as a back-up, wouldn't it be nice to have a different set of ratios? Just thinking out loud.:)