Compact vs Triple

[melissam]

TBird,

I honestly don't think that a 34-27 will make a huge difference on hills vs. a 34-25. According to Sheldon Brown's gear calculator, a 34-25 will give you 35.7 gear inches, and 34-27 will give you 33.1 gear inches, assuming 700c wheels. Helpful, but not a huge difference on the hills.

Please keep in mind that this comes from someone who not only has a mountain cassette, but also a triple! I have to say that having my 30-34 available gives me great peace of mind on many a ride. I might not use it, but it's very reassuring to know that it's there.

One more thing: I rode with someone who had a mountain cassette with a 32 in the back, and he was able to use his Ultegra rear derailleur. You would just want to be careful and avoid shifting into the 32 while you're in your big ring. It's not something I'd do on purpose, but I can't guarantee that I wouldn't have a very blonde moment at some point during a long & strenuous ride.

- Melissa