Quote Originally Posted by anakiwa View Post
Deb- What is it that makes you want to avoid the long cage?
I'll admit to not having ridden modern long-cage derailleurs, but from my experience of years ago, the longer the cage and the more chain-wrap and the further the top jockey wheel is from the cog, the slower and grindier the shift. For quick, crisp shifts, you want a narrow-range cluster and a RD not meant for anything larger.

Quote Originally Posted by anakiwa View Post
In all honesty, the gearing with my current triple (52/42/30 with a 12-25 cassette) probably suits me perfectly. It gives me a relatively low gear for climbing and it's only rarely that I'm pushing the top gears (Like you Veronica, I'm not a maniac on downhills- it's only on that long gradual descent that it gets tempting to see how fast I can go). But I find that the triple often gets slightly out of alignment and I'm having to really jam the shifter to get the derailler where I want it (someday I'll learn how to adjust these things myself, but for the moment I'm dependent on the LBS or the ex-BF- who isn't around as much as he used to be). My tribike has a compact and it's always been so much easier to shift. After studying the numbers I concluded that a 50/34 with a 12-27 would get me almost as high and almost as low and that I should be able to live with that. But it's a good point- maybe I should just stick with a triple- it would certainly solve the hillclimb problem.

So here's another question- anyone have any thoughts on whether an ultegra triple front derailler would shift more smoothly than my current 105 triple front derailler? (or is the higher price simply because it weighs less?)
Since you are getting a custom frame, one thing I would consider is getting braze-on mounts for downtube shifters, and using a DT shifter for the FD. I hear so many complaints about FD shifting on STI levers, and I recently rode a bike with STIs for the first time. I believe that STI levers and FD just don't work well together. DT shifters provide a direct connection to the FD with minimal cabling, minimal cable bends, no springs or levers or cams or indexing. When I worked in a shop, we never had complaints about FDs, and the FDs were probably not nearly as good as today's. Since one doesn't shift a FD that often, using a DT shifter is not a big hardship, and with a friction shifter you can always trim it exactly where you want it to center over the chain. The ergonometrics of DT shifters are far better, using your entire arm in a natural plane to apply the pressure needed to shift the chain to a larger cog - STIs depend strictly on finger strength. Just my 2 cents, and maybe nobody else would agree with me, but I love DT shifters. Though I can't criticize a rear derailleur STI lever for ease of use.