Quote Originally Posted by liza View Post
Do shifters really make a bigger difference than derailleurs? I thought it was the other way around. Why do the levers make so much difference? (I'm asking this sincerely -- I really didn't know).

However, switching out to Ultegra shifters for $75 seems like a good deal. You might ask what they would charge to swap out the front derailleur too -- they're not a terribly expensive part to begin with (at least compared to shifters), so it might be worth an extra $35 if you could do it that cheaply...

ETA: FWIW, I have read that Ultegra brakes *are* considerably stronger than 105s. I have never used 105 calipers -- my 105 bike has cantis, so I have no personal opinion on this -- but given your impression, it might be worth googling for some reviews.

Also important to remember that how well the bikes are tuned makes a big difference in how well they shift -- I can remember test-riding an Ultegra bike that had buttery shifting, followed immediately by a Dura-Ace bike that had OK, slightly rattley, slower shifting... Sometime the bikes on the floor aren't kept perfectly tuned (and sometimes the mechanics who put them together do a sloppier job than one would hope the first time).
I agree. 105 brakes SUCK. (that's what I have and there are a couple of roads where I have to stop on a pretty significant downhill. major suck every time). DA brakes are supposedly awesome, but for the money, you can't beat Ultegra for value and performance. When I was bike shopping, I wound up with an Ultegra/105/FSA mix of components. Between the Ultegra and 105, the Ultegra is much much better. I will eventually upgrade the rest of my 105 stuff, especially the front derailleur which pisses me off to no end. There was a huge jump not just in components but in frame material between my bike and the next one up. I believe the same is true for the Trek. So, you will be getting a lot more with the 5.1. Now 105 levers can be a little "sticky" feeling, and I have to lube them up periodically. I think if you're considering upgrading immediately that you might want to reconsider the 5.1. If you want to postpone upgrading and you really want to stick with the 4.5 price point, then the 4.5 is good enough.