Originally Posted by oakleydo
Is the difference between the 3700 and 4500 substantial? I am considering upgrading, but don't want to spend $ on something that is not going to be a big jump in quality. I've compared the specs, of course, but being a newbie, am not sure of the difference in quality of the components.
Meaning you have a 3700 and are considering buying a 4500? I think you'll definitely notice an increase in quality, but if you really feel you've outgrown the 3700, you should probably consider spending the extra money on a 6500 or higher to make sure you have a ride that will fit your needs for several years. Also, if you are buying a new bike, remember there's other options besides Trek.
Sorry if I misunderstood the question.