another endorsement for Serotta fitting here! while I was out on my medical leave from riding, I got a fit at PK Racing in Fairfax, CA. this is all they do - bike fit and analysis - it took 3 hours and he made adjustments from stem to cleats. the owner, Chris, was head instructor at the Serotta fit school for a time.

anyway, since I have been back on the bike I really feel a difference in the fit - so far none of the nagging low back pain I might otherwise get on a long ride. (so far my longest ride was about 188 miles, but I will be doing longer rides as the year progresses.) also, somewhat surprisingly, my descending feels a lot more solid as well.