A little bragging and a question

[girlsubobscura]

After doing two (sprint distance) triathlons on my commuter bike (a flat bar hybrid) I am now the owner of a new-to-me carbon fiber road bike which I am super excited about for longer recreational riding and more tris. Its a 2007 trek 5000, and came with shimano spd pedals. I didn't like the saddle it came with, and am replacing it with a specialized Jett 143, which was a saddle I really liked when I test rode an Amira a few weeks ago.

The folks at my LBS have a pretty good reputation for bike fitting, and I am considering paying for a complete basic fitting when the replacement saddle comes in.

I've ridden the bike at this point only 12 miles, and its been freezing cold and raining everyday since. It felt pretty good, except the recurrent nerve buzz between my neck and left shoulder (which developed after riding my commuter for longer distances) is still there. If I am planning to ride this bike aveage distances of 20-40 miles, how important is it to get in a ride of that distance in before the fitting? What sort of questions should I ask my fitter? Any advice on my specific issue or general fit etiquette would be appreciated.

And now for the bike porn I am a little giddy at the prospect of having such a fancy bike.