In short - fit makes a huge difference. Some simple adjustments a qualified fitter can make are things that are really hard to do on your own.

When I got my first fitting session for my road bike, I could ride about 10-15% faster with much lower perceived efforts.

I think its a very useful exercise and can dramatically improve comfort and performance.

Definetely worth it. Especially when it comes to tri bikes. You can gain up to 15% in efficiency alone. Not to mention being much more comfortable on the bike itself over long distances.

I paid $125 for a Serotta Certified fit last year. It was worth it since I hadn't been fit in years and as I've gotten older my body has changed...

Is there an easy way to locate FIST certified bike shop, or someone who is a biomechanics expert like Ken Mierke mentioned? I'd drive 3 hours away to spend $150 on 10-15% more performance on my bike. Problem is, there's so many bike shops in a 3 hour drive of me, it would take days to call each one and ask "Do you have a FIST certified person and a fit simulator?"

Given you're in the DC area - would you recommend the place you went to?

I wanted to circle back to this thread after I had some time to realize the impact of the fit I got. Back in late November I scheduled some time with Ken (above) to get my bike fit. I spent about an hour in total at his office where he mounted my bike on a Computrainer and procedded to work through numerous tweaks, including seat height, seat height, aerobar position. I would get on the computrainer and peddel for a short while, then he would change things and we would repeate a number of times.

Overall I would say it was WELL worth the $150ish that it costs. I wish I had done it last year before training for a whole season. Ken was great during the process, explaining what each of the tweaks was going to achieve. I also got a detailed sheet at the end with all of the exact measurement specificaitons so if I ever need to recreate those specs (such as after shipping a bike to a race), I could easily do so. It was also clear as to exactly what the points were that were being measured.

Thanks again Ken!

I wrote up a bit longer post/review/recap on my blog as well: http://dcrainmaker.blogspot.com/2008/01/bike-fitting.html

http://www.slowtwitch.com/mainheadings/techctr/bikefit.html

long read, but very informative

A bike fit involves positioning your saddle, seatpost, stem, bars, cranks, etc. forward/backward/up/down so that it is the most biomechanically efficient position for YOU to ride in. They may suggest a different stem length, bar width, etc. to fit your bike to you.