Buffybike- we are like twins right now! My longest ride is about 66, and I'm training for a 109 mile ride Nov 20...And I have a Specialized Jett 143. My butt used to get tired at about 30-40 miles. It still does a little, but I find it that it's helpful to get off the bike for a few minutes here and there, and then it's okay again. I rode 60 miles today, with 2 or 3 ten minute restroom/water breaks, and when I got to the end of the ride, I wasn't noticing any problems.

We should keep comparing notes- I'm scheduled for 70+ miles next week, and maybe a century ride before El Tour de Tucson.