Vibrato,
I don't know exactly how many minutes or miles I wore mine at the MWMBF and Sugar Bottom on a different occasion , but I know it was way more than 90 min. I rode, ScoCoPa (10-11 miles ?), Illiniwek (5-6 miles ?), and Sylvan (at least 6 miles there that day) all in one day wearing them. I rode 2.5 laps at Sugar (guessing about 30 miles or about 3.5 hrs) wearing them the other day.
All I can say is that once I got the elastic around my thigh situated to where I like it; I literally forgot I had them on for awhile (I even mentioned that to someone I was riding w/). All that and under $60? I'm sold!
Only thing I wish they had (not even sure if there is a pair out there w/ this feature) is a waterproof pocket from the inside out b/c I sweat so much! I want to protect electronics from sweat. It has this awesome pocket and loop for an MP3 player and running the cord through, but I am afraid to use it until cooler weather b/c I think the MP3 would eventually get too much sweat on it from my sweat factory!