My Castelli bike shorts have a chamois that is sewn on with nylon thread. The shorts were fine for 10-15 mile rides, but I'm starting to go further. After a 35 mile bike ride this weekend my rear end & crotch were raw & sore from rubbing on the seams. I do not ride with underware and use "Butt-R" creme which is supposed to prevent this sort of thing. I am desperate to find bike shorts that do not rub in this area. I will soon be going on a 2-week, 30-60 miles a day bike tour & need to find something comfortable or I won't make it. Does anyone else have this problem? Any suggestions or recomendations? Thanks!