I run my 2.15 BAs at 35psi rear, 30 front, but I noticed last Friday that I definitely need to put more in the rear when I've got the rear rack loaded up after a trip to Costco. Going up and down curbs was much harsher, had to slow down or risk banging the rim up. I'll probably run the rear at 50 or so when I finally get my Ortlieb panniers.