38/38psi (When I got mine sone guy on this board said from his tests this was best so it must be true) on my '04 w/BT020 Stones and just changed rear w/13.5Kmi and front is badly cupped but has another 1/16" to go before the wear bars show. Front tires cup from the tread being distorted (and wearing that way) by the side forces when turning. I sorta like that sound. Go streight & they won't cupp as much...Later,,,De :rollin