on my 15x7.5 im running a et street radial 325-50-15 and love it!! i get 1.6 60s on them and they work awesome on the road. i use to have a set o 275-60-15's but when i ran them my suspension was wack(bad ladder bar install) so i cant speak on how those hooked up. but i kow three different 11 second fox bodys around here that run the 275-60-15 and have no problems.