bfg 315's street psi???

This doesn't sound very smart... first of all, a 315 tire must look kinda goofy on a 17x9 cobra wheel. Secondly, why did you go through the trouble and cost of mounting bald tires? seems like a bit of a waste.

Anyway, what kind of BFG is it? They make quite a few different kinds of tires and the type of tire will tell you what kind of pressure to run. :stick: A drag radial? All season tire? Off road mud tire?

I would think 28-30psi would be good on an all season tire, while 14-16 would work well on a drag radial. And no, a 315 tire on a 9" wheel won't handle that well.