I'll echo replies here. 275/60 on 15x8 w/ 4" BS is 1/2" from frame rail on each side on my car. Going with 7/8" more BS but only a 1/2" wider wheel I bet would rub when cornering. Small spacer and extended lugs might get you there.
For other reference I looked at a few other club cars last weekend with 275/60 on 15x10's with 4.5" BS and they had around 3/4" clearance to the frame.