I used to run 32x11.5 on stock 15x8 rims (5.5" BS)
I had a 2" suspension lift and things were still tight.
Had to put some washers on the front steering stops.
Things were really tight in the rear wheel wells but amazingly had no rubbing issues - perhaps I'm lucky or just not hard-core enough
Results will probably vary with different tire manufacturers having slightly different sizes.