I just lowered my 87 GN with the belltech 2" drop spindles and the tires are rubbing over the littlest bumps. I have 245/60/15 all the way around. What size tires do I need to have no rubbing at all? Or do I need different shocks or what? thanks
The best way to lower a G-body using the stock springs is to use an aftermarket Lower Ball Joint that is taller. This will improve the vehicles handling AND reduce the tendancy of the top of the tire to smack the fender every time you hit a bump (with the stock geometry, when the tire goes up, the top of the tire goes OUT - bad).
Drop spindles have always been more for looks than any performance or handling improvement.
Aftermarket, stiffer springs can also help. I ran 245/60's with T-type Wheels using Eibach lower springs and never had a rubbing problem
The Upper Control arm bushings could be causing the majority of the problem, but there is good chance after they are replaced, 245 wide tires will still rub some with drop spindles.