Paul731

I merely changed the set of tires from 275 55 R22 to 275 60 R20 (due to driving on rough roads) and the tire shop said that will be 2.something % smaller diameter (a closer one would be a 65 wall = 0.7%) anyways; the super cruise does work sometimes but not as much as it is with stock size tires I also asked GMC if I can lift it, I got the same answer as the GM rep answer above it comes down to this I guess; is your SC picking up on the same roads before and after the lift? Or it is picking up on some roads?