If my factory tire size is a 30" tall and I go to a 32" other than my speedometer being slow will it effect the shift points? The main concern is normal driving. It won't really be ran hard at any time. Its a 03 2wd silverado, 4l60e, 5.3. Thanks

 

It will shift later than normal because the PCM thinks you're going slower than you really are with the larger tires.

 

It won't affect the RPM shift points. It will affect where it shifts relative to MPH, though.

 

Tire size also effects the Brakes and ABS system.