tryn2lrn

Depends on what wheel tire combo you have. 20s are 75rear 65front and 20% is right so that's minimum 60rear 52 fronts. I had the dealer remove the 20s and put the 18s on my truck when I bought it which are 70rear and 60front which work out to minimum 56rear 48fronts. They would only reprogram to the GM specs for the 18" wheel tire combo. Even though I explained technically I replaced the factory installed wheels and tires with something other than what came on it stock. Didn't matter they wouldn't do it. I just wanted another 5lbs lower. I worked around it. Empty there is no need for the backs to be above 50. I have been hauling and towing all my life, I know how to regulate air pressures based on usage.