GMC C4500 tire size
The most common factory tire size for the GMC C4500 is 225/70R19.5, on 2 of the 2 year and trim fits listed. Each year below lists the sizes its trims were built with (2010). Pick your year and trim to see the tires that fit.
Check your own tire
A trim can be sold with more than one wheel size. The size printed on the sidewall of your current tire, or on the placard in the driver's door jamb, is the one your vehicle has.