What Is The Biggest Size Tires Can I Go With?

[RayGMC]

My stock 20's are getting bald so it's time to put some meat on them. I prefer Nitto TG or Toyo AT. Stock tire size is 275/55/20. Is is possible to put 275/60/20?

[BruceW]

I measured on my stock SD and found that 33" tires would fit just fine.

 

The stock 275/55R20 tires have a 32" outer diameter. 275/60R20 is 33" outer diameter. Your speedometer will be off by 2 mph at 60 and you will probably reduce your fuel mileage.