I have just purchased a 2007 Silverado LTZ with the Z71 package. It has the 18 inch wheels and 265/65/18 tires. I would like to put larger tires on. Does anyone know the largest tire size that will fit with the STOCK configuration and if the new size is available in the ECM to make the speedo right. It appears that I may have a little over an inch of play between the front bumper and tire while turning, but would like some confirmation.

Additionally, will the addition of larger tires cause a problem with ABS. I have done this on older trucks with no problem, but once again, would like to know for sure. Any other concerns that I should consider is appreciated.

 

I have just purchased a 2007 Silverado LTZ with the max 6.0. It has the20 inch wheels and i was wondering the same thing. Just by looking at my 20's I would say one size higer maximum for me, not sure about the 18's

 

I have a 2007 2500hd and I put 285 Dick Cepek FC 2's on it. Not the 18 or 20 inch rims, but the most you will get for tire size is 33 inch regardless of rim size without rubbing. I have absolutely no room for any size bigger. They don't rub, but if I went off roading there is rub potential. Lift kits are available that will help, I know of a tortion key lift, and a full suspension lift ranging from $700 - $3500 Canadian.

 

I put a 2" leveling kit on the front of mine to raise it equal to the rear. I was able to fit 35 12.5 18 with no problems.