Tire/suspension help.
 

I have an 2003 chevy silverado ext. cab and as of right now i have some 255/70/16 on it with aftermarket rims. I plan on putting a 2.5in leveling kit of the front of it. The problem is I want to put to add some larger tires so it does not look funny and I don't want to change rims as I just bought them. What do you think is the biggest tire i would able to put on without getting new rims?
Thanks, Drake

I have a 2 inch leveling kit on my GMC Z71 and I run LT285/75R16 tires.