I have the stock 245/70/16 Goodyears on my 08. How far can I go without needing any mods?

 

Assuming you're sticking with 16" wheels, 265/70/16 will fit 100% fine. Going up to 265/75/16 may fit, but you'll most likely need to do some trimming.

 

I have 265/75/16 they fit fine stock.

 

265/70/16s had a 1/4" of clearance with the front mud flaps on my truck before leveling the front. With a 1.5" leveling kit, I have alot more clearance. If you want to do any large tires/wheels, I suggest you invest in a leveling kit.

 

I too have 265/75/16's. They fit fine without a leveling kit.

 

What about bigger wheels? Looks like everybody has stuck with 16". I'd rather not mess with kits etc. I don't know the right person to do it and there are always some side effects.

 

You can go up to 20" wheels, if you want. I'm running 20's, you just need to have a smaller sidewall. 265/50/20 fit on stock suspension, guys here are running anywhere from 16" to 20" wheels.

 

I did not see a truck tires in that size. I like something like BFGoodrich All-Terrain T/A. What measurements should I look at when going with larger wheels?

 

Easiest thing to do is to use a calculator like this one:
http://www.1010tires.com/tiresizecalculator.asp

Type in what sizes were suggested for a 16" wheel, and compare them to different sizes available for bigger wheels. Use places like tirerack.com and tiredepot.com, or tire manufacturer websites to find the tire sizes that are available in a specific tread pattern.

 

265/75/16's will fit nice. But 70's will fit w/out any cutting. Once u go bigger wheels it may change the offset and make it rub. It did on mine.