Tire size question for 18 inch wheel

I've seen alot of "biggest tire on stock suspension" posts for 16 and 17 inch rims, but what about 18s on a stock 09 4x4 Sport Dbl. Cab? The wheels in question are 18x9 with 4.5 bs & -12 offset. I've searched and even toyed with the tire size calculator, but I haven't found anyone running 18s without a lift and the calc seems more theoretical than definitive. If I were to stick to a 17 inch wheel, I know 265/70 is the biggest I can go. But is that just on the stock wheel? What about an aftermarket one that's wider? What does that do to the fitment? If the rim is wider would going to a 275 be the way to go? Ideally, I want to go 18s with the biggest tire possible. Thanks for any help on this! I'm itching to get some new wheels!

 

The width of the wheel will affect fitment somewhat, but the BS/offset is more crucial. That -12mm offset will stick the wheel/tire out a bit and therefor give a larger arc when turned L&R. I dont know alot about what sizes you can find in 18's, but some examples that should fit would be:
265/65/18 ~ 31.5x10.5R18
275/60/18 ~ 31x10.8R18
285/60/18 ~ 31.5x11.2R18
Some minor trimming and removal of the front mud flaps may be necessary with the larger of these sizes. Ideally a wheel closer to a 0 offset, or even very slightly positive offset, would be better than that -12 spec on the wheels you're looking at for trying to fit the tallest size possible. If you were wanting a wide tire, then you would want to stick to the negative, or 0 offset as a positive offset on the wheels may give rubbing issues on the UCA with a wide tire.

 

Thanks for the info! I'm thinking the 265/65/18 would be the best option. Is anyone running that size on here? If so, I'd love to see some pics. If not, I'll just have to do it and post some of my own.

 

That is the same setup on the XSP model which the same height as a SR5 or TRD so you will have no issues. I am putting the same setup on mine with a 0 offset.

 

4 year bump