The bolt pattern is 5 on 114mm..same as Mustangs, I think. As far as how big can you go? That's a good question. I think I saw a guy on Street Source who had a set of 20s on his Taco, but I'm not sure how impossible that would be to tuck. I do know that with most any larger wheel, you'll need a t least a +42 or even +44 offset to be able to tuck those bad boys.