Tires on Stock 04 f150 18'' wheels
 

I am going to put a 2.5'' leveling kit in. I plan on getting a set of 33'' tires but i don't know how wide i can go with the stock 18'' wheels. And on any wheel how wide can you go w/o having to get new wheels
Sorry if this is a beginner question but I can't find too much info on it. Thanks.

Typically you want to stay within 3-4" max of the width of the tire to the width of the wheel. Sure you can fit wider, but they could wear strangely.

The 18" wheel is 7.5" wide if I'm correct, hell maybe 8", having trouble remembering. You'd be fine with a 285, 295, or even a 305 width tire on that stock wheel.

i run 305 65/18 BFG's on my stock rims. not sure if i could go much wider. the inner side wall is about a 1/2" for the upper ball joint. truck has a 2" leveling kit

I have 285/65/18's and there is no issue what so ever. The next time I get tires I will be going to 295/75/18's.

Thanks for the info. I kinda came to the realization that i need knew wheels. I want them to stick out an inch or two. I've done some research on offset and backspace but i can't really rap my head around it. can you just explain it as simply as possible or even better could you just point me into the direction of what type of rims i should get

For about $650 you could get safe wheel spacers and keep your stock wheels.

Same here. No problems.

is there a metric equivalent?

most of the input above IS metric related?