whats a good width size to go with? 7.5? 8.0?

the guy at the shop gave me a rim and tire package of exactly what i wanted and the tires were 245/45/18

how much wider are they going to be compared to my stockers?
thanks in advance

 

Personally my mantality is to stuff the widest I can without causing problems. So I would say get the 18x8.0 wheel and 245/45/18 is the right tire size that you need. Without knowing the exact mm to in conversion off the top of my head...but I would say its probably about 1 1/2" wider than stock.

 

Tire size calculator

 

I just installed 18x7.5 wheels with 245/45/R18 size tires ... no rub... they fit very good and i am very pleased...

when you get done i can't want to see how it turns out!!!