Right now i have 325/60/18s they are WIDE!

I want some street tires proxes, ziexs, etc. Now the only size i see them come in is 285/60/18, how much wider are the 325s compared to these? Also i have 18x10 wheels will they fit on there?

 

40 millimeters wider

 

So roughly 1 1/2 wider, will they fit on my wide wheels?

 

A 10 inch wide rim will work with either size you have listed

 

Ok great

Now i need to know what the backspacing on my rim is, i want the truck to still look aggressive with narrower tires on it.

 

Just lay a straightedge across the backside of your rim and measure to the mounting surface that goes against your hub and that will be your backspacing

 

Thats what im doing hopefully its 4.5 or less

Street tires are sure cheap!