I was looking at getting new tires and rims for my stock 09 Ram 1500 Laramie Crew. I have 3.21 gears and was thinking of going to an 18" wheels (came with 20") and tires because of cost.

My question is, if I go with an 18" wheel will I increase or decrease my towing. Will I increase or decrease my mpg? If I go with the 18" wheels, what size tires would I want to go with to optimize both.

Thanks,

 

The other stock setup is 17" rims, which increases the tow rating somewhat.

 

I was thinking about 18" wheels but the tire selection is somewhat limited compared to 17".

 

I'm going with 275 65 18 Nitto Terra Grappler AT

 

Your mpg & towing will depend on whether or not you change the tire diameter. The stock 20" wheel has a 33" tire so if you stay with a 33" tire then nothing will change. If you go with a 31" tire on an 18" wheel the tire/wheel ratio will be the same (as far as looks go) but it will be like you changed your gears from 3.21 to 3.41ish which will help you in the towing department and will have little to no effect on your gas mileage.