Right now on my truck I am running 235 tires and 4:10 gear ratio. This is the setup that was on the truck when I bought it. I am looking into getting new tires and was wondering in anyone has any info on what size tire I should get without hurting the performance and fuel economy to much. I want to go bigger but I am not sure how big I can go. Any information would be appreciated.
A slightly taller, but not wider, tire might increase your fuel mileage on the highway. In town it likely will stay the same, or drop a little.
265'S should fit and the biggest I would go. Guessing almost a 1mpg benefit. I'd spend the few extra $$ for E rated (10ply) tires.
I am guessing you have a LT235/85R16. Your tire is about the same height as a LT265/75R16 and you may lose a little mileage by going to the wider tire. There really isn't a taller tire in that width. To go larger, you would have to look at getting different (wider) rims to run something like a 285/75R16 or jump to the 19.5 inch rims and tires.
Go here: http://www.4lo.com/. On the left side of the front page, there are a number of simple calculators like effects of gear ratio swaps, tire size swaps, metric to standard tire size conversions, etc. Just type in the numbers and click a button.waytogo
On that truck I would go with 255/85/16's. You can find most of the big brand names in this size and a load range E. It should be about 1.5 inches taller, just under and inch wider, and should fit up just fine. Should help your mileage on the freeway provided you correct your speedo for accurate calculations. I would expect to see 1-2 MPG when driving the same way. Make sure they are inflated properly. For mileage, go with a streetable tread pattern. Don't put on a set of Mudders, go AT or HT and it will drive better and get the fuel mileage you want.
If the truck is an 05 then youhave 17' rims. I run larger tires than stock so I don't know if my mileage is right.
