3.73 to 4.10??

[FastFocus]

So, i know i have to swap out the front end as well, but i'm curious as to who's done this and how much quicker the truck has felt after its done. I'm thinking of doing it however i'm concerned about the decrease in fuel mileage that i may get? I will be going from my current 33's to 35's sometime in the near future as well.

is it a good idea or bad? And why?

[Evil Eye]

Actually, it may offset your increase in wheel size and so your fuel mileage might actually stay the same. You are probably slightly lugging the engine now with your 33's when you are just cruising.

[tbisme]

lower RPM = Better fuel economy
So, here is a calculator to use it is kinda backwards for your info but it will work and it is simple enough. Just remember the best economy you can get in these engines is close to 2000 rpm so use that and your tire size and the speed you drive.... if you use 80mph then at 70 it will be less rpm, obviously. Hope this helps.

Differential Gear Ratio Calculator