Well I have been searching for a good used truck. Finally today I found one. A 1999 2500 with about 83k on her. The only thing that I didn't like was that it had a 4:11 rear end. I have really been looking for a 3:55 for fuel economy reasons. When I test drove the truck the tach was turning 2k at 60 mph. It still had the stock tires and wheels.

I was thinking I could mount a taller set of tires on the stock rims to change the gear ratios a little. I believe a friend of mine mounted a set of 305s on his stock rims. so this should lower my rpms by about 2 to 3 hundred to help out the fuel economy.

any help would be greatly appreciated.

 

I'd just swap the gears in it. I've got 3.55's and haven't had any trouble pullin any of the trailers I've hooked on to.

 

If you plan on towing much the 3.55's suck I have a 98 with 3.55 and anything over 60 the mpg heads downhill. not to mention if it is windy out while towing. the 4.11 can get 20mpg if you stay at or under 65 and the truck is sutup correctly.
Stock aluminum rims will fit a 305 stock steels are a little narow

 

I would never buy another 99 to many headaches and replacements.
just my opinion.
Scott

 

A taller tire will help with the effective gear ratio. But a wider footprint of the 305 will offset much, if not all of the MPG gain.

What will the truck be used for? Mostly unloaded? Towing? If so, what, and how often?