Hello everyone,

I think I have visited every post on this forum having to do with what size tires will fit these trucks and what size tires won't. Unfortunately, they are virtually all about 4x4 trucks.

I have a 2wd, '04.5, auto, 3500, with 4.10 gears (SRW). I've been wrestling with myself concerning gear ratios. I usually run empty; at most I tow a 4000lb boat. I'm looking for the best way to perhaps slow the revs at highway speeds, pick up a mpg or 2.

One way to slow down the rpm is to install 3.73s. The other way, of course, is to go with a taller tire.

However, one problem with larger tires is they have a wider section width than the stock 265/70s I'm running - aerodynamics does play an important role in fuel mileage.

I guess I have 2 questions. I'm taching about 2175 rpm at 70mph. I can get to about 1950 rpm at 70mph with changing to 3.73s and staying with the 265 load range E tires stock tires. Am I likely to see an increase in fuel mileage with the change in gearing?

The second question is this. If I choose to go with larger tires instead of the gear change, what size tire can I use with the bone stock 1 ton 2wd? If I go to 285/70s it looks like I'm stuck with load range D. The reduction of rpm would be about 100. Will 285/70s rub without raising the front with Daystars or something similar? The only load range E I know of that might work is the 285/75 Toyos. They are 2.5" taller than the stock tires with the same 3/4" increase in section width of the 285/70s? Would the 285/75s be likely to rub?

Suggestions on which route to take - gears or taller tires - and likely fuel mileage results would be greatly appreciated.
Thanks

 

If I had a 2wd, Id really look into a gear swap. Since you dont tow much, the 3.42s would be great and would really make a difference for highway driving. I had to go with the taller tire approach on my '04 4x4 w/ 4.10s and picked a 295/70. I can now run 70-72mph in the 20xx rpm range. I just got 20.1 mpg at these speeds on a 650 mile trip. However, I have no idea if they would fit your 2wd up front.

 

I have a 06 2 wheel, with 373, and I wish they had the 342 as an option at the time I ordered mine, I would do the diff swap, putting 33 or 35 inch tires on a 2 wheeler looks pretty funny, I dont even think it would cost that much to change out, Ive left mine as I pull a trailer between 7000 and 10000 pounds, good luck

 

Ring and pinion from Dodge Dealer is $ 350 including bearing and seal. I would do the swap.

 

Thanks for the replies. I was leaning toward the gear swap. Your comments seem to confirm that is the best way to go.