I have a 2005 f250 4wd with an 8inch lift And 37 inch tires. I currently have 410 gears.

What gears are you guys running with 37's. What's your rpm at 65. Mpg? Did you notice a difference in power?
One more question. Will 4.88 gears fit in the front and rear without needing anything else like a new carrier?

 

I have 3.73 with 37" tires. I'm about to change to 4.88. the overhead console says i get 8.1 mpg and i turn close to 2500 at 75mph

whats your MPG with 4.10?
RPM's at 65 OD and non OD?

Thanks

 

I turn 1700 at 65 in od I get about 9

 

4:88's..

for sure.

 

Sounds like your not shifting into OD.


If your speedo/abs system isn't corrected for the larger tires you will not get accurate mpg figures.

A set of 4.88 gears with 37s will yield an effective ratio of around 4.22 with stock tires. A set of 5.13 gears will have an effective ratio around 4.44 with stock tires. I'd say 4.88s will work very well, if you do a lot of heavier towing the 5.13s may be worth looking at harder.

 

Why do you have 8" of lift with only 37" tires. Are you planning on bigger tires, if you are then I would go with the 5.13's