What gear ratio for 33 12.5 on my 99 Ford ranger, I currently have 3.73 but it's slow and I have to drop a gear going up hills. What's the best gear for those tires it's a 99 xlt 3.0 v6

 

Go here: https://therangerstation.com/tech_li...ioChange.shtml

Look on your drivers door label to see factory tire size
Say it came with 29" tires
33 new tires
29 old tires
3.73 ratio
Calculate

Actual is now 3.28

New ratio 4.24<< this would give actual ratio of 3.73 again

But there are no 4.24 ford axles, so 4.10 or 4.56 are the options, I would go with 4.56 for best low end power, but higher RPMs on the highway in 4th and OD, which is actually better for 3.0l Vulcan engines, they make best power at 3,800 RPMs

If you have 4WD BOTH axles need to be changed

 

I run 4.56 gears with 33" tires with the 4.0 engine. It works very well. It came from the factory with 4.10 gears and 31" tires. I think 4.10 gears would be too high for a 3.0 with 33" tires.

 

Agreed, I ran stock 4.10's with 33s on my truck for a few years and always wanted lower gears (4.56).

Rule of thumb for these trucks is:
31's - 4.10
33's - 4.56
35's - 4.88

But don't expect fuel mileage. lol.