i Got new Jeep XJ (factory) 1999 model
with 3 inch lift kit
just added 32 Tyres and its performance is slow so want to buy ring and pinion. want help about best ratio for ring and pinion to add for that tyres size.

 

The easiest way to come up with the right ratio for your tires is to use the formula that gives you the RPMs for your tire height.

MPH x differential ratio x 336 / tire height x top gear ratio = RPM for that speed

Example: 70 x 3.55 x 336 / 32 x .75 for an auto = 1957 rpms at 70 mph

1957 rpm should be about what you are turning at 70 mph. You should probably
go a little lower to make up for the rolling resistance of the taller tires.

Maybe something like this?
70 x 3.73 x 336 / 32 x .75 = 2056 rpm at 70 mph

Or if you want power something like this?
70 x 4.10 x 336 / 32 x .75 = 2260 rpm at 70 mph

 

is it an auto or manual what engine does it have these facts affect what ratio you currently have

 

If you look under his vehicle profile it states he has an automatic. That is why I did the examples with the automatics over drive ratio.

 

Seeing as there might be a language barrier (based on location and username), I'm just going to say: 4.10

 

thanx for help ... i want more horsepower ,,, any advices , ?