[TJ 98]

I've been thinking about lifts and larger tires since before I got my first Wrangler. Now that I have it, the questions remain in my head.

First, about the Jeep:

'98 Wrangler 2.4L (all stock), manual, 31.6" tires

I would like to be able to put 33's or even 35's on my Jeep. I realized that this would require a regear...

First, I know it really doesn't matter too much, but I'd like to know what gears I have on it currently. The differential does not have the ratio marked on it. I took my Jeep on the highway this weekend and logged two RPM guages for two different speeds.

-2600 RPM at 60MPH in 5th gear
-3000 RPM at 70MPH in 5th gear

I was wondering if there was a formula or equation that I could use to get the gear ratios from these numbers?

Next, what gears would be recommended for a base Wrangler with 33's or possibly even 35's on it? I've done a little research, and I've heard 4.88s? Also, would I need a new axle as well?

Thanks in advance for the information.

 

[Water Dog]

Jack up the rear end of your Jeep, put a visible mark on your tire and your drive shaft, turn the tire one full revolution while counting the number of revolutions your drive shaft makes. That is your gear ratio.

 

[TnDz TJ]

5th gear is OD.... do the same test in 4th gear ( 1:1 ratio ) and post results for 60 and 70 mph.....

OR..... do the above....

 

[toms01TJ]

Use this link to figure out your current grearing, and future gearing options...

Gear Ratio Calculator

Stock tranny should have been a NV1500, IIRC.

4.88 gears would give you your current 3000 RPM @ 70 MPH in 5th gear.

If your axles are stock, I believe that you will need to change the diff carrier to go any lower than 4.88's.

 

[Jerry Bransford]

Your four-banger engine is a 2.5L, not the 2.4L that came along much later. The transmission you have is the AX5 and your axle ratio is 4.10/4.11.

Your rear Dana 35c is not up to 35" tires, it is only strong enough to remain reliable with 33" tires. 4.88 would be the appropriate ratio for the 2.5L engine, 5-speed transmission, and 33" tires. If you see recommendations for 4.56 for 33" tires, that recommendation is only correct when the engine is the 4.0L.

 

[TJ 98]

Sorry, I honestly meant to type 2.5L. Stupid typos Thanks for all of the information guys. I was thinking that I'd need new axles for anything over 31", but if the Dana 35c will be fine with 33's, thats great news.