Choosing ratios depends on what you have and what you are doing with it.

Auto AW4 or Manual AX15?
90% street/10% trail or 10% street /90% trail?
Highway driving?
Do you care about fuel mileage?
Engine mods? stock/bolt on's/supercharged

Being honest, we are about 80% street/20% trail-
AW4 stock 3.55 gears 31" and 32" was a dog compared to stock size tires.
AW4 stock 3.55 gears 32" +Supercharger was amazing. Plenty of low end engine torque to accelerate and great highway cruise speed and rpm

AW4 4.56 gears 32/33" sucked. Crawled well and screamed on the highway.
AW4 4.56 gears 35" great combo.

 

I found this handy tire size chart which made this calculation easy. Apologies if this had been posted previously. http://www.jekylhyderacing.com/HeightofTires.htm

 

New in Hobby question:: I have a 1997 Cherokee . How i can determine my differential specifications. Previous owner says that differentials are the original and the rear is a Chrysler. The Cherokee waslifted 9" with 35 tires. It is OK or i need any mods.

 

I have stock gears in a 97 County XJ lifted 4.5 inches with 33's. The gears are 3.55's. I have a limited slip in the rear and an ARB in the front. Can I change the gears without 1- changing the carriers and 2- having to get a different ARB and 3- will the limited slip have to be changed. I am afraid changing the gears will get pretty expensive due to my current setup.

 

If your rear is an 8.25 you can keep the limited slip since the 8.25 has no carrier break. The front Dana 30 you will need a different carrier for any gear lower than 3.73.

 

Can I use the ARB that I have installed in the current D30?

 

Unfortunately no, you cannot. You have part number RD101 for 3.55 and down whereas you would need part number RD100 for 3.73 and up.

 

^^^ What he said.

I'll buy your ARB to help you recoup some of your money haha

 

Everyone told me my stock gears should be 3:55’s in my stock 2000 XJ 4.0 automatic D30/Chrysler 8.25.
My understanding is the best I can stuff in the D30 is 3:77’s.
This would be good for a pavement princess lifted 4.5 with 32’s?

 

You get get gears as low as 5.13 for the Dana 30 but I wouldn't go any lower than 4.56, because the pinion gear is really small on a 4.88 or lower gearset. Going from 3.55s to 3.73s would be a waste of money.

 

He can use any gear ratio, but I think he is talking about the need to change the carrier if going below 3.73s. The open carrier isn't expensive, and won't make much of a difference when you figure in the cost of having someone setup the gears.

 

Thank you jedijeb. I was hoping I could run something in the 4.10 range.

 

for a 35in tire what gear ratio would anyone recommend, looking at 4:10 looking to build a crawler.

 

4.56 if you have the stock Dana 30 in the front.

 

4.56 should be the highest gear ratio for 35s. 4.88s in a d44 and 5.13s in tons would be a nice crawler setup on 35s. Currently getting around 18mpg with 4.56s and 35s myself.