Jeep JK General Information

Jeep JK General Information

JK Front and Rear Drive Shafts

 

For the Jeep JK's we can build the drive shafts using either 1310 or 1350 series U-Joints. If your JK is the Rubicon Model we suggest the 1350 series drive shaft due to the lower gear ratio in the Transfer Case. Also if you are running larger tires but the stock gear ratio we highly recommend using the 1350 series Drive shaft. If you are geared properly for your tire size and you do not pull a heavy trailer or beat the vehicle then 1310 series should serve you well. Our drive shafts work well on modified vehicles and you will need at least adjustable upper control arms for the rear to achieve the proper pinion angle for the drive shaft to run smoothly.

We use our Gold Seal U-Joints standard. Spicer Grease-able (with the grease fitting in the body of the cross) or Non Grease-able U-Joints can be installed if preferred at no additional charge.

Please see below for help determining the best size for your vehicle or call us with your vehicle info and we will gladly go over the options with you.

Need help deciding which drive shaft is right for you?

If your drive shaft is not properly sized for the tire diameter and differential gear ratio along with how and where you drive, you could experience problems with breaking the universal joints or other components in the drive shaft. We don’t want you to have problems.

The following is our suggestion, which requires a little math and for you to be honest with yourself about where and how you drive.

Use this formula; 20,168 divided by the tire diameter then multiply the result by the gear ratio of the differential. For example 20,168 / 37 = 545.08 X 4.1= 2,234. If the number you come up with is near 2,500 and you do not beat the vehicle, you should be OK with a 1310 series drive shaft. If you drive it hard, we suggest the 1350 series. If your number happens to be less than 2,200, we strongly suggest the 1350 series. For the JK Rubicon you should add about 10% to the numbers do to the gear reduction in the t-case.

If your number happens to be 2,500 and you do beat the vehicle but want to save a little money, consider this compromise. Run a 1350 on the rear and the 1310 series on the front. Some compromise can be made on the front drive shaft because when the vehicle is climbing a hill where there is more load on your drive train, the weight of the vehicle tends to transfer towards the rear and the front drive shaft is typically less loaded.

If you are on the fence about what size of drive shaft to select, please keep this in mind: I have never seen our 1350 drive shaft, for the JK break, because of torque. We cannot say the same about the 1310 series. The cost differential is minimal at $170.00. If you are like us we would rather be driving down the trail, un-broken, than sitting by the trail with the remote possibility that we still have the $170.00 in our wallet. Most people see, and understand, this reasoning, and will buy the 1350 drive shafts. This approach has substantially lowered our problems of a drive shaft breaking because it was under-rated for their vehicle.

If you have a lift in the vehicle, you may need something to rotate the differential for the CV type drive shaft. This is typically done with adjustable control arms.

Installation is a simple bolt in. You should have available for possible use; an impact wrench capable of delivering 180 LB/FT torque. Box end wrenches of the following sizes 1/2”, 7/16” & 18MM along with a 1-1/4” socket.

 

Read what Four Wheeler's Sean Holman says about our JK drive shaft:

 

Tom,

We installed the shafts today. They went in without a hitch, perfect fitment. If there was ever such a thing as a beautifully crafted driveshaft, these are them. Gorgeously constructed, they look like pieces of mechanical art and the guys at the shop were impressed. My vibration at 70 is gone and they are baby butt smooth at least until 80mph or so. These are the smoothest, truest aftermarket shafts I have ever installed. All of my future driveshafts needs will go through you. Thank you for the support of Four Wheeler and thank you for such a quality product - a rarity in these days of cost cutting.

Sean P. Holman
Tech Editor - FOUR WHEELER Magazine
www.fourwheeler.com