When you add larger tires to your Jeep, it throws off the powerband, transmission shift points, and more. This also translates to lost off-road potential. In short, the Jeep won't pull itself through or over certain obstacles without the proper gearing. To counter this problem without a regear, many drivers usually apply more throttle or slipping of the clutch. This can cause damage on other components, such as premature clutch wear, snapping a driveshaft, axle shaft, etc. When you regear your Jeep, you reset the relationship between the powertrain and the wheels close to OEM spec. This means that the transmission will shift properly, the Jeep will "pull" in between gears as it should, and 4hi/low will work effectively on the trail.
There are many charts and diagrams on what gears you should get for your Jeep. Regear factors range from engine and transmission type to tire size, and more. With the 2007-present Jeep Wrangler JK/Unlimited, you'll need a programmer for your new gear/tire setup. We recommend the AEV Procal. If you have an older TJ/YJ/CJ, you're good to go with the gears themselves! If you're unsure of what gears to choose for your application, don't hesitate to give us a call, we'll lay out your options and recommend a new gear ratio for you!
When tricking out your Jeep and venturing offroad, you should also look at your axles, and decide on an upgrade, or alternatively leaving them OEM. You may need to upgrade your axles if your tire size meets or exceeds 37" on all Jeep Wrangler JK/Unlimited models, excluding the Rubicon. On the Rubicon, the HD Dana-44 axles are fine for 37" tires, although we wouldn't recommend anything larger. If you're going larger than a 37, we recommend a set of '60 axles. MOPAR, Dynatrac, and TeraFlex come to mind if you're thinking of an axle swap. Shown below is a Jeep Wrangler TJ Brute Conversion with a set of aftermarket TeraFlex 60 axles.
On the Non-Rubicon JK models, we suggest an axle shaft upgrade or a truss/gusset set up on the OEM Dana-30. All Non-Rubicon 4WD Wrangler JK's come with a Dana-30 front end. This axle is great for the weekend trail 'rig running 35's, but throw on 37's and hit the rocks, and you could be in for trouble. It's better safe than sorry when it comes to your front end, so give us a call if you're looking at upgrading your Dana-30!
The Rubicon Wrangler JK comes equipped with factory lockers. Most Non-Rubicon Jeeps will feature open differentials from the factory. The end result in an open differential 4WD system is more like 2WD off-road. If one of your front and one rear wheel is in the air (or in another, low traction substance, like mud), in an off-road scenario, power will go to those wheels. You'll sit there spinning tires and won't go anywhere.
Lockers, like the ones found on the Rubicon, fix this problem. With a locker, both axle shafts are locked together. This means that even with one wheel in the air, power will go to both sides, not just the one with the less resistance. The end result is that you'll have true 4x4, with all four wheels turning at once, as they should. And you'll be able to climb up, over, and through off-road obstacles more effectively!
If you don't have lockers and would like to upgrade, there are many aftermarket types and brands, from ARB to OX, electric to air or cable actuated, and more! For most Jeep Wrangler JK owners, we recommend an air or electric actuated locker, such as ARB. ARB has a wide selection of air actuated lockers, which are powered by a small air compressor under the hood. With a flick of a switch, the compressor and lockers activate, giving you the extra capability to get off the beaten path! Turn the compressor and lockers off, and you've got open differentials again.
Automatic or Lunchbox Lockers
If you have a dedicated off-road 'rig or locking hubs, you may want to explore other options, such as automatic lockers, which are a cheaper, more basic locker - i.e., as long as power is sent to the axle, the locker is on. To note, this is not optimal in the rear axle, especially on a daily driver. However, an automatic locker may be an option for the front, depending on your build. Again, if you have locking hubs on the front end, or drive an older vehicle, this may be an option to consider. Give us a call if you're having trouble deciding which locker is right for you!
What You Get Off-Road
The benefits of a Jeep with the proper gears, lockers and axles while off-road is miles beyond that of an OEM vehicle. With the right setup, your Jeep can take on the toughest trails around! While open differentials mean that you'll be backing up time and again to get momentum or find a new track, lockers and the proper gearing will allow you to approach these obstacles with confidence. Upgrading your axles lets you push your 'rig that extra bit, to get yourself or a friend out of trouble, without the fear of rendering your Jeep inoperable with a broken axle shaft or housing. From the mild to dedicated off-road 'rig, these upgrades will let you get the most out of your Jeep - find out what you're missing and give us a call, today!