What Really Makes Jeeps Incredible Climbers

For over eight decades, Jeep has had an established reputation as a brand for outdoorsmen and competition off-roaders. Despite releasing some comfier and more economy-minded models in recent years, that reputation is not for nothing. Countless overlanders still flock for capable off-road vehicles. The modern Wrangler series in particular still carries a lot of that rugged DNA and a lot of the heavy-duty equipment that makes Jeeps so capable off-road.

Some Jeep owners build their vehicles into extreme off-road machines known as rock crawlers. You can usually identify one by its giant tires, lifted suspension, cut-away body panels, and thick roll cage. Crawlers will also usually be packing custom transmissions that are geared less for speed, and more for torque delivery. This allows them to move very slowly over inclines that no other vehicle could clear. At a rock crawling competition, you might see some Broncos, and some Toyotas, but Jeep will be by far the most represented brand. Let's examine what makes these Jeeps so capable.

When it comes to transferring engine power to the ground, the simplest mechanism is known as the solid or 'live' axle. It consists of a sturdy steel tube, with a spinning shaft on the inside that sends energy from the differential out to the driving wheel. These axles are paired with an equally simple suspension design, using leaf or coil springs.

Nowadays, most solid axles have been replaced with independent suspension systems, which have continuously variable joints and thin exposed driveshafts for added flexibility. However, the CJ and Wrangler have stuck with the old solid axle design, which many off-roaders still swear by.

While an independent suspension is more capable on the street, it has some disadvantages. The CV joints that allow the system to bend are also vulnerable weak points while off-roading. A rock can bash into the axles and warp them, or damage the joints directly. A bad enough impact could even detach the driveshaft from its wheel, stranding the vehicle.

You'll have no such issues with the old-fashioned live axle. Since the driveshaft is protected by a thick layer of steel, it can take plenty of hits from rocks and keep on going. The simplicity of the design also makes it less prone to wear over time and makes suspension lifts easier to install.

Through much of Jeep's life in the 20th century, it was a subsidiary of the American Motors Corporation. During this time the Jeep brand became synonymous with AMC's venerable inline-six engine. This powerplant was available for every CJ model after 1972. In the mid-80s, AMC had to declare bankruptcy and was promptly bought up by Chrysler.

Despite new management, Jeep kept installing the 4.0-liter version of the straight six into many models, including the newly-christened Wrangler and the four-door XJ Cherokee. Chrysler kept on using the engine for another 20 years, retiring it with the last TJ Wranglers in 2006. The engine's long service life means that many can still be found on the road today, and maintenance parts are extremely common.

The simplicity of its design also allowed for great reliability, and they can easily last hundreds of thousands of miles. The 4.0 is also capable of making over 200 foot pounds of torque in a relatively compact size, which is a great combo for things like rock crawling. If you're not satisfied with stock power, engine upgrades can be found including exhaust, more aggressive camshafts, and supercharging kits.

The original Willys was desired by the military for its light weight and small proportions, which also made the vehicle popular with enthusiast drivers. By the 1980's the Jeep CJ had a length under thirteen feet, with a width of five feet. This means the vehicle can easily squeeze into canyon passes and between trees. Generally, it can go places that full-size trucks cannot. The short length also reduces the risk of scraping the back bumper while climbing a steep incline. A wheelbase of 93 inches also allowed the CJ to navigate sharper corners.

In 2023, the two-door version of the Wrangler has grown an extra foot long and foot wide. It's larger, but still plenty compact compared to other mid-size SUVs and full-size trucks on the road today. It also manages to pack modern innovations like air conditioning, satellite navigation, airbags, and rollover protection into that tight space.

There are plenty of Jeep purists out there that will only love the classic CJ, with the inline six, two doors, and a manual transmission. They scoff at anything modern, but modern technology comes with some undeniable benefits. When it comes to off-roading, electronic traction control has made drivers' lives a lot easier.

In 2023, computerized traction assistance can be found in most vehicles on the road, including every Jeep model. Chrysler implemented a brake-based traction control system into the Wrangler with the 2007 redesign. In these modern vehicles, the engine control and body control computer modules are constantly communicating with each other and relaying information on how the vehicle is handled.

In each wheel hub of the Jeep is a sensor that detects speed, and can accurately predict loss of traction. The vehicle's computer analyzes where the engine is sending power, and which wheels are losing traction. When it senses wheelspin, it applies braking force only to the side that is spinning. This means that the majority of torque gets sent out to the side with traction, and the vehicle can continue forward. If all wheels are spinning, the computer might also reduce the engine's power output to reign it into a more manageable state.

Modern Jeeps can also have separate driving modes for things like asphalt, gravel, sand, or snow. These computerized assists help make off-roading more accessible to enthusiasts at varying skill levels, and more people get to have fun on the trail.