Lose Air, Gain Traction: KMC Machete Crawl Beadlock Review [Video]
The cheapest off-road performance mod you’ll ever do to your 4x4 is letting air out of the tires. Dropping the air pressure increases the tire’s contact patch and allows it conform to the terrain more easily. This equates not only to increased traction, but a much smoother ride. For light ‘wheeling, most 4x4s can get away with dropping the tire pressure into the teens. However, for more extreme off-road conditions, you’ll actually want to drop your tires into the single digits.
The issue with dropping your 4x4's air pressure into single-digit territory has more to do with the limitations of the wheel rather than the tire. At single digit pressure, the tire’s bead can easily become dislodged from the wheel, scenario that can result in serious damage to your rig. The solution? Beadlocks wheels.
Why Beadlocks?
A beadlock wheel works just as the name indicates, by “locking” the bead of the tire to the wheel. This is most commonly achieved by placing the outside bead of the tire between a ring that is bolted to the wheel. By bolting the bead between the two surfaces, you effectively lock the bead in place. Since the bead is now being secured in place by the clamping ring, you can deflate the tire into the single digit range without fear of the tire easily coming off of the wheel.
Recently, we picked up a set of KMC XD229 Machete Crawl beadlocks for our 2013 Jeep Wrangler Unlimited Rubicon project. Our goal for moving to the wheel was twofold. First, we needed a little more backspacing to prevent our 37x12.50R17 Nitto Ridge Grapplers from contacting our suspension components under articulation. Secondly, we knew that if we could get our load-range D tire’s pressure a little lower off-road, we could improve the ride and traction potential. While the video above walks you through our initial impressions and assembly, we’re breaking down the details in the article below.
The KMC XD229 is comprised of cast aluminum and uses an external aluminum ring to “lock” the outer tire bead to the wheel. One of our favorite features on the wheel are the relief holes machined into the ring. These prevent debris and water from building up inside of the wheel.
The XD229 is offered in a 17x9, which is ideal for most 12.50 to 14.50-inch wide tires. Here, you can see the deep groove the outer bead sits in. To ensure the tire can’t easily break free, the outer ring is attached using 24 Allen-head bolts.
Dual Valve Stems
KMC understood that if you’re opting for a beadlock wheel, you’ll likely be adjusting air pressures more frequently. So, they made it a bit easier by equipping the wheel with two valve stems. This makes airing down a quick and easy affair as you can use one to deflate the tire, while monitoring the pressure with the other.
Popular wheel bolt patterns, such as our JK’s 5-on-5, along with custom patterns, are available. You can also opt for a machined or satin-black wheel finish.
All of the XD229 beadlocks come with 3.50 inches of backspacing. This is one of the features that drew us to the wheel as we needed this to keep the tires from contacting our suspension components during articulation. The added width also helps with stability on the trail.
Ideal Air Pressure
Off-road, we’ve found 5 psi to work great for our needs out back, and between 5 and 8 psi does the trick up front. At this tire range, we are able to get the 37x12.50R17 Nitto Ridge Grapplers to easily conform to the terrain, which has only increased our love for the tire off-road.
We’ve been accustomed to running our Grapplers around 12-15 psi, so we were extremely curious to see just how big of a difference dropping them down to 5 psi would be. While it may not seem like a big difference in numbers, it was something we felt immediately. Not only did the tires grip better, but the ride on the trail was exponentially smoother.
Off-Road Only?
Something to consider is that the wheels are listed as off-road only. Since there are currently no specific regulations or testing parameters in place for beadlock wheels of this type, they do not fall under the category of DOT compliant. Yes, there are many other “off-road only” mods that people use on the street, and that doesn’t mean they are unsafe. If Ultra4 Champion Loren Healy can abuse this style of wheel on the race track, it’s safe to say they can handle your daily commute.
That being said, the KMC beadlocks will require a bolt check from time to time. We like to give ours a re-torque after every ‘wheeling trip and oil change. To do so safely, we recommend jacking the tire off of the ground and removing the air completely.
For us, the performance benefits of the beadlock wheel have absolutely made a positive difference in our JK. While not every off-road adventure will require single-digit pressure, the fact that we can now do so in confidence is peace of mind that equates to money well spent.
