By Mike Millar
Photos by George Hunter

With the introduction of the Xterrain, Procomp Tires has hit another home run. They've created a tire that is both more aggressive and quieter than most others in its class. Looking at its paddle-like tread pattern, you'd assume that this tire would be a real howler on the street but the exact opposite is the case. It's a very nice handling street tire that sacrifices none of the off-road performance you'd expect from this tread. How did they do it? They used a directional tread pattern that allowed their engineers to focus on optimizing the wind travel in a single direction. Adjusting the wind travel allowed them to reduce the noise. The significance of this development is that it now makes a good performing mud tire a feasible option for the fourwheelers who use their 4x4's as a daily driver.

Besides being quieter, the Xterrain also differs from most other mud tires by having tread lugs that go up the sidewall to provide additional grip when aired down as well as improved sidewall protection. Most sidewall damage I've seen occurs in that shoulder area where the sidewall meets the tread blocks so the Xterrain's tread design should result in an even more dependable tire.

Puncture resistance comes in the form of Dualguard [tm] polyester body plies. The tire's body contains thick, two-ply polyester plies combined with a blend of dual side wall rubber that provides maximum puncture resistance with total flexibility when using lower air pressure off road without excessive heat build up. To improve tire longevity and performance on and off the pavement, the Xterrain's huge tread lugs contain full length and full depth sipes.

Our test tires are 35x12.5R15 mounted on the Procomp Rockcrawlers wheels which have served me well for many years with my previous Procomp Mud Terrains. Like the Mud Terrains, the Xterrains worked extremely well with the Rockcrawler wheels. Running at pressures as low as 8 psi, I never once lost air pressure. For that matter, I never once suffered a tire puncture, either.

We spent most of our time testing these tires in mud and on rock- and root-strewn trails. Many of those days included healthy downpours of rain. As many of you know, wet, sharp rocks are a sure bet for sliced sidewalls but the Xterrains took it all in stride. My spare tire is still sitting on my tire rack, wondering if it'll ever get the chance to taste dirt.

The ability to reliably run at low pressures meant that the Xterrains could lay a nice fat foot print on the terrain resulting in less wheelspin, better performance, and less trail damage. I think these tires would be especially effective for lighter vehicles that may have difficulty flattening out the carcass of a stiffer bias ply tire.

On the subject of bias ply tires, as I've mentioned in the past, several of my fourwheeling buddies run bias plies. Except for extremely deep mud (I'm talking about three feet deep or more), the Xterrains were able to keep up with the bias plies. If you want the ultimate in off-road performance, bias ply tires are still the best choice. But if you want to drive your truck on a daily basis, or more than 50km on the highway in order to reach the trailhead, then it's pretty hard to beat the versatility of the Xterrains.

In summary, I've been very impressed with the Xterrain's performance. Enough so that I'd like to try out the new 37" Xterrains as well.

The Xterrain and the Procomp Mud Terrain. Notice the more aggressive sidewall of the Xterrain.	Balancing was done by North Shore Off-road Centre.	A comparison of the more traditional Mud Terrain on the right, versus the very aggressive Xterrain.
Trail performance was very impressive.	Notice how well the sidewall flexes.	Mud was not a problem.
This is a shot after we finally got out of a particularly horrible mud trail. It ended up claiming my transmission a few weeks later but the Procomps turned in a great performance.	As long as the tire's on the ground, it'll grab.	Pro Comp Tires www.procomptires.com Email: Info@ProCompTires.com For Dealership and Export Information Contact: Transamerican Wholesale: 1-800-548-6454, Fax 1-310-900-5580 or Explorer Competition Products: 1-619-670-5222, Fax 1-619-670-5960