First it was the Pro Comp All Terrain that received the revamp, and the resulting Xtreme All Terrain proved itself to be a winner. Now Pro Comp has decided to take a crack at its Mud Terrain. The new Xtreme Mud Terrain is everything that the last six years of research (since the original Mud Terrain) has led up to, and we think Pro Comp has done a fine job launching itself into this new era of daily driveable but super aggressive tires. The new tread design is reminiscent of a Toyo Open Country M/T or a Cooper Discoverer and, like those two tires, has a flatter tread face with single-siping grooves through each tread lug. The tread reaches to the outside widths of the tire and down onto the sidewall for added puncture protection and to enhance traction. The carcass underneath the rubber you see is comprised of Pro Comp's Armor-Tek3 construction: two radial polyester plies met with one angled polyester ply.
Mud
When we heard the name Xtreme Mud Terrain, we might have gotten our hopes a little too high. This tire did work well in the mud, but the particular mud we were in seemed to keep gumming up the tread and leaving us spinning with a bit less bite than we would want. We still got enough traction to push us through, but it wasn't as much as we would've liked. This tire is no TSL Bogger, and we shouldn't have expected it to work as such. This is a newer-school mud-terrain radial, made for today's trucks that have to be able to handle 80 mph on the freeways and interstates if necessary. For a radial tire that can be comfortably driven every day, this tire was awesome.
Rocks
This is where the Xtreme Mud Terrains shined. In fact, Pro Comp should have called these Xtreme Rock Terrains. The tires had a thick sidewall that you could definitely feel, but with enough air out of them, they would conform around edges and get the traction we were looking for. We ran the tires at 15 psi in rocks and mud on our 18-inch Xtreme Alloy 8089 wheels, but next time would go a bit lower with the pressure, especially if we were running a smaller-diameter wheel and more sidewall. Nevertheless these tires still climbed up the rocks we wanted and hung by just a couple tread lugs without letting us slip in some situations. The lugs twisted and conformed to the rocks very well, no doubt thanks to the single siping line through each tread lug.
Highway
Wow, did these tires ride nicely! The noise from the tread was minimal, and they rolled smoothly on the asphalt. There was very little pull from side to side, even with an 11 1/2-inch width. Cornering with these tires (with what little cornering we could do in our test truck) was not bad either, with the flat tread face and extended shoulder lugs keeping this tire flat on the ground and inhibiting it from rolling pressure too much onto one side of the tire.
Overall Impressions
We'd put these tires on our rockcrawler, trail machine, or our daily driver. Overall, the Pro Comp Xtreme Mud Terrain was a champ at, ironically, everything except deep mud running, which it was still very good at. This tire drove excellently on the road, and even displaced water in some rain we drove in. It ate up rocks like a fat kid eats cake, and the mud running done with this tire was still pretty darned good. The tread rubber hardness came in at a 67 on the tire durometer (on the hard side), making us believe it would be a long-lasting, aggressive tire that we will be getting some good miles out of-something very important in this era of rising tire cost and disposal fees.
Make and Model: Pro Comp Xtreme M/T
Size on Sidewall: 38.50x14.50R18
Load Range: E
Tire Hardness: 67 on tire durometer
Tread Depth (in): 21/32
Number of Plies in Sidewall: Three (two radial polyester, one angled polyester)
Number of Plies in Tread: Six
Weight of Tire (lb): 91
Measured Dia. Unloaded (in): 38
Measured Width Unloaded (in): 13 1/4
Measured Tread Width (in): 11 1/2
Mounted On: Pro Comp Xtreme 18x9 Alloy Series 8089 wheels
Available Tire Heights (in): 31-38 1/2
Available Wheel Fitments : 15- to 22-inch-diameter wheels