New-Generation Mud Tire
Mud-terrain tires have been around for decades, and most have adhered to a few similar patterns that worked well in the mud and in most off-road conditions but suffered on the street due to their off-road-biased design. But that was the old type of mud-terrain tires. Nowadays, companies are starting to hit hard with tires that have been developed with years of experience combined with the most advanced computer technology. And tires like the Pro Comp Xtreme Mud Terrain are starting to show up - tires designed to roll smoothly down the road, handle snow and ice like an all-terrain tire, and still perform in the dirt and mud.
We got a chance to try the Xtreme Mud Terrains in both 38-1/2- and 33-inch sizes on a 4WD truck and a 2WD truck to see how they'd work in all conditions.
The tread has a flatter tread face with single siping grooves through each tread lug. It 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.
Make/Model: Pro Comp Xtreme M/T
Size on Sidewall: (A) LT305/65R17, (B) 38.50x14.50R18
Load Range: E
Max Load: 3,525 lbs per tire
Tire Hardness: 67 on tire durometer
Tread Depth (in): 21/32
Number of Plies in Sidewall: Three (two radial polyester and one angled polyester)
Number of Plies in Tread: Six
Weight of Tire (lbs): (A) 58, (B) 91
Measured Diameter Unloaded (in): (A) 33-3/4, (B) 38
Measured Width Unloaded (in): (A) 12, (B) 13-1/4
Measured Tread Width (in): (A) 10, (B) 11-1/2
Mounted on: (A) 17x8.5 Pro Comp Alloy Series 8128 wheels, (B) 18x9 Pro Comp Alloy Series 8089 wheels
Available Tire Heights (in): 31 to 38-1/2
Available Wheel Fitments: 15- to 22-inch-diameter wheels
This tire did work well in the mud, but keeping it road-worthy was a main concern since Pro Comp knows very well that most of these tires will spend the majority of their lives on the road. That road worth dictates a low void-ratio spacing, and when the mud gets really bad, you'd be better off with a higher void ratio like some of the more extreme bias-ply tires adorn. The particular mud we were in seemed to keep gumming up the tread and leave us spinning with a bit less bite than we would want. We would still get enough traction to push us through, but it wasn't as much as we would've liked.
For such an aggressive tire, the Xtreme Mud Terrains are exceptional on the road. The noise from the tread was minimal, and they rolled smoothly on the asphalt. No flat spotting was noticed, even after leaving them deflated overnight and driving on them the next morning while still cold. Cornering with these tires (with what little cornering we could do in our test trucks) 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.
Sand is the one place these tires fell a little short. Sand is a tricky off-road condition, as the rules that apply in other types of off-roading don't necessarily apply here. Most people will tell you that the absolute best sand tire is one with very little tread (or a sand paddle if you have the horsepower to push them). The Xtreme Mud Terrain wanted to keep digging and did not stay on top of the sand where you need to stay afloat. Besides that, our test Tacoma had a very hard time getting any sidewall bulge out of these 33-inch tires, even at only 11 psi on 17-inch Pro Comp Alloy Series 8128 wheels. (In their defense, they were load range E tires on our light pickup, but we expected at least a little bulge.)