Visually, an "extreme mud terrain" may inspire images of a tire similar to a motocross tread, with a few knobs poking out of a carcass with an immense void ratio. Thankfully, the new Pro Comp is nothing like the name implies but rather a relatively mild-treaded mud tire-or an aggressive all-terrain, if you will-that is even quite at home on pavement.
These 285/75R16s came mounted and balanced on 16x8 Pro Comp 1059 wheels, a 357-pound package overall with lug nuts, center caps, and shipping pallet included. There weren't many weights on the wheels, proving that the 10-segment molds used to make the new M/T helped create a true-running tire. But we naturally couldn't resist running one on the Hunter GSP 9700 balancer just to check, verifying the quality of the job.
Expecting some sound effects from the 18/32-inch-deep M/T tread, it was a pleasant surprise to learn that this Pro Comp is far from noisy, but definitely audible. Still, it's quiet enough that after a few weeks, we didn't always notice the sound. It made sense then that this M/T also had a very low rolling resistance for a mud tire, and its load transition characteristics appear good, promising a long tread life. With its two steel plies and a nylon cap, the Pro Comp was relatively smooth over roadway irregularities, and cornering was on par with a good all-terrain. Without any tendencies to track from grooves in the pavement and stable and predictable handling in general, the Pro Comp M/T is certainly a tire that's very much livable on pavement.
As most any mud-terrain tire, this M/T wanted to dig down a bit, but the looser the surface, the better the 8.9-inch-wide tread worked. On one trail, we got disappointed when the Pro Comp wouldn't crawl up a hill we expected this tire to do fine on, instead digging and slipping sideways a bit, and at one point the vehicle came to a complete stop. The tires did find traction and we drove out, and it was our embarrassment when we realized that while the hubs were locked, we'd somehow neglected to engage the front axle lever on the Atlas transfer case. Oops. Chalk one up for the Pro Comps.
So how does the Pro Comp do in mud? We don't know. Doing most of the tire testing under controlled circumstances in very familiar areas and with the same vehicle year after year, we can get very good repeatability. This way-with the trails and test vehicle being identical-the tires become the only unknown which then makes it possible to judge the tires without interference from the other variables. Weather can naturally influence the results and some tires' performance increases with the moisture content of the dirt, while others do better when it's dry. In SoCal, where the vast majority of the testing is done, this means that it's almost always dry. This doesn't much matter with all-terrains and milder treads, but prevents tires such as the Pro Comp Xtreme M/T the chance to show off. So our best guess, based on the design of the Pro Comp's tread and its built-in features, is that this tire would work a lot better in mud than the average all-terrain and not quite as well as a typical, more aggressive mud tire. Those who have driven this new M/T in mud agree with our assessment.
Tire: Pro Comp Xtreme M/T
Load range: D
Max load (lb @ psi): 3,305 @ 65
Sidewall: 3-ply polyester
Tread: 3-ply polyester, 2-ply steel, 1-ply nylon
Approved rim width (in): 7.5-9.5 (8)
Tread depth (in): 18/32
Tread width (in): 8.9
Section width (in): 11.3
Overall diameter (in): 33.1
Static loaded radius (in): 15.6
Revolutions per mile: 646
Weight (lb): 56
Test vehicle: 6,300-pound K-5 Blazer