A while back, Mickey Thompson brought outtwo new tires: the Baja ATZ Radial SLT and the Baja MTZ Radial SLT. Unfortunately, due to time constraints and availability, we were only able to test the ATZ at the time (June '05). Well, this time around we're finally getting a crack at the MTZ. And just to be clear, these are the SLT (Specialty Light Truck) versions. Models of the ATZ and MTZ in "traditional sizes" are different tread patterns altogether. The MTZ (SLT) is an aggressive mud-terrain tire with large voids in between the tread lugs with self-cleaning blocks to keep the tread empty for maximum bite. The tread blocks come out into the sidewall for increased traction and good curb protection (at least here in Los Angeles). Advanced radial construction was used to build the tire to ensure a smooth highway ride and longer tread life without sacrificing off-roadability.
These tires performed excellently in the mud. We dipped them into some sloppy goop and churned them up a whole bunch, and they came out the other side of the pit clean. The fact that they cleaned themselves out so well was a real advantage in the mud we were running in. The tires were deflated to around 15 psi on our fullsize Blazer and had pretty good flotation while spinning the tires.
We hit some rockcrawling out in the desert and proceeded to spin the tires, heat them up, crawl on up, and get a real feel for how well the tread would grip rock faces. Again the tires gripped the dry granite well, and with 15 pounds of pressure we were getting all the sidewall flex we would expect, but we might take them down to 10 pounds the next time out to get a little more flex. Though we liked them all right in the rocks, we did burn off a fair amount of tread for only a few obstacles.
Highway ride was decent on these tires. They were smooth, rolled well down the road, and did not track too much. We were actually waiting to see if these tires would track and pull into inconsistencies in the pavement, but they did pretty well. When we tested the ATZ SLT tires, we found that the extreme amount of rubber touching the ground (being an all-terrain) would grab almost everything on the pavement and pull the truck around a little bit. Since these tires had higher void ratios and a larger tread lug to squirm on, the MTZ did not pull as much. Unfortunately these are not the quietest tires in the lineup, but they are not as loud as some other older mud-terrain designs available to the public. It was nothing near the noise of a Swamper, but it was definitely no all-terrain.
The tread design is nothing fancy and very straightforward. We're into that kind of thing where the tread design was more focused on how well it would work instead of how good it looked to the public. The tire made a little more noise than we wanted, but it did perform excellently off-road. Unfortunately we got very little time on rainy or icy roads with this tire, so we cannot give you our opinions as to how they'd work in those conditions. But the tires do feature some siping across the large tread lugs, which should improve traction in slick conditions over a solid tread lug. We would probably mount these tires on a truck like our premudder K5. It already has a spool and a big-block, so tread wear and noise are negligible. And though that truck drives itself back and forth to the trails, its main purpose is as an off-road toy.
Make and Model: Mickey Thompson/Baja MTZ Radial SLT
Size on Sidewall: 37x13.50R18LT M+S
Load Range: D
Tire Hardness: 66 on tire durometer
Tread Depth (in): 21/32
Number of Plies in Sidewall: Three
Number of Plies in Tread: Six
Weight of Tire (lb): 86
Measured Dia. Unloaded (in): 36 1/2
Measured Width Unloaded (in): 13 1/4
Measured Tread Width (in): 11
Mounted On: Mickey Thompson 18x10 Classic II wheels
Available Tire Heights (in): 33-38
Available Wheel Fitments: 15- to 20-inch-diameter wheels