Six months ago we wrapped our wheels with a set of Cooper Discoverer STT Pro mud-terrain tires. Since then they have logged about 2,800 miles of dirt, mud, rocks, and pavement. It is time for a follow-up long-term report for our tire testing series after our first tire rotation since they were mounted. Around town and on the trail lots of onlookers compliment the aggressive looks of the tire and ask about how well they perform. Here’s what I have to say about them after some decent seat time.
Any test of a mud-terrain tire of course has to include some mud, and we spent some time in the Utah desert after about a week of consistent rain. Low-lying areas of trail were filled with water and silty mud pits that were perfect for testing these new treads. Efforts were made to locate every soupy spot along the way. The STT Pros kept digging and sustained forward momentum no matter what we threw at them. Steering control was always maintained, which was a good indicator that the lugs were clearing the mud as they rotated. When tires clog with mud they tend to become like drag slicks; you will lose some ability to steer and forward progress may be impeded as well.
Cooper has engineered the STT Pro mud-terrain tire to be just that—a mud tire. If we look at some of the finer details of the tread design it becomes evident how much utilitarian thinking went into this tire. There are relief groves cut into the front and back faces of the side lugs, which allow mud to be released from the tread voids. The ridges in the valleys of the treads are anti-stone bars to prevent rocks from being lodged in the tread voids.
While we would prefer to be four-wheeling five days a week, the reality is that we are rolling down they highway at 60 mph on our way to and from work, around town, or on the way to the trailhead. The tires are made from a softer rubber compound to increase the grip to the road and the trail, especially in wet and slick conditions. With that soft compound it can be expected to have slightly faster wear on the tread, but we are very happy with the observations so far on wear. Thanks to the 3-2 alternating center lugs, road noise was also kept to a minimum.
Moab trails are known for the excellent traction that the sandstone provides, but if you’ve ever been to Moab in the wet season, then you know why they call it slickrock! Some wet sand on the rocks definitely makes for a slippery day on the trail. There was a need for a little more wheel speed on the steep climbs and careful tire placement on technical obstacles, but all in all the Cooper STT Pros took it all in stride. As winter approaches and the snow starts to fall, we will have more things to talk about in our next and final update. Stay tuned!