A little over a year ago, we began our long-term test of a set of Cooper Discoverer STT Pro mud-terrain tires. For most, the excitement of getting new tires is also met with a feeling of uncertainty. Will they meet your needs and expectations? Will they whine so loud on the highway that you can't hear yourself think? Do they clog up with debris? To alleviate some of that anxiety for you, and to answer at least some of your questions, we performed a three-installment long-term road test on the STT Pro tires, taking them through as many terrain situations as possible.
This is the third and final report on the STT Pros rolling under our 1979 Jeep CJ-7 (weighing in right about 4,600 pounds). First, let's look back at the two first reports for some background. In the first report (fourwheeler.com/how-to/wheels-tires/1807-long-term-tire-test-cooper-stt-pro), we provided all the tech on the tire and our first impressions. After another six months of sustained and observational seat time, we gave you the second round of the long-term test on the Coopers (fourwheeler.com/how-to/wheels-tires/1811-cooper-discoverer-stt-pro-take-2). For the final wrap-up and overall impressions after a year of rolling on these Discoverer STT Pro tires, read on.
The Cooper Discoverer STT Pro is one good looking tire with nice curb appeal. The aggressive tread pattern design adds a mean, meaty look to any Jeep—no matter what size you choose to run. We also really dig the big, bold white lettering that is still standard. Some off-road tires are abandoning white lettering all together, which is a shame. There's something classic about white lettering that just looks rad rolling through town on a classic Jeep. When given the choice, whitewalls out!
Good off-road tires should also work well around town. These have seen about 5,500 miles of pavement, and during that time these tires have been rotated twice. The tread is wearing evenly and holding up well to off-road abuse, with no chunking. Mud-terrains tend to be a little loud rolling down the blacktop compared to all-terrain tires, but the road noise was barely noticeable on the Coopers when the hardtop was on the Jeep. It did become more apparent once we lost the top during warmer weather. The little bit of noise we experienced wasn't a big deal and was easily covered up with some radio jams.
Tread design is more than just good looks. The STT Pro lives up to its reputation off pavement. Smaller lugs and the engineered tread pattern allow the tire body to flex easily, grappling around obstacles for increased footprint and traction. The tires are at 10 psi in this photo. On the red rocks and desert sands of southern Utah, we were very impressed with how well the Coopers performed. Even in the spring-monsoon desert mud, the tread never packed in—thanks to the several different mud-release features designed into the tread.
Let's flash back to the second day the tires were mounted on the Jeep. Rocky terrain can be tough on tires, and we were reminded of that when we found this sidewall gash at the end of the trail day. Thanks to the Armor-Tek3 technology built into the sidewalls of the Discoverer STT Pro, the tire never leaked any air. We even continued to drive on it for the rest of the week of heavy wheeling as an added test. It was eventually replaced, but still sits in the garage holding its air a year later.
There's no wheeling like snow wheeling! There was over 3 feet of snow on the mountains when it came time to go find a Christmas tree in southern Idaho. In the deep snow the Coopers were pretty decent. The lugs really helped bite and pack their way through the snow. Even when buried to the frame, like in this shot, we weren't stuck! Snow-covered pavement driving is a totally different field of play though. The STT Pro tread scored in the average part of the scale. Siping in the tire tread made handling manageable with some delicate driver finesse. Although we personally have driven many a winter on mud-terrain-style tires, generally big lugs just don't make good snow tires. In the same sense that standard tires for cars are not good snow tires either. Cautious driving habits should always be utilized on snowy roads, regardless of the tires on your Jeep.
The Coopers have carried this Jeep to a lot of familiar places in a year, and to an even greater number of new adventures. At the end of the day, we would happily run them again. The on-road drivability is great, and their off-road dynamics and traction abilities continued to impress. It's a great all-round tire for a Jeep daily driver that also sees some trail time.