40" STRONG: COOPER’S DISCOVERER STT PROS
“…the Coopers stayed on course without weaving or bobbing, despite being tasked with rolling on what was arguably the bumpiest road in the country…”
The 40” tire market has grown substantially and we like to think that 40” are the new 35”. There are only a handful of recognizable brands that offer an aggressive tread in this size, and we had a recent opportunity to put a set of Cooper Discoverer STT Pros to the test – and test them we did.
To truly assess the performance of the Cooper STT Pros, we chose to drive across the U.S. from Toronto, Ontario, to Moab, UT, in some of the worst possible weather, wheel some of the most epic trails, and then drive all the way back home. So it’s worth mentioning that this is not your typical tire review, and these are not your typical tires.
What better way is there to honestly evaluate the performance of a tire than to hum them across the country, and then spend a few days running challenging trails? We drove more than 3,380 km (2,100 mi), through rain, sleet, slush and snow. We aired them right down, wheeled on some of Moab’s most iconic trails, and drove home exhausted – with nothing but memories and the wind behind us. Spending 30 hours behind the wheel is enough to drive anyone mad. What’s even worse is driving that distance on a poor set of tires.
For us, there are a few factors that contribute to a tire worth seriously considering including performance, price and appearance. We’ll be honest. How our tires look matter to us. The lug pattern on these tires is aggressive with sidewall lugs based on dinosaur bones. Fortunately, these tires don’t sound like a
T-Rex chugging down the highway. In fact, for such an aggressive lug pattern, they spin surprisingly quiet.
Road noise is a common concern with large tires. One thing we can’t afford is sacrificing road manners for lug patterns. With these Cooper STT Pros, we didn’t have to sacrifice anything. They have a unique 3-2 tread pattern, which is intended to reduce road noise and it works. We rely on our rigs to not only perform in the harshest conditions off-road, but also to drive our families safely home from soccer practices and trips to Costco. The Discoverer is a good looking and even better performing, reliable tire.
During our drive on the highways from Toronto to Chicago, the STT’s did surprisingly well. They tracked straight and we were even able to balance all five 40” tires. We quickly realized that 39 psi was the magic number for highway driving, which gave us the least amount of lug tread feedback. The tires did catch road crown, but at 84 inches wheel-towheel you’d be hard pressed to find a tire that doesn’t chase a little.
Through the flats of Iowa, with headwinds of nearly 72 km/h (45 mph) and side gusts blowing us nearly into the other lane, these Coopers gave us the confidence to keep on trucking. In the sleet of Nebraska, the Coopers stayed on course without weaving or bobbing, despite being tasked with rolling on what we thought was the bumpiest road in the U.S.
In the Colorado Rockies and up the infamous Vail Pass mountain range with cars and transport trucks strewn about like our kid’s dirty clothes, we consistently braked and anticipated being forced off the road. Yes, there were times when our tires slipped and slid, but the road was sheer ice and even a good pair of hockey skates would have struggled. However, the huge 40” M/T-rated tires did grip the road when descending and provided exactly the right amount of consistency to safely navigate the massive grades as we hammered down through the mountains and on into Utah.
Once in Moab, with the tires mounted on bead-lock rims, we quickly aired down to 6 to 8 psi without concern. That was until we were told the trailhead to Hells Revenge was a few miles out of town, down winding asphalt canyon roads. Initially we took it easy, slowing into corners and accelerating up to 48 kph (30 mph).
As time went on, we realized the STT Pros were just warming up, and towards the end of our trip we were cruising at 120 to 129 kph (75 to 80 mph) and hugging corners without concern. Several times our sidewalls could be