Cooper Zeon XST Tires

The recently introduced Cooper Zeon XST targets the performance-minded Sport Truck enthusiast, who's more limited on budget than desire. After spending some time with the tire, we found it to be a great-looking tire, and given the very reasonable price point for the 255/55R18s, it's a good value. Here are the details.

Cooper says of its Zeon XST tread compound that it is specifically engineered to optimize all-around tire performance. Cooper applied some technology from its all-weather performance tires, which is basically comprised of a tread compound with good wet and dry traction that even allows some snow capability-enough, at least, to get it an M&S rating and put it on a high-performance carcass. Its spiral-wound nylon over-wrap inhibits tire growth at high speeds, a necessary aspect of a speed-rated performance tires. In addition, it's designed to run with quiet stealth by virtue of its varied number of shoulder elements, tuned to cancel noise.

To give you an idea of the performance benefit of the Coopers, we're comparing the tire's road noise and ride qualities to the OE tires on a 4.8L automatic '99 GMC Sierra with a 2/4 drop suspension from Hotchkis Performance. We'll forego the performance comparison between OE and the XSTs for obvious reasons. The OE replacement rolling stock combo of stamped-steel 16x7-inch wheels, with 5-inch backspacing, was wrapped with a two-ply polyester side-walled, two-ply steel and polyester P235/70R16 tubeless radial. The plus-two rolling stock upgrade consists of a set of Cooper Zeon XST P255/55R18 109H ultra-high-performance tire mounted on a set of forged aluminum Raceline Phat Excess 18x8-inch rims with 4-1/2-inch backspacing. Both sets were tested at the factory-recommended 35 psi of air pressure and driven over the same test-drive loop with all cornering and braking tests performed at the same site.

The visual inspection showed a normal amount of out-of-round, for both the stock rollers and the Cooper Zeon XSTs. We also checked body interference at max steering angles with the vehicle, while driving and at rest. Both sets of tires had no clearance issues at rest or driving, which is one of the benefits of a plus-two combination that has the same circumference as that of the OE unit. That also means gearing didn't change, and we didn't have to recalibrate the speedometer or install new rearend gears to compensate.

Since Cooper touts the quiet operation of the tire, we evaluated tire noise at various speeds on common road surfaces, as compared to the OE tire. At freeway speeds, OE tire noise wasn't an issue, since the wind noise was louder than any possible tire noise. On surfaces with some roughness, such as expansion joints or irregular patches, the OE replacement tires weren't noisy at all, even on older, worn pavement with gravel exposed from erosion.

The Cooper Zeon XST was slightly noisier than the OE at freeway speed, yet they were noticeably quieter than other high-performance tires with equally aggressive tread designs. Over expansion joints and other surface displacements, the tires generated more noise than OE, but in our judgment, that indicates increased sidewall and tread stiffness. That just comes with the territory of high-performance street tires that enhance cornering and overall handling.

In that regard, we found the Cooper Zeon XST a very sporting, agile, and responsive tire. The XSTs delivered good handling, grip, and load capacity, which is just what you need in a performance light-truck tire. The sidewalls and tread are stiffer, resulting in a tire with more feel through the wheel and frame, giving you a lot of confidence when driving hard. The truck is now far more surefooted compared to the stock tires, though a firm borderline harsh ride with the higher-rate springs and shocks of the lowered Hotchkis suspension is a factor to consider.