A few months back we brought you a sneak peek of the new Roctane radial tire from STI. That was a massive piece of rubber at 30 inches tall. It was so big, we had to make modifications to the fenders on our RZR just to get them to fit without a lift kit. Well, STI does offer the Roctane in some more down-to-earth sizing, and recently we were able to spend some serious torture-test time with them.
On this go-around, we chose to test 28×10-14s on all four corners of our RZR XP Jagged X. This machine comes stock with 26×12 Maxxis Bighorns. Cars like this RZR 4, Wildcat 4 and soon-to-be-released Maverick 4 do well in most wide-open situations but fall short in others. With such a long wheelbase, these machines get high-centered more than a two-seater does. So to improve upon the already-great Jagged X car, new, taller tires would hopefully be a solution.
The Roctane is sort of a cross between an ITP Blackwater and a Maxxis Bighorn. It has an eight-ply rating, deep lugs that wrap around to the sidewall and is non-directional. This pattern is available in a size range from 25 inches all the way up to 32 inches for 12- and 14-inch rims. A massive rim guard helps keep the tire on and keeps rocks from damaging your wheels. Weight is average for this size tire, at right under 30 pounds. The STI brand is actually owned by huge tire distributor MTA, so you know your dealer either stocks them or can get them in a matter of hours. Companies like PureOffRoad.com list this size Roctane for $150 each.
The sizing we chose worked out perfect. We mounted the new meats on a set of STI HD1 machined wheels. The 28s do not rub under normal trail conditions. We only had them rub on the right front once when we dropped off a steep rock ledge with the steering wheel slightly turned. With the help of power steering, the wider front tires didn’t hinder any movement. In fact, they helped the front of the car grip the ground and turn much better than with the stock tires.
On hardpacked conditions, the tires were smooth and provided plenty of traction for stopping or acceleration. They didn’t wander or hunt. In the sand, it was more of the same. Floatation was good, and the tires stayed exactly where we pointed them. And out of the sand, we pointed them right at the sharpest stuff we could find. Bounce was minimal, and feedback through the steering wheel was consistent. On the smoother, rocky trails, the tires absolutely gripped like glue. We could air down from 15 to 5 psi and claw up and over anything. After a 100-mile test, we didn’t even have a hint of a puncture and could hardly see wear marks.
The STI Roctane is a great all-around tire from a growing company. We expect to see a tire like the Roctane make its way onto some new machines as standard equipment in the near future—they are that good. Check out more of what they have to offer at www.stitireandwheel.com.