— Guide to the pros and cons —
With more and more manufacturers introducing 32-inch UTV tires, we’ve had to convert our long-term test UTVs so we could accurately test the new offerings. Very few UTVs come with 30-inch tires, and most are fitted with 27- to 29-inch rubber with very low ply ratings, so manufacturers can brag about low vehicle weight. With 32-inch tires being on the verge of replacing 30-inch tires as the new “normal,” let’s take a look at their benefits and drawbacks.
WHAT ARE 32-INCH ADVANTAGES?
Besides lightening our wallets, what do 32-inch tires do for us? First off, they increase ground clearance, which reduces damage to suspension components and skid-plate wear and tear. They also increase ride quality, as they roll over rocks and roots more easily, and increase traction by providing a larger contact patch. More sidewall provides more cushion for a better ride quality, although the trend is also moving towards more 15-inch rims, which reduces sidewall slightly. More sidewall means more flex for a better ride, especially if you run lower pressures. We love the new Kanati Terra Masters at 13 psi. They also look really cool.
WHAT ARE THE DISADVANTAGES?
Besides extra cost, they also add weight. More weight and greater leverage on the CVs, axles, bearings, diff gears and the driveline in general are concerns, but the greatest problem to overcome is CVT tuning. A car designed for 29-inch tires will not build revs properly with 32s, so an aftermarket CVT kit will be necessary for the UTV to run right.
Our long-term 2015 Polaris RZR XP 1000 has had many sets of 30-inch tires, and the first set of 32s were Fuel Grippers (February 2018) on 15-inch Fuel Anza beadlock rims. Next, we mounted a set of 32x10R15 GBC Terra Masters (March, 2018) on OMF 15-inch beadlock wheels. Both are 10-ply tires, so we put them on bathroom scales. The GBC/OMF combo weighs 56.8 pounds each, while the Fuels weigh 60.6 pounds each. The 30-inch Kanati Mongrels we took off of the XP1K weigh 52.4 pounds each, but part of that weight difference is eight-ply versus 10-ply.
With the 32-inch GBCs and Fuels, rpm was off by 400 rpm.
DALTON CORRECTS THE MATH
A call to Dale at Dalton Industries of Nova Scotia, Canada, set us on the path to more rpm. Dale sent UTV Action a Dalton clutch kit for the XP1K. This is a very impressive kit, because it allows tuning for tire size and weight in two ways. First, the helix has two ramps machined into it, and the more shallow ramp shifts slower and allows more rpm. Using the shallow ramp, we gained rpm to put us back at the 8200–8600 rpm optimum.
Second, the Dalton kit has new primary-clutch weights that allow fine-tuning without disassembly. The DUV P10XP/P10XP4 kit includes Dalton’s patented Quick Adjust flyweight system, which is really clever. Each weight is drilled and tapped almost all the way through, and the kit has a selection of M5 set screws (long and short) and three sets of rivets of varying weights, so overall weight can be fine-tuned without removing the primary every time you want to run a different tire or change altitude.
We installed the Dalton XP1K clutch kit per instructions and were very impressed with initial testing. With the proper revs back, overall performance was restored with proper acceleration and back-shifting under load. Belt slipping disappeared, so we don’t have to worry about the taller tires burning belts. It’s a well-spent $419. We’ll evaluate the Dalton XP1K clutch kit later, after we’ve played with different weights for varying conditions, tires and altitudes.
355 Vimy Road
Truro, Nova Scotia
B2N 4K2 Canada