A diversified farm in eastern Washington struggled with accelerated wear of the traditional R-1 tires on its fleet of compact tractors, most of which spend hour after hour driving cover cropped row middles, farm roads and highways around the orchards, vineyards, hopyards and fields.

The farm manager called Mike Beckstrand, business development manager at Commercial Tire in Yakima, Washington, for advice. He asked about the tires he’d seen county mowing crews using on the road embankments around the area.

Hybrid Tires

Beckstrand steered the customer toward a new kind of tire design more like the mowing and maintenance crews that caught the farmer’s eye. Instead of the thick, curved lugs of a traditional R-1 tractor tire, the multiuse tires favored by highway maintenance crews have a dense tread pattern comprised of rectangular blocks organized in arcs. Those designs provide strong sidehill traction and clean out mud, but resist abrasion on roads and hard-packed soil much better than lugs. They are often called “hybrid” tires because they combine the blocks of commercial tires in a curved configuration like the lugs of traditional farm tires.

And as it happens, like hybrid plants and animals, the combination adds a boost in performance.

Beckstrand also brought in James Crouch, National Segment Manager—Agriculture and Forestry for Yokohama Off-Highway Tires America Inc., which manufactures hybrid tires that are extremely popular with highway maintenance crews around the world: the Alliance 550 Multiuse Radial and the Galaxy Garden Pro Radial.

“Farms doing a lot of orchard or vineyard work don’t necessarily need a ton of off-road traction that you’d need if you’re doing tillage, where a traditional lug bar would be better,” Crouch notes. “With this application, they really needed something more like a pickup truck tire because if you’re stripping it back, it looks and smells like a tractor, but a lot of the time it’s actually acting like a pickup truck, flying up and down the road hauling sprayers and things like that.”

Beckstrand and Crouch outfitted most the farm’s fleet of Kubota M-4s with 420/70R24 Alliance 550 or Galaxy Garden Pros on the rears and 300/70R20 Garden Pros on the fronts. In addition to providing the needed balance between traction and wear resistance, the radials’ tough industrial casings minimize heat build-up from long days and resist punctures from prunings and debris.

Meanwhile, the farm continues to spec R-1s for the tractors its crews use for tillage or high-clearance work, where the bar lugs provide extra traction in loose soil.

Lead-Lag: Getting it Right

Just as important as the switch to hybrid treads, says Beckstrand, was solving the growing problem of blown front-end transmissions on many of the farm’s compact mechanical front-wheel drive (MFWD) tractors.

“The farm first experimented with R-1 bias ply or pickup tires on the fronts and radial R-1 rears, and they were going through multiple front ends,” says Beckstrand. “Every time I walked through the shop, they had a line of tractors in here with the front ends torn out of them, so I always had in the back of my head that there was something wrong with the lead-lag. When I penciled it out, we found out that it was off by a couple percent, which causes more failures and more downtime on that equipment.”

Lead-lag is a mismatch in the proper size ratio between front and rear tires on an MFWD tractor. The transmission of every MFWD tractor is geared for a very specific ratio of tire circumferences—for instance, maintaining a 1.4:1 diameter ratio between the larger rear tires and the smaller front ones. That means for every revolution of the rear tire, the front tire rotates 1.4 times.

Deviating from that ratio creates the kind of lead-lag problem the farm crews encountered, and can stress the front end gearbox.

Lead-lag also accelerates tire wear and decreases fuel economy. If the front wheels on a MFWA tractor are too small, they run too fast, or lead, which can accelerate tread wear, increase slip, and cause a wide range of other issues. If the fronts are too large, they will lag, or run too slowly, causing a braking effect on the tractor and scrubbing the tread as the tractor pushes the tire across the surface. Lag can also bind the transmission and severely damage the drivetrain, notes Crouch.

“Lead-lag isn’t always just a problem of the wrong tire size,” he adds. “If you have extremely worn-down tires on one axle and brand-new tires on the other, you can create a lead-lag problem even when the tire sizes are correct on paper. That’s why it’s really worthwhile to work with your tire dealer when you’re replacing tractor tires.”

Time for a Change

The farm’s standard of success for in tires is a lower cost per hour of operation, and the switch to the hybrid Garden Pros and 550s delivered. Beckstrand did the math.

“We went from 1,500 hours on a set of tires to anywhere from 5,000 to 7,000,” he reports. “Every tractor’s a little bit different, every driver is a little but different, but for just an extra $100 or so, we still quadrupled—or, at minimum, tripled—the hours that they’re getting, so cost per hour is down quite a bit.”

It all illustrates that for many of today’s tractors, it’s time for a change in what we think of as an ideal farm tire, says Crouch.

“The traditional R-1 bar pattern has been out there for 100 years,” Crouch points out.

“The problem is that tractors do something dramatically different now than they did a hundred years ago. Road miles, spraying, pruning, mowing—I mean, even the compact tractor itself wasn’t a thing a hundred years ago. Now, you see such a huge variety of applications. Finally, the industry has reflected that by creating a bigger variety of farm tires, so that there are better options out there than that century-old bar pattern.

“Take advantage of that variety,” he advises. “It’s worth talking to your tire dealer about how you use your equipment to make sure you are running tires that are going to give you the best performance, return on investment, and protection for your tractor.”