Ranchers test performance of low-profile radials for a year .

The Broken O Ranch in Augusta, MT, recently served as a testing ground for a new Michelin agricultural tire. The company introduced the XM108 low-profile radial tire to the U.S. market more than a year ago.

Eighteen thousand acres of alfalfa and small grains are raised on the 135,000-acre ranch. It also supports a 4,500 cow-calf herd and 400 head of buffalo. The huge fleet of equipment required to keep up with this operation provided ample opportunity to test tire performance.

The test. Eleven 4-wd tractors form the backbone of the ranch's operating equipment. A set of eight XM108 radials was installed on one of the tractors - a 300-hp, 4-wd John Deere 8760 - in March 1998. The tire size was 650/65R42. The tires were replacements for the tractor's original Firestone 20.8R42 Radial All Traction 23 tires.

The ranch had been plagued by heavy spring rains, and tractors were having a difficult time plowing without getting stuck. The only operator who kept moving through the muddy conditions was Myron Huelle whose tractor was outfitted with the Michelin XM108s. In the same field where Huelle was working, an identical John Deere 8760 bogged down, and its plow sank to the frame.

Under "normal" conditions, the farmers would resort to a tracked vehicle to pull out the equipment. But to further test the XM108s, Huelle used his 8760 tractor. He pulled out the other tractor and plow and repeated this performance four times over the next four months.

The ranch has been using the Deere 8760 with Michelin XM108s in seeding applications 60 to 70% of the time. The remaining 30 to 40% of op-erating time is dedicated to plowing.

"Because the tractor doesn't get stuck in wet areas, we're working some ground that has never been broken before," says ranch manager Dan Freeman. "Plus, we're able to get into existing fields earlier to plow."

No slip. Freeman says that the Deere 8760 is routinely performing with virtually no slip in normal conditions and no more than 3% slip in the wettest working conditions.

Huelle says the tractor also has virtually no spin, which allows it to take full advantage of its horsepower. "The tires stay nice and clean even in the mud, and that really makes a big difference in the traction and pulling power," he says.

Better fuel consumption. Huelle adds that the lack of slip has provided a noticeable difference in fuel consumption. He estimates that he used to fill the tractor's fuel tank every 10 hours. With the Michelin XM108s, the tractor gets about four extra hours from every tank - a savings of approximately 40%.

Huelle also likes the comfort that the tire's radial construction provides. "You get a nice, smooth drive down the road, just like a car," he says.

Freeman projects that the XM108s will see about 1,000 hours of wear per year and is eager to compare their long-term performance with the Firestone 20.8R42 Radial All Traction 23 tires that previously outfitted the Deere 8760.

"I really like the XM108s because they give the tractor more power," Huelle says. "I'd fight if you threatened to take them away."

XM108 Michelin agricultural tire

Description: 65-series low-profile radial designed as a replacement for 80-series OEM tire. Fits on a standard rim.

Size: Full range of 19 sizes, from 16 to 42 in. in diameter.

Applications: 2-wd, mechanical front wheel assist and 4-wd tractors with 60 to 230 hp.

Also can be used as duals for 4-wd tractors with up to 425 hp.

Benefits: Offers improved performance without the added cost of new wheels. Fits on a standard wheel and operates at low air pressures for high flotation and reduced soil compaction.

Price range: $320 to $1,700

Contact: 888/552-1213 for the dealer nearest you