On the merit of visual impact alone, there is no comparison between an R-1W radial tractor tire and its more subdued cousin, the R-1. But industry experts say bigger isn't always better.
“The appeal of the R-1W is that its broader, deeper lugs make the tire look bigger, beefier, and therefore — many people assume — better,” notes Dave Weed, applications engineer for Goodyear Ag Tires. “But this is a classic case where looks can be deceiving. In many situations in North America, and for many producers, the R-1 tire is going to give better performance in the field.”
In fact, Weed says the R-1W was designed and manufactured initially for use in northern Europe. “Producers in Europe typically operate in situations where the ground is much wetter,” he explains. “The soils are older and heavier and the level of drainage is often poor compared to fields in North America. These operators need a tire with deeper, more widely spaced lugs that will pull through the muck and the mud. This perceived operating advantage in wet conditions, plus the tire's more aggressive look, has been winning the R-1W a growing number of farmer converts in North America.”
From 1998 through last year, the number of John Deere 8000 and 8010 series tractors ordered with R-1W tires increased from 9 to 18%. “This trend appears to be in proportion with the types of soils found in North America,” says Shan Prendergast, John Deere 8020 series tractor product manager. “However, if the orders for R-1W tires continue to increase, our concern is that a significant percentage of customers may be choosing the wrong tire for the types of soils that many of them have.”
Weed concurs: “Unlike northern Europe, the largest percentage of crop ground in North America features well-drained, firm soils. The R-1 is designed to excel in these. The tires have a narrower lug spacing, which puts more biting edges in the tire's footprint. This creates more shearing of the soil, more traction and torque, and more pulling power for the tractor.
“The R-1W is going to perform better in mucky, heavy-clay soils, where the wider lug spacing allows the tire to better clean itself and the deeper tread provides more digging action needed to pull the tractor through,” Weed says.
In a comparative analysis, Goodyear studied the pulling capacity of various brands of R-1 and R-1W tires in both tilled and untilled soil conditions typical throughout much of North America. The evaluation showed that R-1 tires, independent of brand or design, yielded 11% more pulling capacity than R-1W tires in tilled soils, and 10% more pulling capacity on untilled ground.
Weed says the study shows that, unless you're running consistently on heavy, sticky, wet soils, the R-1 is going to be a better tire choice than the beefier-looking R-1W. “It's a win-win situation,” Weed says. “The R-1 costs less up front, performs better and gives a better ride. And you'll avoid the shudder effect that the R-1Ws tend to produce at slow speeds.”
Although versatile, the R-1 is not a one-size-fits-all solution. “We offer many tire options,” Prendergast says. “Our goal isn't to sell one type of tire over another, only to help farmers select the type of tire that is best for them.” He recommends discussing specific needs with tire retailers and tractor dealers.
There are many types of tires and just as many different ways to use them. Firestone's HF-3, for example, is a logger flotation tire, yet it is often used effectively as a scraper-pulling tire. Some rules of thumb to consider: Although an H-3 is better at floating, an H-2 is better at carrying heavy loads. And although an R-1 usually pulls better, an R-1W, in addition to handling muck, should wear longer on the road by virtue of its longer lugs.
Firestone Agricultural Tires senior engineer Jay Wheeler says that a wider lug means less engagement with the soil and therefore less overall traction. “We make R-1, R-1W and many other tires,” he says. “But generally, the deeper lug is not justified for most farmers around here, except in extreme cases like pulling a scraper, or in the case of rice/cane tires where the lug is much taller and has a slightly wider base. That type of lug is subject to more flexing.
“There's also the issue of tread bar angle,” Wheeler continues. “Firestone has built a lot of tires with 23° angle treads for North America. But we also make some 45° angle treads, which are popular in Europe.”
Europe versus the U.S.
Why such a big difference in treads between countries? Ken Brodbeck, manager of export sales for Firestone, helps manufacturers in different parts of the world choose the right types of tires for their customers. He looks at typical field conditions as well as how farmers are using their tractors. He points out a few differences between Europe and the U.S.
“With many different radial designs, various treads and metric sizing, it can rapidly get confusing for farmers,” Brodbeck says. “It's probably easier to point out the differences in farming. Europeans, for example, tend to use their tractors more like trucks, pulling loads at high speeds down the road. But they'll also tend to get into wetter fields. This makes the 45° tread more popular in Europe. But the 23° tread tends to work better for farmers in North America. Americans need the extra pulling power to pull wider implements through firmer soils.”
In the complex world of tractor tires, there are no easy answers to most questions. Because every farmer's situation is somewhat different, the best choices typically come on the advice of a knowledgeable sales rep or dealer. But more tire choices and technology mean even a good dealer can get confused without proper training. Major tire manufacturers have all realized a growing need to train the people who sell tires to farmers.
Michelin product marketing manager Brad Harrison points out that training at the tire retail level, as well as training for tractor dealers, is becoming an increasingly important part of the ag tire business.
“It takes a lot of knowledge for a dealer to match the customer with the appropriate product and then give good service,” Harrison says. “Dealers should be asking a lot of questions. And if they don't, the farmer should. What tire works best for the tractor's horsepower, weight, ballast, implements, speed and transport requirements? And the big question — What tire pressure should you use?”
In addition to live classroom sessions, Michelin sets up tractor dealers and tire retailers with an online “tractor tire master course.” More than 1,000 people from around the world have taken the eight-hour course.
Among other things, the course teaches basic tire math, tire physics, terminology, warranty information and tire trivia. For example, the industry's technical term for a tire's basic structure? The carcass. And Michelin's definition of an R-1W drive tire? It has a lug that is 25 to 40% higher than that of an R1 tire and open lug design, and it is used in general and wet farming conditions (“W” stands for wet).