The Low-Down On Wide-Based Tires

Wide, low-profile tires are the single-tire replacement for a dual pair, sized to provide exactly the same rolling radius.

Mark Putz
Associate Editor

      We're a lot further along than many would have thought," said Don Pelley, Michelin's X-One ultra-low-profile expert. Launched in late 2000, the wide-based, ultra-low-profile tire has been a big hit with the vocational and regional fleets, he says. But it's also made its mark with owner-operators. "There are a lot of teams where the husband is the driver and the wife is the chief financial officer — and she really understands cost-per-mile exactly," noted Pelley.
      These two extremes point up the ultra-low-profile tires' big pluses: improved fuel consumption and lighter weight, saving as much as 1,000 pounds per truck.
      The wide, low-profile tires are the single-tire replacement for a dual pair, sized to provide exactly the same rolling radius so that a dual pair of the popular 275 80R225 tires can be replaced by a single 445 50R22.5 on a special matching 14 x 22.5 wheel. On a tractor trailer, eight sets of duals are replaced by eight wide singles.
      Pelley says the early enthusiasm for the product was expressed in the number of retrofits early in the program. When the tire was initially available from Freightliner exclusively, retrofit sales ran about equal with X-One tires/wheels on new equipment. Now Michelin has made that even easier by cutting a deal with Alcoa, where the tires are available from Michelin dealers already mounted in a package with the special wheels. This makes it easier for fleets to retrofit. Also, the X-One is also available in three different sizes and is optional at all the tractor and trailer OEMs.
      At Bridgestone, where the Greatec ultra-low-profile has been displayed at a number of trade shows and fleet trials are under way, there has been concerted efforts to develop the Aircept, an in-tire safety bladder. This additional component of the wide-tire package has been demanded by European users of ultra-low tires. There, concerns for the stability of a 4x2 tractor when a tire goes flat led to the development of an "assistant inner ring interceptor" or Aircept.
      The Aircept system begins to expand if tire pressure drops below a specified level. By the time a total loss of pressure occurs, the Aircept unit has expanded to fill the entire interior of the tire, supporting the load. The Aircept system operates in conjunction with a tire pressure monitor that alerts the driver to the loss of air pressure, while the Aircept unit allows the driver to stop and change the tire.
      Greatec radials offer better fuel economy, increased payload and more space inside vehicles. With half as many sidewalls flexing and because a Greatec tire and rim weighs less than two conventional tires and rims, rolling resistance is much less, significantly decreasing fuel consumption. The weight savings also allows extra payload within the vehicle's total legal capacity.
      In addition, the Greatec single-tire configuration is narrower than a dual configuration, conserving space under large vehicles. That makes more space available for aisles and seating, for example, in buses.
      Goodyear currently offers a wide-based tire — the 435/50R22.5 L Marathon LH — and is eyeing the market for the release of more products in the future. According to Al Cohn, marketing director for commercial tires, "We are studying retreading issues and looking for ways to offer customers a better product." That said, Goodyear officials noted that they didn't want to tout any coming products too far ahead of the release date. "We don't want to create interest in a product until our customers actually get a shot at getting their hands on it."

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