# Are Ultra-Wide, Ultra-Low Aspect Ratio Tires the Next Big Thing?

by Kevin Rohlwing Editor and TIA Senior Vice President of Education and Technical Services 

# A lmost every component on a typical Class 8 tractor has changed significantly over the past decade. It’s finally reached a point where wrenches and hand-tools are almost useless without electronic diagnostic equipment. Who would have thought that modern diesel engine repair would be impossible without a computer and the proper software? From anti-lock brakes to automatic power dividers, technology has made almost every component on today’s truck dependent on microchips. One area that has seemed to escape the computer revolution from an operational standpoint is where the


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# Commercial Tire 

# s e rv i c e s e rv i c e

FEATURING

Are Ultra-Wide, Ultra-Low Aspect Ratio Tires the Next Big Thing? 29

Sometimes It’s the Little Things 32

What’s Your Opinion? 35

Photo courtesy of Alcoa and Bridgestone/Firestone

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# commercial tire service

rubber meets the road. Advanced rubber compounds and tread designs have undoubtedly improved both performance and mileage, yet the dependence on the correct amount of inflation pressure has not changed. Likewise, the tools and equipment required to service modern tire and wheel assemblies has basically remained the same for the last 20 to 30 years. Computerization has certainly played a role in the tire and retread manufacturing processes, but from a service perspective, the procedures are still the same. Unlike the automotive and light truck tire industry, where fitments change on an annual basis, the most popular medium radial truck tires continue to be the 11R22.5 and the 295/75R22.5 (275/80R22.5). These two sizes still comprise 55 percent of the original equipment market and 38 percent of replacements, as they have for past 10 years. One of the main reasons is that fleets demand standardization, so they are extremely reluctant to change. However, the new economy has forced the transportation industry to look outside the old model and explore new ways of cutting costs while improving performance. Fleets that carry high-bulk freight like paper towels and potato chips have turned to 17.5 and 19.5-inch tires, so they can increase the volume of the cargo space yet still carry the load. Since these tire sizes can require changes in the drive-train and braking systems, they are limited in their scope and acceptance. As a result, most companies are not able to retrofit all of their equipment to accommodate the smaller rim diameters, so the change must be made on an original equipment level. Standard wide base tires, like the 385/65R22.5 and the 445/65R22.5, have been popular in vocational fleets for years. Dump trucks and cement mixers can take advantage of the flotation properties in addition to the extra load-carrying capacity on the front axles. Once again, most of these fitments come directly from the factory, so the decision to go in that direction must be made in advance of a new equipment purchase.

A few years ago, the industry introduced a radically different tire and wheel design that allows fleets to take advantage of the benefits of replacing dual tires with a single tire. These new “ultra-wide low-profile” tires can be installed on practically any vehicle (if it has hub-piloted wheels) without the need to retrofit any axle components. With the same outside diameter as a 295/75R22.5 or 275/80R22.5, these tires do not require any recalibration of the speedometer or anti-lock brake system (if present). According to the manufacturers, fleets that utilize ultra-low aspect ratio tires will also experience improved fuel economy, a smoother ride and weight savings of around 500 pounds once dual tires are eliminated. From a service perspective, these new tire and wheel configurations are no different than any other wide-base tire. Currently, they are restricted to special aluminum wheels, but steel wheels are expected to be available in the near future (if they aren’t already). The demount, mount, inflation and installation procedures are also the same as any other tubeless radial truck tire on a wide-base hub-pilotedaluminum wheel, so the thousanddollar question is, “Will they ever replace the 295/75R22.5 and the 275/80R22.5, the most popular medium truck tire sizes in North
America?” The answer is—it depends. One of the first obstacles to overcome is the obvious difference in appearance. These ultra-wide, ultra-low profile tires are a radical departure from what the industry has grown accustomed to over the past few decades, so businesses that are historically resistant to change have to alter their ways of thinking. However, bulk haulers of gasoline and other liquids see the immediate advantages of the additional 500 lbs in carrying capacity and have led the way in retrofitting their tractors and trailers. According to reports from drivers, the ride improvements are noticeable with an increase in vehicle handling. Which brings up the second major issue; what happens when a tire goes flat? One of the advantages of dual tires is the ability to “limp” home, a seemingly impossible scenario with these new assemblies. Additionally, one would think that a flat tire would 

# ‘ ... the new economy has forced the transportation industry to look outside the old model and

explore new ways of cutting costs while improving performance.

# ’

‘ These new ’utra-wide

low-profile‘ tires can be

installed on practically any

vehicle (if it has hub-piloted

wheels) without the need to

retrofit any axle components.

# ’

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# commercial tire service

result in a drastic reduction in handling, causing the vehicle to lose control. Manufacturer tests have shown that the sudden loss of air in an ultra-wide, ultra-low profile tire does not have a dramatic effect on handling. In fact, one manufacturer even devised a special internal device that fills the air cavity to provide extra stability in the event of a flat tire. To summarize, losing the air in one of these tires does reduce the ability to “limp” home, but the effects on handling at highway speeds in those situations are minimal. Another topic that always comes up is mileage. It’s not uncommon for modern over-the-road drive tires to cross the magical 200,000-mile barrier, and early returns on the performance of ultra-wide, ultra-low profile tires indicate similar results. There’s also the issue of retreading and whether these new tires can deliver the same type of mileage that traditional dual drive tire retreads have enjoyed for years. Once again, manufacturer tests indicate that their retreadability and durability is comparable to dual drive tires. The final stumbling block is the availability of replacement tires when the need for emergency road service arises. While they aren’t as common as 295/75R22.5 or 275/80R22.5 tires, ultra-wide, ultra-low profile tires are readily available at truck stops and most dealerships that carry major brands. On the other hand, breakdowns in certain remote areas that require a replacement tire may result in a somewhat lengthy stay on the side of the road. On the surface, there appear to be very few negatives about making the switch to ultra-wide, ultra-low profile drive and trailer tires. The improved fuel mileage, smoother ride and weight savings should be enough for most fleets to give them a shot. If transportation companies can get past the radically different look and educate drivers to embrace the advantages, it’s possible that their popularity will continue to increase as time goes by. Will they ever replace the 295/75R22.5 or 275/80R22.5 as the most popular tire sizes in North America? That remains to be seen. Just remember that fleets once thought the 10.00-20 would always be the workhorse and tubeless radials were just a passing fad. And we all know how that turned out. ■ 

# ‘ The improved fuel mileage, smoother ride and weight savings

should be enough for most fleets to give them a shot. 

# ’

Photo courtesy of Peterbilt Motors Company and Bridgestone/Firestone