Pressure points

What began with a product engineered for military applications has evolved into a family of Roadranger tire-management products that meets different trucking requirements, recounts Jim Beverly, Dana's chief engineer-advanced chassis control systems. Dana's first tire-management product, dubbed Central Tire Inflation System (CTIS) by military types, was engineered specifically to increase the mobility

What began with a product engineered for military applications has evolved into a family of Roadranger tire-management products that meets different trucking requirements, “recounts Jim Beverly, Dana's chief engineer-advanced chassis control systems.

“Dana's first tire-management product, dubbed “Central Tire Inflation System” (CTIS) by military types, was engineered specifically to increase the mobility of U.S. Army trucks by automatically controlling tire pressure. “Despite its name,” Beverly says, “its primary feature is its ability to deflate tires enough to increase the ‘footprint’ of the tire enough to improve off-road traction. Essentially, the tire becomes longer.”

Although it may seem as if that action would hurt tire life, according to Beverly, speed is a factor. “Many fear deflating for mobility will damage the tire. But when you reduce vehicle speed, you can safely reduce tire pressure too.”

He says the military actually started using the system in tandem with all-wheel drive (AWD) to gain “ultimate mobility.” AWD, Beverly explains, is great for “traversing objects” but CTIS works best for moving a vehicle over soft soil.

With that in mind, Dana developed a commercial version of CTIS marketed by Roadranger called Dana Tire Pressure Control System (TPCS). It's for vocational fleets faced with slogging through tough off-road conditions — but not necessarily with climbing over things.

“Vocational truckers used to spec AWD as their best solution to gain mobility,” says Beverly. “But our tire-based product has virtually eliminated the AWD market in soft-soil areas. For these truckers, there's almost universal acceptance of TPCS. Many of these buyers can't afford both and find CTIS is more affordable than AWD.”

Beverly says Dana is working on a TPCS product that would fit light-truck applications and would perhaps complement AWD. “OEMs are looking at this for government contracts, such as the Border Patrol, as well as for consumer markets.”

Military and off-road, and potentially light trucks, can use tire control systems to gain mobility. But for on-highway commercial vehicles, tire pressure systems are strictly maintenance-oriented, like the Dana Tire Maintenance System (TMS) marketed by Roadranger.

“Tire pressure maintenance is crucial over the road,” Beverly says. “It's generally accepted in the industry that tire failures account for over 50% of road failures. Those failures cost money, not to mention the downtime they produce. Pressure itself is subject to the laws of physics — for every 10-degree drop in ambient temperature, there's 1 psi drop in inflation pressure. Fleets have to stay on top of that to protect their tires and stay on schedule.”

Beverly describes Dana's TMS as an active “smart” tire-maintenance system controlled by a microprocessor. “Unlike a regulator-based system, ours does not put continuous pressure on the seals and lines, which can cause wear,” he says. “It automatically checks each tire at startup and then every 10 minutes, inflating them only as needed.”

He says the programmable system can be set to warn only at a specific threshold (typically 10%) below optimum pressure.

According to Beverly Dana engineered the system to perform in the real world of trucking. “That's why TMS has a sealed wheel end,” he advises.

“Our system uses the axle tube to vent externally,” he explains. “Since we don't vent through the hubcap, water can't get in if the trailer is positioned in a dock area that's under water or if the trailer is cleaned under high-pressure water.”

As a computerized system, Beverly points out, TMS can be set up with data links for transmitting tire information via satellite-based communication systems to advise of tire problems or schedule needed maintenance to avoid damaging tire casing.

One reason Beverly offers for using a “smart” tire management system is simple but compelling: “When a driver drops a trailer off, it is out of sight — and out of mind.”

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