Pressure Control

A guide to inflation systems.


The trucking industry should be thankful for the multitude of on-board tire inflation equipment choices that are available to today's fleet managers. That's because one undisputed fact remains evident— when tires are not properly inflated, fleets lose money.

Yes, inflation related problems are pushing down profits, and pressing down on all of us. Fuel economy suffers. Tire expenses increase. Downtime mounts. Margins shrink.

So the obvious question is: which system works best to better fuel consumption, improve tire life, increase uptime and boost margins?

To address these needs, fleets have a variety of technologies and products from which to choose. The primary options include inflate/deflate systems, inflate/maintenance systems, and monitor systems.

Despite its name, the primary feature of an inflate/deflate system is its ability to deflate (as opposed to inflate) tires to increase the tire footprint enough to improve off-road traction in soft soil conditions. Dana's experience with this technology began about 25 years ago, when the U.S. armed forces began specifying the Central Tire Inflation System (CTIS) to increase the mobility of Army trucks. Successes with the military eventually brought about the introduction of a commercial version, typically utilized by vocational users such as mixers and loggers.

Building upon that experience, Dana in 2004 introduced the Spicer TIMS (Tire Inflation and Monitor System), which is a system that automatically monitors and maintains proper tire pressure inflation. This inflate/maintenance system measures actual tire inflation pressure and not just flow, and notifies the vehicle operator when tire pressure falls below a pre-determined level— typically set to 10 percent below the desired cold-tire pressure setting. This is significant in that the driver is only notified when the system detects a low pressure condition that requires corrective action, not just for minor tire inflation needs at start-up. The reasoning for this— why warn a driver every time minor pressure inflation adjustments are required?

Also with this technology, seals and lines are non-pressurized when not inflating. That was done to virtually eliminate the likelihood of premature seal failures that were common with continuous pressurization systems.

Another available option is to implement a system that provides real-time tire pressure and temperature monitoring. This system works on the road, not just when passing through a stationary gate-reader or when someone is using a hand-held device. The technology can communicate to off-board communications systems, sending important real-time pressure and temperature data to provide proactive maintenance scheduling as required. A record-keeping function provides convenient access to tire pressure events.

It is important to note here that the temperature monitoring feature measures temperatures which directly impact proper operating tire pressures. In doing so, it automatically compensates for temperature fluctuations, ensuring proper inflation regardless of tire temperature.

Next year, with the new emission standards going into effect, the importance of selecting the correct tire inflation system would appear to be even more important than it is today. Our industry will be faced with a host of additional challenges in terms of initial vehicle costs, fuel efficiency losses, maintenance costs, and more. So the present would certainly seem like a prudent time to begin finding ways to reduce costs.

When trailer tires are properly inflated, your typical fleet can generate savings in excess of $1,000 per year due to fuel economy improvements, extended tread life, increased up-time, and the avoidance of costs associated with tire blowouts. According to a study conducted by the Technology and Maintenance Council of the American Trucking Association, tires that are under-inflated by as little as 10 percent will cause fuel degradation penalties of roughly 0.5 percent. That same report notes that tread life will be shortened by as much as 16 percent.

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