Some fleet mangers have embraced wide single tires, others remain skeptical. So let’s take a look at the issues surrounding replacing duals with one tire. According to Pressure Systems International, the manufacturer of the Meritor Tire Inflation System by PSI, there are two main advantages: weight savings and fuel efficiency.
Weight savings can add up to as much as 1,300 lbs., depending on whether the fleet is replacing both the drive and trailer tires and whether or not it is using them with aluminum wheels rather than steel.
Fuel economy is the other obvious advantage because of the reduced rolling resistance of only one tire and one wheel. There are other advantages, which include:
• Easier maintenance (no inside duals to worry about);
• Eliminate dual matching concerns;
• Improved brake cooling; and
• Improved, softer ride because the tire is so wide the vehicle is not susceptible to the normal road rutting condition that occurs over time.
Know the difference
It is important to understand that one (wide base) 445/50R22.5 is NOT double two 11R22.5 tires. A conventional trailer tire size is 11R22.5 and the most common wide base tire size is 445/50R22.5. So using two 11R22.5 tires gives an overall tire footprint of 124 sq. inches. Using one 445/50R22.5 has a footprint of 111 sq. inches (10% less contact area).
The wide base tire is doing more “work” than two duals, which results in the tire being more sensitive to running overloaded and under-inflated. Also, remember that heat will become a big issue if the wide base tire is not properly inflated. Running even 10% under inflation will lead to premature tire removal because of irregular wear and tire durability.
Most fleets that are running these wide base tires use an automatic tire inflation system because maintaining proper inflation of the 445/50R22.5 is so critical. Also, when running single tires, if you experience a puncture, there is NO limp-home capability unless your trailer is equipped with a tire inflation system.
Fuel economy is critical for most fleets today and using the new wide base tires will improve fuel economy, but by how much? The answer is—it depends. PSI said it has seen reported numbers from 1% to 4% increased fuel economy, but the company said there are many variables that can affect vehicle fuel economy. Drivers, roads, loads, vehicle make and model all contribute to this equation.
Running a serious fuel test on your specific fleet operating conditions is the only way to determine if the new wide base tire is right for that fleet’s application.
For fleets that haul loads that gross out in weight, such as grain and produce haulers, the additional weight savings of using wide base tires can increase payload and daily revenues. For these types of fleets, using wide base tires is likely a no-brainer, PSI added.
