Everybody knows how important it is to keep your truck’s tires inflated to the right pressure: safety, stopping distance, fuel efficiency, operating costs, and tire life are all directly related to running on properly pressurized tires. And they’re all good reasons why Bendix and the rest of the trucking industry remind everybody about tire pressure at every turn.
One aspect of tire inflation that we haven’t talked about nearly as much is the importance of keeping both tires on a dual-tire wheel-end inflated to the same psi. This should get more attention, because running mismatched tires on a dual-tire assembly is an easy way to destroy two tires and risk safety.
Two identical wheels mounted on the same axle wheel-end will, by the rules of science, rotate at the same rate as the axle. Attach a couple identically inflated tires to those wheels, and all is right. Things begin to go awry if one of those tires has lower air pressure, which changes the tire’s shape and properties – and reduces its diameter.
When that happens, you have two, different-sized tires on your dual-tire assembly. Here’s why that’s bad. The larger tire will bear more than its share of the load, which will ultimately cause the tire to run hotter and may lead to sidewall damage or a potential blowout. The smaller tire will drag – because of the difference in diameter and revolutions per mile between the two tires – resulting in highly accelerated wear due to the tread being scrubbed.
How much pressure differential matters? Industry data indicates that it can be as little as 5 psi – with both over- and underinflation coming into play.
For obvious reasons, we’re big fans of tire pressure monitoring systems (TPMS) that communicate real-time tire pressure information and alerts – and in some cases, tire temperature as well – to the driver and technicians. And for the reasons discussed above, one of the recent additions we’ve made to the SmarTire® TPMS by Bendix CVS is a programmable alert when a set of dual tires exceeds a set deviation in pressure.
It’s all about keeping drivers informed on the road, and technicians informed in the shop: The more you know, the safer your truck runs.
Technical and industry insight from OUR experts.