So the only remedy is a different tire: a 16-ply load range H tire inflated to 115 to 120 psi. But reducing the load on steer tires is impractical, and the load and inflation tables for most standard and low-profile 22.5-inch tires don’t allow for 13,200-pound loads. To solve the problem, you could reduce the load on the tire or inflate it more. Or viewed from another angle, the tires may be underinflated by 15 to 20 psi. If those axles are loaded, those tires could be running 1,000 or 1,500 pounds each over their rated maximum.” Yet, the tires on the axle at 100 psi are rated for no more than 11-5 or 11-6. Often, those axles are loaded up to pretty close to that rating, so we know the tires are supporting close to 13,000 pounds or more. “The manufacturer knows the front end of the truck is heavy, so they use an axle capable of carrying the weight. “The heavy steer axle is there for a reason,” Beckett says. He sees a shocking number of trucks coming through his shops with low-pro 22.5 LRG tires inflated to 100 psi on even 13,200-pound axles. Mike Beckett of MD Alignment in Des Moines, Iowa, gets a close look at trucks and their tires every day. If their steer-axle loads are running at or close to the axle rating, the tires may be technically in run-flat condition.
In cases where the operator may not be aware of the tire rating, they may still be inflating their LRG tires to only 100 psi. The 13-2 axle adds a new dimension to tire selection.
#Average tire psi drivers#
Watch for drivers who deflate steer tires to 90 psi thinking it will provide a smoother ride. While actual steer-axle loads may not have reached that high in all cases, there are certainly some situations where loads come very close to that.”
#Average tire psi install#
“Some manufacturers now install 13,200-pound steer axles in order to accommodate loads over 12,000 pounds. “ Steer axle loads have increased over the years, going beyond 12,000 pounds in some cases,” Decker adds. And more recently, EPA emissions regulations added a bunch of emissions hardware to engines and chassis, adding another 1,000 pounds or so to the truck. Set-back steer axles shifted a larger percentage of weight forward, thus increasing steer-axle loads. "Even if you're inflating to the recommended pressure, you're leaving yourself no margin." -Curtis Decker, Continental Tire North Americaīack when they were still popular, long-nose conventional steer-axle loads seldom exceeded 12,000 pounds in normal on-highway service, so 100-psi inflation pressure was adequate.
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