Fleets seem to run hot and cold on alignment and balance. Some swear by them, while others see them as unnecessary expenses. Discussions with fleet maintenance managers suggest that many who do balance tires balance only steer tires, and then only once when new. Fleets that do not balance believe that today’s top radial tires are manufactured to high enough standards that they should not need to be balanced if they are mounted and installed properly.
As for alignment, the most common refrain we hear is from fleets is to align the truck before putting it into service as part of the pre-delivery inspection, and then align only as needed throughout its life.
Combined, the prevailing thinking would seem to suggest fleets are willing to perform these services only if there’s an obvious need, like premature tire wear or driver complaints about ride and handling.
Two views on balancing
Lloyd Hair, maintenance director at Pennsylvania-based heavy-hauler Keen Transport, routinely balances steer tires and will do so again if he gets driver complaints about ride or handling. He does not balance drive or trailer tires.
“I’ll use as much as 16 ounces of weight to balance a tire,” he says. “If it needs more than that, I’ll deflate the tire, break the bead and rotate the tire 180 degrees on the rim and try it again. That more often than not does the trick. If that doesn’t work, I send the tire back to the manufacturer.”
When he gets a driver complaint about vibration, he doesn’t automatically pull the wheels off and balance them. He investigates the complaint.
“If the tires are wearing properly and they aren’t damaged, a vibration is usually a sign that something else is wrong,” he says. “If you assume it’s the tire and put a weight on it or use some balancing compound, you might be masking a driveline problem, such as a failing U-joint.”
Fred Staugh, vice president of maintenance at Iowa-based CRST, does not balance his tires. He spends a little more time ensuring they are mounted properly. Staugh believes that unless there’s a defect in the tire, if the tire and wheel assembly is round and running true, it won’t need balancing.
“When I say round, I’m talking 60- or 90-thousandths of an inch of tolerance on radial and lateral runout as measured with a dial indicator,” he says. “If you have that inspection process down and you use those guidelines, there’s no reason on Earth to balance a steer tire.”
Staugh believes you can eliminate the need to balance tires just by installing them properly and then checking them for runout and a heavy spot while on the vehicle. He says rims should be inspected with a runout gauge before the tire is mounted, and they should be within the manufacturer’s tolerance. The mounted tire should be checked for concentric mounting by verifying the gap between the rim flange and the bead seating ring is the same all around the tire and on both sides of the tire.
“Even if you know you’re putting a round tire on a round wheel, you still have to check after it’s installed for its high spot,” cautions Staugh. “With the high spot marked, place it at the 12 o’clock position on the hub where gravity will pull the wheel down onto the hub pilots, creating a natural low spot. The two will cancel each other out. It doesn’t get any better than that.”
Guidelines for these inspection and mounting procedures can be found in the ATA’s Technology & Maintenance Council Recommended Practice library. Look for RP 214D.
Align when needed
Your tires will tell you whether or not the vehicle is going straight down the road. Staugh says tires should be examined at every preventive maintenance interval for telltale signs of alignment-related wear, such as feathering, or excess wear on opposite shoulders of the steer tires.
“You can’t shove a tire down the road at any kind of an angle other than straight ahead and not get some kind of wear pattern that will indicate the truck is not going straight down the road,” he says.
Hair, too, is constantly on the lookout for wear patterns that suggest a vehicle-related problem, such as alignment.
“I align when new and usually again at between 250,000-300,000 miles,” he says. “I will always pull a truck in for an alignment when I see sign of unusual wear as well.”
Both Hair and Staugh agree that thrust angle is more often the culprit with alignment than front-end problems.
Both also regularly check their trailers for alignment. It’s a simple check: measuring from the kingpin to the front axle, and then from the front axle to the rear. It only takes a few minutes to check and it can save many 32nds of an inch of trailer rubber.
Balance and alignment have long been touted as tire saving measures, although maybe a little tough to quantify — but how about fuel savings? TMC’s S.11 Energy Conservation Study Group recently updated RP 1111, Relationships Between Truck/Trailer Components and Fuel Economy. It says that “tire balance across 18 tires on a tractor-trailer combination has been documented to save as much as 2.2% SAE J1326/RP 1102 Type II fuel testing at two different facilities.”
Getting all your tires headed in the same direction isn’t going to hurt fuel economy either. But there’s also tire life improvements to be had, and since the most fuel efficient part of a tire’s life cycle is the latter half, when not try to extend that life as long as possible? It won’t bankrupt you to throw some balancing compound into a few sets of trailer tires to see what sort of life increase or better fuel mileage you get.