When the Commercial Vehicle Safety Alliance (CVSA) conducted their 2024 North American blitz, more than 13,500 commercial vehicles were put out of service for a variety of violations.
It’s not surprising that 21% were related to tires. Every year since 2018, tire violations have taken the number two spot on the CVSA’s list of vehicle violations. Clearly, tire safety is an issue that can stand to be improved.
Andrew Stacey is a national fleet safety loss control specialist for Aviva Risk Management Solutions. He visits commercial and corporate fleets across the country and says drivers and fleet managers can do a better job at assessing tire conditions during and between pre-trip inspections.
He offered his best advice on what to look for—and why.
Loose lug nuts
One of the leading causes of tire separation in tractor trailers are loose lug nuts or ones that haven’t been adequately retorqued after being put on.
“After a tire change, the driver should drive 50-60km and bring the truck back to the shop for a quick check that nothing has come loose. It’s mandatory that tires are retorqued every time,” said Stacey.
Drivers should also check the lug nuts on every tire during pre-trip inspections. Signs of a loose lug nut include metal shavings from metal-on-metal chafing or signs of rust.
Low grease and oil in wheel hubs
Stacey advises drivers pay close attention to the cap located in the center of the hub of each tire. “I used to carry a paper clip or safety pin with me to poke the hole so it can breathe.”
He also recommends making sure there’s adequate hub oil as part of a pre-trip inspection.
“You want to pop the cap off unless you can read through sight glass. If it’s a brand new hub, you might be able to read it. Besides checking the level, you’ll know it’s low if you see oil markings on the side of the tire. That’s a sign that an oil system has started to fail or you’ve got a leaky seal. This can contaminate the brakes and cause the hub to overheat and if that happens too much it could lead to wheel separation.”
Another red flag for drivers to look for is excessive heat coming off the hubs, which a driver can check by placing their hands near the hubs after completing a leg. “You need to investigate further to see if you’re burning up your hub,” said Stacey.
Incorrect tire pressure
It’s critical to ensure the tire is inflated to the manufacturer’s specifications since underinflation and overinflation are equally problematic.
“If you’ve got a tire that’s low and you’re putting weight on it, you don’t have proper contact with the surface. This can cause heat to build up and the tire can blow,” he said.
“And, even though you won’t get placed out of service for overinflated tires, it’ll wear them out quickly and cost you on your fuel.”
During a pre-trip inspection, Stacey suggests following the best practice of striking each tire with a mallet and listening for a good, solid ring. The tone should sound the same on each tire.
“This is not something you’re going to find by kicking or slapping the tire with your hands or kicking it with a boot. You’ve got to have enough weight behind it to get that sound.
“If you hear a dull tone or a thud, you’ve got an air pressure problem.”
Tread depth
All drivers should be looking at the tread depth during pre-trip inspections.
“When the tread depth goes down in a tire, you’re going to see little ridges or square bumps between the treads. That’s the wear bar. As the tire wears down, it will become flush with the wear bar and that’s an indication that the tire needs to be replaced right away,” said Stacey.
At the end of every inspection, he recommends rolling the truck ahead two or three feet and looking at the treads again. “There could be flat spots or wear in one area of a tire and not on others.”
Excessive load
It’s dangerous and hard on a vehicle to drive with a load beyond the recommended weight limit. Tires will often take the brunt of an overloaded trailer, blowing out while on the road.
“It’s important for drivers to check their bills of lading for the weight they’re hauling. Always take it across a public scale to ensure it matches,” said Stacey.
“If you’re overweight on an axle group, you can take your trailer tires and move them up or back to redistribute weight, if you have to.”
He says all drivers should be trained on weights and dimensions so they understand how much weight is appropriate for the axle groupings of each trailer they haul.
Wrong or mismatched tires
Some trucking companies may send out trailers with different types of tires that don't match, which can lead to uneven wear patterns. This can be risky and increase the chances of a tire blowing out while on the road.
“If I put a summer tire on the outside but a beefy winter tire on the inside, one tire will have more tread depth than the other and take more of the load. It’ll heat up and could cause a tire blow out.”
If a driver sees an obvious mismatch in a pre-trip inspection, Stacey advises running it by the mechanic. “And if you do have a blowout on the side of the road and the mechanic doesn’t have a match, you can get it back to the shop but then it needs to be changed immediately.”
Bulges and cracks
The first part of looking at tire conditions during a pre-trip inspection involves a simple visual scan for clear damage to the tires, such as bulges and cracks.
“You want to make sure the tire looks healthy and isn’t weathered or cracked because it’s been sitting forever. Check to see if you can see steel cords, which are a clear indication that a tire is worn down, and should never be taken on the road,” said Stacey.
“You should also look at the sidewall for any deep cuts or obvious sidewall damage.”
Cupping
Cupping (also known as "scalloping") refers to irregular, uneven wear on the tire's tread that results in a series of high and low points, giving the tread a wavy or scalloped appearance. This type of damage often indicates underlying mechanical or maintenance issues rather than normal wear and tear.
“Run your hand across the tire's surface to feel for dips, bumps, or a scalloped texture that may not be easily visible,” said Stacey.
“And pay attention to unusual vibrations while driving, especially at higher speeds. Cupping often leads to noticeable shaking or a rough ride.”
Invest in an effective tire maintenance protocol
Stacey says many larger companies have a contract with a tire company that sends a licenced tire technician to a yard once or twice a day to do inspections on tires.
This shouldn’t replace a driver’s responsibility for assessing the conditions of tires before every trip. “Drivers are the last line of defence,” he said.
“Post-trip inspections are also critical. Walk around the unit to check for leaking hubs, excessive heat or punctures from the trip. You could even do a mallet check again. Then you can let the mechanic know of any issues so they can be fixed before the next trip.”
Looking for more information on tire safety?
Aviva Risk Management Fleet Safety is available to answer your questions. Please reach out to Aviva’s Commercial Fleet Consultants.