A tire evaluation doesn't end once the test tires are mounted. To determine which tire truly delivers the lowest cost per mile, fleets need to follow each tire throughout its entire service life. That means tracking where every tire is installed, documenting tread wear and inflation at regular intervals, monitoring fuel economy and maintenance history, and accounting for retread performance. A quality evaluation takes time, but the data that comes from it can lead to better purchasing decisions and lower operating costs.

Tracking the test tires

Each tire under evaluation should be tracked through its complete lifecycle. That requires identifying the vehicles participating in the test as well as the individual tires. It’s easy enough to flag the test trucks. That can all be noted in the maintenance schedules and service records. But individual tires can be a bit trickier.

They are round and black, and do not have unique serial numbers. If one fails and is removed at the roadside, it should be noted in the records. [Pro tip: Make sure the driver brings the carcass back to the shop for analysis.]

You’ll need a robust tracking strategy, advised Kevin Rohlwing, chief technical officer for the Tire Industry Association (TIA).

“The tire identification number (TIN), also known as the DOT Code, can be used, but it is not unique to a single tire since it identifies every tire that was manufactured in that particular week and year,” he told Fleet Maintenance. “Some tires have RFID tags with a unique identifier, which can make the process a lot easier, but a reader is required to capture the information.”

Other possibilities include tracking the tire through the TPMS platform, though that generally works only on trailer tires. Aperia’s Halo Connect system also monitors and tracks drive tires.

Tire branding is another possibility, but Rohlwing doesn’t recommend it.

“It’s still out there, but not as widespread as it used to be,” he says. “There can be problems with the brand being too deep and damaging the casings.”

Stickers or other notices can also be applied to the truck to alert the driver and maintenance staff to the ongoing tire evaluation, cautioning them not to perform tire repairs or replacements without approval from a manager.

Dealers and suppliers can help with this. Take advantage of their expertise.

The numbers that matter

On the operational front, the in-service evaluation should include, at a minimum, tread depth, inflation pressure, and a visual inspection of the tire.

Irregular treadwear patterns are usually caused by something other than the tire itself, though some tires may be more sensitive to certain types of wear. Observations taken at regular intervals will indicate when the first signs of irregular wear begin to appear. Compare those mileages against other tires under evaluation to determine whether it’s a trend across all the tires of a particular make and model or just a one-off unique to a certain truck or trailer.

“During inspections, tread wear, inflation pressure, cuts, chips, tears, and irregular wear should be thoroughly documented,” Kidd said. “Keeping detailed notes on each tire helps spot red flags before they arise and mitigate costly repairs and additional downtime.”

“Even small cuts that expose ply material can lead to big problems down the road,” added Rohlwing. “Those should be replaced and either repaired or retreaded before the casing is destroyed.”

Depending on the type of service and wheel position being tested, Bridgestone recommends the following inspection intervals:

• Steer position every 90 days
• Drive position every 180 days for tandem axles and every 90 days for single axles
• Trailer position every 180 days
• Waste applications, all positions every 60 days
• Urban/P&D applications, all positions every 60 days

Another method is to record tread depth and mileage every time a tractor or trailer is serviced.

“Even if it’s something as simple as a windshield wiper replacement, all of the tread depths are recorded along with the mileage,” offered Rohlwing. “As long as the vehicle is in the maintenance facility, it only takes a few extra minutes to record the information and check or adjust the inflation pressure.”

A word of caution on inflation pressure: You won’t get reliable readings if the truck has just come in off the road and the tires are warm. Tracking pressure loss over time is an important part of the evaluation, so “take your pressure readings when the tires are cold,” Rohlwing reminded.

Avoid skewing the results

There’s more than one way to ruin a tire evaluation. These are long-term projects that can take a year or longer. Tread wear likely won’t even appear on the tire within the first few months.

You don’t want to baby those tires, but nor do you want to beat them up. You want to evaluate them on trucks and with drivers that best reflect the state of the fleet. You also don’t want to over-maintain them. Treat them as any other tire in the fleet and stick as close as possible to your regular inflation and inspection routines.

“If you’re only checking air pressure on the tires being evaluated, it will skew the results,” Rohlwing said. “Inflation pressure maintenance is a year-round component for every tire program, and it has a direct effect on cost-per-mile—positive or negative. Don’t treat the test tires any differently.”

Pick a handful of trucks at early- to mid-life that are mechanically sound. Align them and replace the shock absorbers before the evaluation begins. This eliminates two of the major sources of irregular tire wear.

“The greatest challenge is minimizing differences between the test groups to ensure the results are not influenced by outside variables,” Yokohama's Clauer said.

If you’re evaluating the tires for fuel efficiency, extra care should be taken to avoid missing a fill-up. Even a few hundred gallons over a year can make a difference in the results.

When tracking fuel consumption, use actual gallons pumped at each fill-up rather than fuel burn recorded by engine software. Fuel consumption data can be off by as much as 5%. Also, there can be significant variations across various OEMs. 

We never said this would be easy.