Controlling Tire Costs
Information in this piece created in collaboration with Overdrive Magazine.
Just like a truck with improperly geared rears will cost you in the long run, so too, will a truck with the wrong tires. We’re not just talking about the size of the tires either; there are many factors to take into account when spec’ing the right tire for your truck. A tire dealer can help you decide the right tire for your vehicle based on characteristics such as price, fuel economy, durability, traction, miles to removal, retreadability and tread depth and pattern. All of these different characteristics help play a role in properly spec’ing your truck and can save you money in two ways:
- Reduce tire cost per mile.
- Reduce fuel cost per mile.
In recent years, tire manufacturers have created truck tires designed to meet specific service needs. There are four main tire applications which are: long haul, regional, on/off-road, and urban. These different applications mean tire lives vary from as little as 20,000 miles for urban spec'd tires to more than 200,000 miles for long-haul tires. When you’re spec’ing a new truck, you can have any sized tire suitable for your application because the truck’s drivetrain and engine control can be spec’d to the tire size. However, when it’s time to replace the tire and you decide to change the tire size or change to a different application tire, you’ll need to make drivetrain and engine adjustments. You will also need to keep other things in mind such as the truck’s clearance if you decide to go with higher tires.
When selecting tires, more is not always better. You may be tempted to get tires with deeper tread patterns but depending on your application they may wear faster, burn more fuel, and make driving harder. Also, it’s more common now to have tires that are optimized for fuel efficiency instead of being optimized for long life. In fact, some regional fleets are switching to long-haul steers for low rolling resistance rather than tires designed for regional operations with more scrub resistance. These tires will wear faster but they save enough fuel to offset the price of replacing the tires sooner. Consider this scenario for just the tractor: The steers have a 125 rolling-resistance, the drives have 137, and the truck gets 6 miles-per-gallon. By replacing the steers and drives with lowest possible alternative (rolling-resistance of 97 and 86 respectively) improves fuel economy to 6.52 mpg. The shallower tread depth will improve fuel economy but usually translates to shorter tire life. Good news is tire manufacturers are using technology to increase the tires lifespan by using different compounding and silicate to counter the inherent tradeoff between tire life and fuel savings.
Understanding Tread by Position
Having the right tread is important when it comes to spec’ing your truck. Depending on the position of the truck and your operation, treads will be different across the truck. For example, steer tires are typically rib-type tires with medium tread depth, while drive tires tend to be more aggressive with cross grooves and deeper tread depths. Here are the different tires for the different areas of the truck:
Steer tires are characterized by having four or five straight solid ribs to support lateral forces created during normal handling and cornering as well as by wind drag. The tire’s tread pattern design and tread compound resists irregular wear in medium to long-haul service but can also be spec’d to resist cuts and chips for on/off-road service. Steer tires have tread depth to increase its longevity while offering low rolling resistance for greater fuel efficiency.
For long-haul service, drive tires will have closed shoulder ribs to prevent irregular wear and provide good handling. For regional operation, they will have open shoulders (shoulder lugs) which offers secure traction. They can be spec’d to have deep tread for long tread life, but a low rolling-resistance compound can be obtained for better fuel economy.
Trailer tires have shallower tread which delivers longer life and guards against irregular wear. They also feature strong solid shoulders for strong dragging forces and scrub. These tires have special compound to reduce rolling resistance.
Smart Spec’ing Practices
Here are some good practices to keep in mind when selecting tires for your vehicle:
Shop for the Best Value
When choosing tires, get the most for your money whether you spend a little or a lot. It may be tempting to shop just by the sticker price of the tires, but cost per mile and retreading potential are more important considerations to take then just the price alone. When you purchase the tires, make sure you keep a written and dated record of the purchase, the fuel mileage and tread depth of the tires, and compare these records between the models you used. In any case, always consider the warranty of the tires when calculating the cost.
Premium tire manufacturers design tire casings for retread use. Nowadays, tires can be retreaded up to four times after their initial tread life ends. Retreading is an attractive option for many truckers because the cost of a retread is about half or sometimes even more than the cost of a new tire. However, there are some carriers and state governments that restrict retread use on steer axles. Also, not all retreads are created equal. It’s important to get retreads from reputable dealers and avoid tires if the markings have been scrubbed off the side.
A common practice is to buy new steer tires, place the first retread on the drive, and the second on the trailer. Trailer owners have more potential for retreading because of options for repositioning tires. Casings that are rated higher with fewer repairs and lower heat history are typically placed on the drive axle since the torque on those tires leads to higher heat generation.
Use Wide Singles
You may want to use wide singles when spec’ing tires. Wide singles weigh less, saves fuel, and they often cost less than the two tires they’re meant to replace. They’re also retreadable as well. They save money in the long run, but you do have to buy new rims to be able to take advantage of them. However, you’ll be able to pay off new wheels and tires within three years of owning them. The tires will gain you 4% of fuel-efficiency attributed to the reduced rolling resistance. The only complaint you’ll hear about wide singles is its inability to limp to the next service with a flat, but that can be addressed with an automatic tire inflation system.
A low-profile tire set-up with a shorter height than width offers better fuel efficiency, handling, weight, overall truck height and tire life over more standard configurations for long-haul highway applications. The aspect ratio (measured in a percentage relative to its width at its widest point) is 100% for the most common tire - the 11R22.5. Low-pro tires’ aspect ratio is about 80% with size designations such as 295/75R22.5.
How to Preserve Truck Tires
Ensuring that your truck tires are taken care of is key to keeping your cost per mile as low as possible. Good practices and habits can go a long way to preserving the life of your tires. Here are some good tips to employ to ensure a long tire life:
Perform Routine Maintenance
The slightest irregular movements in the tie rod ends, kingpins, wheel bearings, and torque rods can spell trouble for your tire life. The pungers inside shock absorbers create fiction, and friction creates heat, so if the shock, not the outer dust barrel covering the top half of the shock, is hot to the touch after driving, it’s working. If it’s cool to the touch, that means it’s not working and should be replaced. Make sure to inspect bushings at the top and bottom of the shocks are inspected and replaced if they’re worn out. You can tell if they need to be replaced when you grab the shock absorber and can rattle them. Make sure to replace shocks in pairs at regular intervals and when there are signs of fluid leaks.
Maintain Proper Inflation
Maintaining proper inflation is the easiest way to preserve the life of a tire. Improperly inflated tires are the number one reason why tires fail or wear out prematurely as well as a cause for fuel efficiency loss. Daily pre- and post-trip inspections will give owner-operators the opportunity to check tire pressures and a chance to look for leaks, punctures, broken valve stems, or any objects embedded into the tire such as nails. Even without punctures, truck tires tend to lose about a pound or two of pressure per month from normal use. With a slow leak, they can lose about three pounds of air pressure per day. For every pound of pressure lost, the tire’s on-road temperature rises about 2 degrees and will wear out the treads a lot faster. Don’t over inflate the tires either. Over inflating tires will wear out tires more rapidly, create irregular wear, and will make the tires more susceptible to damage from running over debris and scrubbing curbs. Research shows that over or under inflating tires by 15% can reduce a tire’s life by 10% and have a fuel economy loss of up to 1.5%.
Employ Good Driving Habits
There are good driving habits and techniques you can employ to preserve your tires. Things like speeding, hard braking, curbing and tight turns cause tires to wear out faster or even develop irregular wear patterns.
Fight Irregular Wear
Check things like axles and suspension components (bushings, tie rod ends, kingpins, shocks, etc.) and replace any if they show any excessive wear. On the steer axle, replace your shocks at least as often as you change your tires. Be even more aggressive with the drive axles. Replace your shocks half way through the tire’s life and again when the tires need to be replaced.
Double Down on Alignment
You may think that you should get your tires aligned once you get new tires on, but the opposite is true. Instead, take your truck to the shop before you put the tires on so that the alignment shop can look at your worn tires to read your tire wear to learn what’s wrong with the alignment. This way, they can properly diagnose what’s wrong with your alignment. When getting your alignment, make sure that bearings are adjusted properly in all positions, and check for proper mounting which is pretty easy to do. To check proper mounting, look for a ring molded into the sidewall of tire just outside of the rim. Measure the distance from the molden rim to the edge of the tire’s rim - they should measure within 2/32-inch. If the variance is greater, the assembly needs to broken down and remounted properly.
Mounting should be followed up with a check of the radial run-down (deviation of the tire from a perfect circle) and lateral run-out (deviation of the sidewall from a perfect plane). Both measure how well the wheel assembly is mounted on to the tires hub. This can be done using a run-out gauge which cost less than $100.
It’s all too easy to oversimplify the importance of tires on a truck, but it pays off to carefully select and maintain proper tires. Not only will it save you money in the long run, properly maintained tires can end up saving your life. When it comes to unexpected blow outs or repairs caused by damaged tires, it’s important to have money saved up to take care of it immediately. However, it may be difficult to swing new or retreaded tires depending on your operation reality. If you need help paying for new tires, you can always procure funds from your unpaid invoices. Learn more about TBS’s freight factoring services to help improve cash flow off of your outstanding invoices.