Low Rolling Resistance Duals
Low rolling resistance (LRR) dual tires will save significant amounts of fuel when compared to tires that are not designed for low rolling resistance.
Cost per mile of tires has traditionally been defined in terms of initial purchase and tread life. However, the cost of fuel the tire consumes because of rolling resistance is five times greater than the initial purchase price of the tire. Rolling resistance makes up 30-33% of the total fuel cost of a Class 8 truck or about $0.13 per mile. The typical purchase price of the tire is about $0.038 per mile.
But given the range in rolling resistance among dual tires on the market today, tires could be claiming anywhere from $0.14/mile to $0.28/mile in fuel costs. Put simply, fleets that are purchasing tires without considering the fuel expenditure impacts of those tires are going to be miscalculating the impact of their tires on their bottom line.
Some of the costs to operate low rolling resistance tires may be higher than those of non-LRR tires, but those costs are recovered over the life of the truck. The cost of the fuel a tire consumes due to its rolling resistance outweighs the initial purchase cost of the tire by a factor of 3.4.
Reduced Fuel Consumption
- Since tire rolling resistance accounts for about one-quarter to one-third of truck fuel consumption decreasing by rolling resistance 10% the result is about a 3% decrease in fuel consumption.
- There is a large range of rolling resistance in commercially available tires today, so the fuel efficiency will vary widely.
- Choosing tires from SmartWay’s Verified list of low rolling resistance tires contributes to a fleet’s sustainability goals.
- California regulations call for low rolling resistance tires on certain trucks and tractors.
Initial Purchase Price
LRR tires are priced similarly to, and in some cases less than, non-LRR tires.
Irregular/Premature Tread Wear
- Shallower tread can lead to fewer miles overall, but more recent tire advances are extending tire life.
- Some fleets are willing to give up some mileage if the cost of the lost miles can be made up in fuel savings.
Life-cycle Cost vs. Initial Purchase Price
- Initial purchase price of low rolling resistance tires can be a few percent higher than for non-LRR tires.
- It can be difficult to determine actual fuel savings.
Common Fleet Strategies
Most fleets use the SmartWay verified list as a guide for finding LRR tires. Distributors or tire company representatives can help point fleets to tires that may be best suited for their application. Large fleets may run their own tire tests to determine which LRR tires make the most sense for them.
Premature tire wear is often the symptom of some other problem on the vehicle whether the tires are non-LRR or LRR. Simply replacing a prematurely worn tire with a new tire without addressing the underlying problem will result in premature wear of the new tire as well.
In order not to lose the benefit of LRR tires, fleets should:
- Conduct regular alignment checks
- Ensure wheels are properly balanced
- Ensure tires are mounted correctly
- Keep tires properly inflated
- Make sure tire diameters are matched for dual tires
NACFE developed several tools including a Confidence Matrix, decision guide and payback calculator to assist fleets in evaluating low rolling resistance tires. The Confidence Matrix shows how confident NACFE is in the adoption case for low rolling resistance duals. The Decision Guide summarizes the study findings to assist fleets in making decisions about low rolling resistance and wide-base tires. A Total Cost of Ownership tool calculates life-cycle costs of different tires fleets are considering.
- Low rolling resistance tires, whether in a dual or a wide-base configuration, save significant fuel.
- The purchase price of LRR tires may be higher than non-LRR tires, but these costs can be overcome through fuel savings when considering life cycle cost.
- Adoption of LRR tires in the over-the-road trucking is high and will continue to increase
- The perception of traction issues or driver acceptance problems is worse than the reality.
- The MPG gap between the lowest LRR dual tires and the best wide-base tires continues to narrow.
- Fleets should understand the total life cycle cost for tires in their specific operation, including the up-front purchase price, weight, wear, retreadability, etc.
- Fleets should use the lowest rolling resistance tires for their specific needs from a trusted manufacturer. Tires on the SmartWay Verified List of Low Rolling Resistance New and Retread Tire Technologies meet only a specific rolling resistance threshold and can encompass a wide range of quality, fuel efficiency and service life.
- Tire manufacturers should continue to develop even lower LRR tires while continuing to lessen the tradeoffs in traction and tread life.
- Tire manufacturers should work to agree on a testing protocol, with the goal of making CRR data widely available to tire purchasers.
- Tire manufacturers should publicly share the rolling resistance coefficient (along with wearability and wet traction) for all their tires once industry-wide collaboration and agreement on a standard testing protocol is achieved.
- Tractor and trailer makers and their dealers, industry associations, EPA SmartWay, TMC, NACFE and others can better assist fleets in these decisions by making data more accessible to tire purchasers.
- EPA SmartWay should develop tiers of rolling resistance tire categories to encourage early adopters to utilize the best tires for their needs.