Rolling resistance accounts for 30% to 33% of the total fuel cost of a modern, aerodynamic, Class 8 truck, or about $0.012 per mile with dual tires.
Before we talk about why low rolling resistance (LLR) tires are a good choice for many fleets, let’s make sure we understand what rolling resistance is. The rolling resistance of a tire is defined as the force needed to keep the tire rolling at a constant speed on a level surface and is usually expressed in the form of a rolling resistance coefficient. As tires move underneath the weight of the truck, they deform against the ground. Overcoming that deformation and keeping a tire rolling forward requires energy, and therefore fuel.
Today, fleets can choose from a wide array of tires, but LLR tires are their best option because LRR tires — whether in a dual or wide-base configuration — will save them significant amounts of fuel when compared to tires that are not designed for low rolling resistance.
Which tire configuration a fleet chooses should be based on total cost of ownership, including fuel consumption. Traditionally, tire per-mile cost was defined solely in terms of initial purchase price. But fleets that are purchasing tires without considering the fuel economy impacts of those tires are going to be miscalculating the impact of tires on their bottom line.
The reality is that the cost of the fuel that a tire consumes due to its rolling resistance is five times greater than the initial purchase price of the tire. This is important to keep in mind because it may be necessary to replace LRR tires more frequently due to the thinner tread in the tires. However, tire manufactures are continuing to work on shrinking the difference between LRR tires and non-LRR ones.
In addition to choosing the rolling resistance of their tires fleets have to decide between dual and wide-base configurations. Wide-base tires generally display lower rolling resistance when compared with a similar dual tire with the same tread pattern and rubber compound. However, not all wide-base tires will outperform all LRR dual tires, and fleets need to make configuration decision based on their operational needs.
In the update to our Confidence Report on low rolling resistance tires in dual and wide-base configurations, we provide a decision guide to assist fleets in making selecting tires and we also include a payback calculator that allow fleets to input various operational features such as the axle configuration of their tractor and trailer and associated miles driven as well as tire-specific data for the steer, drive, and trailer tires that are under consideration. The calculator then gives the fleet the total cost of ownership for the various tires based on their own data.
Given the impact rolling resistance has on a fleet’s fuel consumption, it makes sense to spend some time figuring out just which tires will be the best value over their useful life based on a fleet’s own operating parameters and needs.
