Editor's note: This is part two of an article exploring today's commercial vehicle tire trends, issues, and innovations. Read part one.
With more digital tools to track efficiency gains, fleets are now able to get a better sense of how much they can save. That data should strengthen the case for the proliferation of low rolling resistance (LRR) tires, which facilitate better fuel economy. Overcoming rolling resistance expends up to 33% of a truck’s overall fuel consumption. A reported 80% of new trucks and trailers are spec’ing LRR tires, according to the North American Council for Freight Efficiency (NACFE).
The U.S. Environmental Protection Agency tracks what is classified as an LRR tire via the agency’s SmartWay program. The list has expanded from eight models in 2010 to 300 in 2020.“Even though the upfront costs of low rolling resistance tires may be higher, 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,” explained Mike Roeth, executive director for the North American Council for Freight Efficiency.
Besides the higher cost, the trade-off with LRR tires had been less durability, with earlier versions wearing faster, though manufacturers are always making this a focus of continuous improvement. “Very low rolling resistance is achieved by a blend of tread compound, tread pattern, and the construction of the tire—the sidewall in particular—as well as by keeping the overall weight to a minimum,” Continental’s Fanning pointed out. “All of these measures need to be carefully coordinated in order to ensure that these tires retain their very safe handling properties.”
Tire manufacturers have been addressing this with a combination of material and design innovations.
Yokohama’s 715R open shoulder regional drive tire, launched in June, leverages a proprietary cut and chip resistant compound that also reduces rolling resistance. It’s still rated for severe snow service with tread that minimizes foreign objects from getting stuck and deep 26/32-in. tread pattern to reduce heel/toe wear. “Yokohama is constantly evolving developments as the OEMs continue advancing their products,” according to Tom Clauer, Yokohama Tire senior manager of commercial product planning. “Because regulations and demand for low rolling resistance products by fleets will increase, Yokohama will continue to work on new compounding and designs to meet these issues now and in the future.”
Michelin has developed a design called Regenion Tread Sculpture, which uses alternating channel grooves that displace water more efficiently as the tire wears. This ends up allowing for better grip and braking on wet roads.
Bridgestone’s latest offering, the R13 Ecopia all-position radial tire, was developed to improve rolling resistance and durability. This was achieved through a combination of less bead filler in the sidewalls to reduce weight, along with high-tech polymers and tread compounds. The company claimed this version has a 6% improvement in rolling resistance over its predecessor, the R284 Ecopia, while improving wear performance by 15%.
“There’s a new edge siping that helps with the shoulder durability and basically some of the abuse that those tires take,” said Matt Schnedler, Bridgestone’s senior product manager.
Continental is also adding products to serve the needs of growing fleet duty cycles. Tom Fanning, head of U.S. market, truck tires, pointed to the Conti HDL 3 LTL drive tire designed specifically for less-than-truckload (LTL) applications. It’s available in 295/75R22.5, with additional sizes coming in the latter half of 2021.
For tire makers to address current needs requires a good deal of foresight. “We need to be thinking a few years ahead because the tires we’re launching today, we started developing three or four years ago,” Schnedler said.
In the next several years, the performance of LRR tires will be even more paramount, as electric vehicles enter the commercial space in larger numbers. Better rolling resistance equals longer ranges, which improves the EV’s value proposition. But the power generated by the electric motors comes with a cost.
“In electric vehicles, you get the maximum torque when accelerating right from the very start; vehicles with combustion engines take longer to get up to speed,” Fanning told FleetOwner. “Tires on electric vehicles can therefore be subject to greater levels of stress during acceleration, which, in turn, affects their endurance and wear values.”
Fanning also pointed out that the use of regenerative braking “puts added strain on the drive axle tires.” The other issue is that commercial electric vehicle batteries will add as much as 2,000 lb. to the gross vehicle weight.
“We’re already getting pretty close on the steer axle to the weight limitations there, certainly for a load range G tire, and now we’re pushing the zone load range H tire so that weight distribution is going to be critical,” offered Michelin field engineer Mike Steiner during a NACFE webinar.
He also noted Michelin expects accelerated wear on EV tires.
“The main takeaway here is that we need to heighten our awareness. Tire selection is a pretty big deal when it comes to making that transition to an electric vehicle,” Steiner said.
This means more training regarding new tires, retreads, and maintenance such as regular tire rotations, he said. Maintenance bays may also need to consider managing different air pressure parameters for diesel and electric trucks. Steiner’s advice is to start getting employee buy-in right away.
“It’s even more important to get them to understand why your company’s doing it and how they can be a contributor and take some ownership. You’ll be a whole lot more successful if you’re able to do that at the very beginning,” he concluded.
Yokohama’s Clauer noted that each type of vehicle, be it a van or tractor-trailer, will have individual requirements: “Ultimately it will come down to a balancing act between some obvious weight and torque considerations for EVs and what is asked of the tire, from high scrub applications to longer wearing, lower rolling resistant coefficient applications.”
Sustainability and retreading
EVs are only one way for the transportation industry to achieve sustainability goals, and the jury is still out if they will provide net emissions reductions when factoring in rare earth mining and how the electricity is generated. A more surefire impact can be had through retreading tires.
The problem is that many smaller fleets often opt for lower cost Asian imports that cannot be retreaded. While at least 87% of fleets with 100 or more trucks retread, only two-thirds of commercial fleets with 25 to 99 trucks, 55% of fleets with five to 24 trucks, and 34% of fleets fewer than five trucks did so, according to a 2018 joint study sponsored by Bridgestone’s Bandag business. The study is titled “Retread Tires in the United States & Canada: An Analysis of the Economic & Environmental Benefits for Fleet Operators and the United States Government.”
The study pointed out that in 2016, a premium new tire ranged from $375 to $500 and a retread $100 to $200, while an ultra-low-cost tire was $150 to $275. The thought here is that the exporting nations subsidize their tires to make them more competitive, though the environment ends up picking up the bill.
According to a 2016 Ernst & Young study based in Europe, a “well manufactured tire” capable of being retreaded has the following environmental advantages over the less expensive one-and-dones: 24% carbon dioxide reduction, 70% less natural resource extraction, 19% less water consumption, 21% less air pollution, and 29% reduced land use.
The Bandag study also found the U.S. and Canada tire retread industry saves 217.5 million gallons of oil annually while keeping 1.4 billion lb. of tire scrap out of landfills. Bandag prevents 7 million tires from entering the waste stream per year, while the retreading sector overall reuses 15 million each year, Kyle Chen, channel manager for fleet and OE TBR at Bridgestone Americas, said.
“The challenge has always been convincing the decision maker at the small fleet that retreading was the way to go,” noted Kevin Rohlwing, SVP if training for the Tire Industry Association. “They feel more confident in a brand-new tire, even if it is from a country they’ve never heard of, with a name they can’t pronounce, because it’s saving them a lot of money.
A low-cost import can be nearly half the cost of a higher quality retreadable tire manufactured in the U.S. They are also subsidized by foreign governments. Risk is another reason smaller trucking fleets don’t want to spend too much on new tires. That new $400 tire could be destroyed by a wayward piece of rebar or pothole, so spending just $200 for the import option mitigates that potential loss.
A small fleet might also not compare how damage loss stacks up to cost-per-mile savings from a more fuel-efficient retread-able tire. Digital tracking can be cost-prohibitive for some fleet operations, and those carriers then can’t validate the cost savings from a retread. As Rohlwing pointed out, those fleets are “not tracking mileage; they’re not tracking cost per mile. They’re simply looking at that as an expense.”
Because of this type of thinking, ultra-low cost import share in the replacement market increased from 4% in 1998 to 17% in 2016, while retread dropped from 54% to 44%. Over that time, 41% of U.S. retread plants shut down—about 455 total.
Retreads are put through rigorous testing to ensure quality, and not all casings are accepted for the process. Underinflation appears to be a more likely cause for those road gators, according to research. In a dual tire configuration, identical air pressure is crucial. A 2008 National Highway Traffic Safety Administration Commercial Medium Tire Debris Study found that with “uneven dual-tire operation, the tire that is dragged generates excessive heat and may eventually fail, and the remaining tire is subjected to carrying more weight than it was designed for and can also fail.” The study also cited five reports indicating similar findings.
“The perception of retreads is a constant barrier that we try to overcome,” Bridgestone’s Chen acknowledged. “Drivers see pieces of rubber on the side of the road, and they automatically think it’s a retread, which isn’t true.”
In the end, fleets will have to experiment to discover what combination of these trends will work for them, and help them overcome barriers. By doing this, they will lower their cost per mile, ensuring their trucks will be rolling for years to come.
