Some tires considered the cream of the crop 20 years ago would not even make today’s EPA SmartWay list. That’s how much tire technology has evolved.
“In the 1990s, tread designs were relatively static,” says Mike Manges, communications manager for commercial and off-highway tires at Goodyear. “Boiled down, there were basically two designs, rib or block and variations thereof. Today, tread designs are much more sophisticated and are tailor-made to fit specific applications and wheel positions.”
Tread geometry has changed significantly, along with the size and design of the tire's shoulder and tread elements. Blading, for example, has become more sophisticated, helping primarily to improve traction, not only when the tire is new, but through the life of the tire, Manges notes.
New manufacturing processes have made advanced siping possible. These provide additional traction in a tread designed for low rolling resistance. And today’s casings are generally more retreadable than previous designs, adding real savings to a tire’s overall lifecycle cost.
Perhaps the biggest improvement to come along is one you can’t even see: rubber compounding. Advances in rubber chemistry and the ability to blend different compounds for specific areas of the tire have allowed tire makers to optimize tire designs.
“‘Dual Energy’ compounds contain a top layer to provide exceptional removal mileage and a bottom layer which allows the tread to run cool, minimizing internal casing temperatures for low rolling resistance and extended casing life,” says Paul Crehan, director of product marketing at Michelin Americas Truck Tires. “Unique Energy compounds incorporated into [Michelin’s] fuel-efficient tire sidewall designs have helped reduce rolling resistance and delivered significant reduction in irregular wear for up to 15% improvement in removal mileage.”
Today’s fuel-efficient treads
The hot commodity in truck tires today, especially in the longhaul sector, is fuel efficiency. That’s often referred to by a measure of the tire’s rolling resistance. Tire makers and SmartWay use a rolling resistance index to rank tires for fuel savings potential, but those numbers are never shared with tire consumers. So what does a fleet have to go on during the spec’ing process other than the tire maker’s word and any internal testing they might do?
For this month’s feature we asked for plain-English remarks from five tire manufacturers describing their latest tire and tread designs. Here they are, in alphabetical order.
Bridgestone Bandag TR4.1 retread
New tires aren’t the only place that has seen huge advances in tread technology. Retreads have, as well. According to the company, the Bandag TR4.1 retread provides affordable and dependable tread wear and overall life performance for small to medium truckload, less-than-truckload and pick-up and delivery fleets.
The TR4.1 retread features include:
- Smooth and continuous shoulder to promote uniform wear;
- Bandag’s proven tread compound contributes to long life and even wear;
- Circumferential grooves help to evacuate water which improves traction in wet conditions; and
- Diagonal tread block edges to promote traction on wet and dry surfaces.
The TR 4.1 is available in sizes 210mm through 240mm to fit most casings commonly used in the recommended applications.
The retread rounds out the Bandag portfolio for trailer applications, offering a balance of price and performance.
Continental Hybrid HS3
Prosser Carnegie, product development manager of Continental Truck Tires for NAFTA, says the HS3 is an all-position tire aimed at the “hybrid market” for fleets with mixed long-haul and regional operations.
“The Conti Hybrid HS3 was designed with a five-rib pattern to equalize pressure across the footprint while improving mileage given its operating conditions,” he says. “Within the grooves lay specialized stone bumpers to prevent the trapping of rocks and stones during regional type of applications.”
In order to address the conflict between fuel efficiency and overall removal mileage, Conti relies on its innovative “Fuel Saving Edge.”
As with all of Continental’s 3rd Generation products, the Conti Hybrid HS3 was engineered for the 3G casing. The 3G casing increases fuel efficiency by reducing overall deflection of the casing to minimize heat build-up and rolling resistance. Also, the casing is physically wider so tread patterns can to be tuned to their maximum width potential for optimized mileage and traction.
The 3G casing is a standardized platform found in all of Conti’s 3rd generation lines and wheel positions. This makes casing management easier because they are all consolidated to a single retread width.
Goodyear Fuel Max RSA
Norberto Flores, marketing manager, Goodyear, says the company’s new SmartWay-compliant Fuel Max RSA delivers excellent fuel economy for regional/long haul driving with enhanced toughness for urban environments.
“The Fuel Max RSA’s tread is non-evolving, which helps maintain traction throughout the life of the tire,” says Flores. “We are confident that the new Fuel Max RSA will be enthusiastically embraced by fleets that are looking for an excellent all-around regional tire to help enhance their operational efficiency and ultimately lower their cost-per-mile.”
Elements of the Goodyear Fuel Max RSA’s tread design include:
- Robust and wide shoulder rib design to help improve curb impact resistance;
- Goodyear’s exclusive IntelliMax Rib Technology, which provides a stiffer tread to help deliver lower rolling resistance, higher mileage and even wear in combined highway and urban driving applications.
- Biting sipes to help deliver good snow traction by increasing the number of edges that are in contact with the road. By varying sipe orientation, traction can be improved during acceleration and braking, or for grip when cornering.
- Optimized blade geometry and sequence of the sipes to enhance wet grip; and
- A 20/32-inch tread depth to help boost fuel efficiency.
Michelin X Multi Energy Z
Paul Crehan, director of product marketing for Michelin Americas Truck Tires, describes the Michelin X Multi Energy Z as an all-position tire suitable for steer, drive and trailer axles in regional and emerging super-regional applications.
“It’s aimed at package delivery, dry van LTL, food and beverage delivery and P&D operations,” he says. “It is engineered for SmartWay-verified fuel efficiency, long tread life and durability.”
Fuel efficiency and mileage are delivered using Michelin’s Dual Compound Tread technology, featuring a top wear layer of tread over a fuel and durability bottom layer. The top layer is designed to be resistant to scrubbing, tearing, etc., while the bottom layer, low in rolling resistance, runs cooler. The Michelin X Multi Energy Z achieves durability and fuel efficiency because of the dual compound tread. The two main elements are the use of any energy casing and the two-layer tread compounding. Casing life is extended with curb guards to protect the sidewalls from impacts and abrasions, while groove bottom protectors help prevent stone-drilling and a full width elastic protector ply offers casing protection. Crehan claims the X Multi Energy Z has up to a 15% reduction in rolling resistance compared to previous Michelin products. Handling is improved with inter-locking Matrix sipes.
Rick Phillips, vice president of sales, Yokohama Tire Corp., calls the 709ZL a unique commercial tire product.
“At first glance you might not even associate the 709ZL with a drive tire because of its tame appearance,” he notes. “But when you understand the engineering that went into the tread design and actually look below the surface, you know it’s anything but tame.”
Some of the key features in the tread design include:
- A shallow 26/32 tread lowers rolling resistance for better fuel efficiency.
- Four strategically designed circumferential grooves allow for water evacuation and added traction in wet weather. These same grooves then transform into a varying direction, serpentine groove at the base of the tread. This adds stability and better handling characteristics while reducing tread squirm, which also lowers rolling resistance.
- The unique “Z”-shaped tread blocks create thousands of biting edges to improve traction in snow and all types of inclement weather. The unique shape of the blocks also support each other and provide extra rigidity which promotes smooth, even wear by reducing the likelihood of heel and toe or cupping wear.
- The tread compound gives the rubber qualities that allow all these elements to be combined in a way that produce a well-balanced and very cost-effective drive tire, according to Yokohama.