However, the company is striving hard to call its new X-1 linehaul tractor and trailer single tire by another name, especially to avoid the “super-single” and “wide-base” monikers applied to such products in the past.
“Wide-base and super-single refer to severe-service tires common to dump trucks and cement mixers,” said Michael Hurley, market analyst for Michelin’s longhaul tire products speaking at TMC’s annual meeting and expo. “Our X-1 single tire for tractor rear axles and trailer axles is a completely different animal.”
Hurley said wide-base severe service tires, for example, have much thicker sidewalls and treads to resist cuts from stone chips and gravel. They are also designed to run at low speeds with high tire pressure, 130 lbs psi.
The X-1, however, is designed to run at high speeds with lower tire pressure, 100 lbs psi. Severe service tires are also set inboard of the chassis frame and are 2.3 inches higher than linehaul tires. Combined with the higher tire pressure, that makes the ride stiffer and less stable – ideal for manuevering around a job site at low speed, but not for highway driving.
Hurley thinks that once fleets get over misconceptions about the linehaul single, then its benefits become plainer. Most tire failures on tractor-trailers today occur on the inner dual tire, said Hurley – the one most drivers and technicians find hard to check. Also, the axle support for duals can ‘mask’ underinflation in some cases, setting up a tire failure scenario, he said.
That’s why Hurley said Michelin was attracted to the concept of a linehaul single. Instead of checking eight tractor rear-axle tires, for example, now only four need to be checked. Visual inspections and air pressure checks are thus easier. And by using four tires instead of eight on the tractor rear and trailer axles, Michelin said its test fleets saw fuel efficiency improved by 5%.
Weight savings are also possible. By using all-aluminum wheels, linehaul singles can cut up to 880 lbs from a truck running duals on its rear and trailer axles.
Right now, one X-1 linehaul single costs the same as a set of duals, a sticker shock that still has some fleets staying on the sidelines. But Hurley thinks the advantages will become more apparent over time.
“Fleets are easing into this,” he said. “The most economical way to get these tires is on new equipment, so they making a measured response so far.”
