Truck Topics

Where the rubber meets the road

Wide single tires have been with us for awhile but have not really captured the attention of the general trucking world.

Presently, wide single tire usage has been concentrated in fleet operations that are looking for, on a large scale, reduced weight, improved fuel economy and simpler maintenance.
 
Initially, these tires, known as “super singles,” required expensive retrofitting, including adjustments in gear ratios.  Around the beginning of this decade, Michelin introduced its X One wide-base single tires. 

These tires are direct replacements for dual low-profile 22.5 wheels and tires and require a 14-inch wide wheel that takes the place of a dual pair.

Michelin and Bridgestone, the two major manufacturers of single wide tires, report steadily increasing sales as more fleets and owner-operators give the new technology a second look.

A Michelin representative says that there has been a documented minimum fuel savings of 4% when converting from comparable tire types such as traditional duals to wide base singles.

Other benefits of the single wide tires include:
Lower tire and rim weight could permit increased payload, ease of maintenance and the tires are retreadable.

On the other hand (there's always an other hand, isn't there) critics say that single wides suffer from increased tread wear rate, a possible reduction in wet traction and limited replacement availability on road.

A modest number of general trucking owner-operators have taken to the new tires despite fears of tire failure, limited availability and higher prices.  They contend that the increase in fuel mileage and more comfortable ride they now enjoy more than justifies the conversion from duals.

In expedited trucking, the majority of the owner-operators who are the mainstay of this industry seem to have taken a "wait and see" approach on the subject of single wide tires.

However, there are a couple of expedited owner-operators who have taken a big step into the future and they report great results with their single wide tires.

Bob and Linda Caffee are straight truck owner-operators leased with FedEx Custom Critical.  After installing a pair of Michelin X One's on their Freightliner M2-106, Bob Caffee says the improvement was immediately noticeable: 
"Just after we had them installed at a Speedco in Troy, IL, I took the truck to St. Louis and I noticed the smoother ride right away; where there used to be a 'bump-bump' over expansion joints, now there was a single 'bump.'" 

"The ride is so much better that it's amazing!  Every little crack in the road could be felt with the steer axle but not with the drive axle.  This also helps when one of us is in the bunk with the truck in motion.  With that smoother ride, we sleep better."

So, what about the fuel savings?

Bob tells us, "I believe we're getting better fuel mileage.  There seems to be a break-in period of around 15,000 miles because you have to scrub off a little bit of rubber.  They tell you that when you first put them on, you'll lose a little on your mileage figures but it will rise after a little while.  We're seeing mpg in the high 9's and low 10's." 

Bob and Linda have around 30,000 miles on their X-One's and Bob says that Speedco was quite adamant about using the recommended pressure - 120 PSI.

"We also put the Doran air pressure monitoring system on and now we don't have to worry about under inflation," states Bob.  "That's one of the big issues for drivers with single wide tires; the main cause of blowouts is running a tire underinflated, heating it up and having it fail." 

"With the Doran system, if a tire gets 12.5% low, it will send a warning.  If it drops to 25% low, the warning will not stop."

"Right now, we're using air but we'd like to switch to nitrogen inflation.  We're going to be getting new steer tires and moving the old steers to the lift axle, so we'll get it all done at the same time."

He adds, "We may eventually put them on the lift axle but for now, we don't use the lift axle enough to justify the expense."

In response to the question of the single wides wet traction capabilities, Bob says, "I haven't taken them through snow yet but the drivers with singles I've talked to say that they actually handle better than duals."

"We went through the FedEx National Account with Michelin.  We were quoted a price of $2,800 that included trade-in of our old wheels and tires for new polished aluminum wheels and the singles."

Other concerns
Flats on the road can be a disadvantage since the driver can't “limp in” for repairs. However, general trucking fleets are reporting fewer flats with the tires because pressure is more easily maintained.

Another concern, that of availability on the road, might be a moot point.  The X One is now available at every authorized Michelin dealer in the country, in addition to many major truck stops and other outlets.

The Bridgestone Greatec single wide tire is available through authorized dealers in the 445/50R22.5 size to replace low-profile 22.5 duals.

How about those higher prices?
Prices will probably head downward as availability and user acceptance increases. Michelin and Bridgestone have offered deals that include trade-ins of duals and rims.  Increased competition from companies such as Continental and Yokohama that are presently developing single wide tires will probably reduce prices as well.

The federal government is helping the single wide evolution in its own small way:  On January 1, 2005, the federal excise taxes on wide singles decreased, and those on traditional tires went up.

From a Bridgestone sales brochure: The federal excise tax on a pair of Bridgestone M726 EL standard drive-axle duals is $50.46.  Compare that to $31.66 FET for a Bridgestone Greatec drive-axle single.

Larry and Marie Lewis are Ohio-based truck owners leased to FedEx Custom Critcal's White Glove division.

Larry says of his 2007 Freightliner Columbia SST-100:  "It has a refrigerated box and is Temperature-Validation equipped (T-Val).  The truck came from the factory with the Michelin X One single wide tires."

"We bought this truck with a tandem axle and we had to be conscious of the weight. The cargo capacity is close to 18,000 lbs. Also, with the single wide tires, there's less rolling resistance and greater stability because there's half as many sidewalls to flex vs. duals."

"These tires are easier to check pressure and the ride is so much better."

The downside?
"I haven't yet found a vendor with tire chains for the single wides that will work with this truck."

"We have a husband/wife team in the truck - Steve and Jean Brothers and they tell us that they're really impressed with the tires."

"We love the single wides," says Steve Brothers.  "We've got 33,000 miles on them and  they ride well, they handle great.  They give more of a cushiony feel than duals."

"It's like riding in a Cadillac!"

He continues, "We have a little more stability with the super wide tires.  With duals, when you're cornering with an underinflated tire, there is a squishy feel to them.  We don't have to worry about under inflation because we have the Doran monitoring system."

Steve says he isn't concerned about traction in inclement weather:  "They handle well in the rain.  I've done 65 mph in a downpour and have never seen a sign of hydroplaning.  I think they'll run great in the snow, too." 

Steve reports that mileage in this Class 8 truck is between 8.5 and 9 mpg, mileage figures that he expects will improve after an upcoming valve adjustment.

He adds, "The tires are wearing well.  With duals, you can usually see signs of wear on the inside tire by now.  These tires are wearing perfectly."

Manufacturers

Bridgestone: (800)815-9793

Michelin: (877) 966-3911