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ORNL: Single Wide-Base Truck Tires Improve Fuel Economy


Replacing the standard two thinner tires per wheel with a single wide-base tire improves the fuel efficiency of heavy-duty tractor-trailer trucks and allows them to be made to run with more stability, according to studies by Oak Ridge National Laboratory (ORNL).

Interstate tests by ORNL’s National Transportation Research Center show gas mileage increased nearly 3% with use of wider single tires on tractor-trailers. Bill Knee, who headed the study, said the change also allows widening of the trailer frame by six inches, providing a much more stable configuration.

We noticed that there was about a 2.9% fuel saving in using the new generation single wide tires over the standard dual tires. These trucks do 125,000 miles per year on the average. They currently get five miles per gallon. You can see there is a considerable amount of savings dollar-wise that can be realized through tires like this.

—Bill Knee

With those figures, a 3% improvement in fuel economy would reduce fuel consumption by about 728 gallons per year per truck.

The wide base tires improve fuel efficiency by decreasing weight and rolling resistance. Knee said tire formulation and the design of the tire are likely contributors to the fuel savings.

The fuel economy tests were conducted along a route from Western Michigan to Portland, Ore., that involved many types of terrain, varying weather conditions and different levels of congestion.

A 2005 study by the EPA on single wide truck tires and aerodynamic devices singly and in combination on Class 8 vehicles using a test track found improvements in fuel economy ranging from 3 to 18%—and, surprisingly, NOx reductions ranging from 9 to 45%.

ORNL will conduct additional testing of five instrumented trucks over a 12-month period beginning this fall. Lessons learned from these types of studies are preliminary to further efforts to develop a heavy truck of the future that will be more energy-efficient and stable than conventional trucks. The research is funded by DOE’s Office of FreedomCar and Vehicle Technologies.



Rafael Seidl

3% is a big deal in an industry with paper-thin margins. I would expect this technology to be adopted fairly quickly (relative to other innovations in this highly conservative sector).


I wonder if there is a safety issue with the dual tires.


Maybe this will be 3% of the 100% improvement that Amory Lovins is trying to achieve for Wal-Mart. IIRC, Wal-Mart fleets already achieve 7 mpg; target is 14 mpg.

Mark A

I have seen an 18 wheeler on my commute pass me with a single wide wheel, as opposed to two smaller duals. Just think of the large chunks of rubber that will be left on the highway if one of these blows, instead of one of the smaller duals. I would also wonder about safety if one of these blows, as opposed to only one of the duals blowing, as far as maintaining vehicle control.

This does go counter to standard knowledge that a high pressure narrow tire is more fuel efficient that a fatter tire, in a car applications. Maintaining tire pressures will become more mandatory to maintain tire life. Hopefully tire pressure monitors, and onboard air compressors will be necessary to maintain these tires.

Scott Van De Weghe

When you get a flat on super singles, you destroy the wheel & your savings go up in smoke.


This concept has been around for more than a dozen years (maybe even longer). If it's gonna be adopted fairly quickly I think it would have become standard operating practice by now, What gives??

John Ard

My father is a penny-pinching indepenent trucker, so I decided to post his thoughts on this subject:

Singles can't carry the same weight that a set of duals can. This is alright for hauling chips or other loads with a standardized or low weight, but not good for owner-operators like my father who must pull whatever fits on the trailer to pay the bills. Also, when a tire blows with duals it is possible for the truck to limp onward to a shop or off of the road. Singles don't allow for this. Finally, singles require different rims which brings the cost to a level that a 3% increase in fuel economy can't quickly correct.

Bike Commuter Dude

1)In the event of a blowout (with any kind of tire), the law usually states that the driver must remove his "alligator" or blown casing from the roadway. Same goes for roadkill. So, the added size/weight of a super single casing should be irrelevant if the driver actually does his/her job.
2)My father ran over twenty five miles on a dead super single, with no resultant rim damage.
3)Any trucker in the United States is limited to 80,000lbs GVW, so nobody pulls any more weight (with the exception of Overweight/Oversize/Piggyback loads) than that reguardless to what "fits the trailer". In addition, there are weight restrictions on each individual axle, so that they are uniformly loaded.
4)The difference in cost between 1 super single rim, and 2 standard dually rims, is certainly a fraction of the approx. $2100/yr. fuel cost savings.

John Ard

Last I heard singles couldn't support a 80,000lb GVW. It's been a while though so maybe I'm running on old info. Could someone provide a link to enlighten me?


Here is a useful link:

It seems that link (and wikipedia) both agree that super singles let you add MORE payload then normal due to the lighter arrangement of single tires & single rims.

What else will ORNL look at for the improvement of the efficiency of trucks?

John W.

Hi Mark, this doesn't go contrary to standard knowledge at all: one fat tire is less efficient overall than one hard skinny tire, yes, but not more efficient than *two* skinny hard tires it replaces. That's key here.

Generally there are plenty of tires on a truck with trailer to share the load; I don't see any significant risk here, esp if the tire manufacturers have produced tires at at least the same quality level.

Everybody, don't forget another obvious advantage of these super slicky singles: they add to the "mag" look of your tractor! This might promote a whole new tuner industry! Just kidding.

John W.

oh one more thing, if these single rims are incorporated into the oem equipment list as the truck leaves the factory, the cost difference from the current setup will be negligent. If you had to retrofit an already set up truck, that would be different of course...


Mmmm, why 18 wheelers using a dual tires in the first place? If for safety reason, we really should not trade our safety with a marginal cost saving.

In terms of rolling resistance, I believe there will be more interest on reducing rolling resistance of current design.

In terms of resource, dual tires or wide-based tires, which one using up more rubber? And how is the durability? Tire grade rubber, if i not mistaken, must import from foreign tropical country, and is getting more expensive day by day.


I saw my first semi-tractor using super singles last weekend.  To my surprise, it was not a Wal-Mart truck.

allen zheng

The thing is it is easier to replace than a compromised inner wheel in dual arrangement. The military is already going singles where they used to go duals. 2.5, 5, 7 ton tactical trucks all have single tires where past designs had duals. The issue of alligators may be addressed by using better belt/tire materials/designs so that a tire failure will not jeopardise drivers around and leave significant debris.
___There are some indistructable tire, for civilian considerations, designs that comprise of matrixies of betal/composits, and do not have to be inflated. However, they are loud when running at faster than 30mph, and some are too hard for use on bumpy roads (damage to road/suspension and ride too bumpy).

tom deplume

The law requires only new tires on the front but allows retreads on the other 16. In my years of bus driving I only experienced tread separation once. It is a progressive event which could be detected with a simple pressure switch mounted above the tire that could sound an alarm alerting the driver before total separation occurred. It is such a simple device so I believe its lack is due only to a lack of a government requirement.


I drive for a company with a fleet of approx 100 trucks, Our VP has 7 power units on order with " super singles " when I ask him WHY ? he said all the things I see posted good and bad HOWEVER he like yous couldn't answer the on question that I feel is MOST important HOW do they handle in adverse conditions EG, rain ,snow, ice, ect. I already see a large number of drivers scared to death over a little snow what now MORE TRUCK STOPS!

Patty and Bob Seidl

We drive a new truck with super singles. The ride, fuel mileage and less weight make them superior. And then we got to use them in mountain snow, ice and blizzardy conditions. All we can say is GIVE US OUR DUAL DRIVES BACK!!!! They have horrible grip in Wymoing snow and ice. We were side ways more often than straight sometimes. Best dry road tires ever, but in winter conditions you have zero control. The chains weigh about 80 to 90 lbs and are extremely difficult to handle. 2 person job. We have been driving for over 11 years and 1.5 million accident free miles.


where can i get a set??? get with todays technology..everytime something new comes out people talk junk about it with out tring it ... I haul tankers for my self.. I'll give them a run....

Crystal Jones

My company has tried single wide tires and found that it did save a small, noticable difference in fuel saving vs. dual tires, but the cost takes up the saved fuel cost. These single wide tires make the truck more stable but at the same time, in different circumstances, makes it more dangerous for our drivers and any other person around the truck. Driving, as you know, is a dangerous job in itself and could very possibly be a fear of anyones, when an added danger is in place is when people's fears overcome them and also when accidents happen.

Barry Andersen

an even greater fuel savings was achived from our cutomers using super singles. see how at


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I've run super singles on the front of snowplow trucks because conventional tire/wheel combos were not rated to haul enough weight. I've not tried them on the rear.

One factor with 'alligators' and shredded tires in general is that it's often the inside dual that's the culprit. I suspect that's because it's difficult to check the air pressure, and a whack with a tire hammer tells you if there is SOME air in it but not how much, especially in cold weather.

If the inside dual is flat the outside one is taking WAY more load than it should, especially cornering, so a super single that's properly inflated should be less likely to disintegration than improperly inflated duals, yes?


Yes, but don't they increase rubber waste?

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