Truck component maker Meritor expects to offer a new tandem axle dubbed the “SMARTandem” in 2013 that combines the benefits of 6x4 and 6x2 tandem designs into a 6x2 package that saves weight and helps boost overall tractor fuel economy without skimping on performance.

“We’re looking at a variety of ways to boost drive axle efficiency and save fuel to help OEMs meet greenhouse gas (GHG) regulations,” Charles Allen, Meritor’s general manager for rear axle drives, explained during a press event at the company’s axle manufacturing facility in Fletcher, North Carolina.

[To view photos from that event, click here.]

Allen noted that Meritor is in the midst of wrapping up two years worth of field tests with 15 customer trucks equipped with its new SMARTandem 6x2 axle configuration that he believes successfully combines lighter weight and fuel savings of a traditional 6x2 setup with the performance characteristics of a traditional 6x4 design.

“We’ve drawn features from all our tandem axle models, especially the FUELite and 14X products, for the SMARTandem design,” Allen said. “The SMARTandem offers about 400 pounds of weight savings and a 2% improvement in fuel economy, but it also rated to handle a GCVW [gross combination vehicle weight] of 110,000 lbs. and 2,050 ft.-lbs. of output torque. It also features automated traction control, load shifting, and an automatic differential lock to give it traction equivalent to a 6x4 model.”

Matt Stevenson, Meritor’s GM of North American field operations and marketing, told Fleet Owner that the SMARTandem also features design influences from the company’s 17X rear tandem axle produced for the European truck market and, when combined with wide-base tires on all wheel positions, can save nearly another 400 lbs. in weight and boost tractor fuel economy another 1% for a 3% overall improvement.

Stevenson noted, however, that the 6x2 tandem axle configuration remains a relative rarity in the North American truck market, with a survey of 500 customers conducted by Meritor indicating that only 18.6% of those fleets operating more than 100 trucks equip them with 6x2 tandems, with only 16.3% of those operating 100 or fewer trucks selecting the 6x2 model.

“The objections to the 6x2 are typically over less traction, less resale value, and increased tire wear,” he said. Yet the traction boosting technology added to the SMARTandem along with adding as standard Meritor’s electronically-controlled air suspension (ECAS) system to alleviate excessive tire wear should eliminate those concerns, Stevenson believes.

“The resale ‘penalty’ for a 6x2 versus a 6x4 tandem we’ve seen in our research is about $5,000; but we think the fuel and weight savings offered by the SMARTandem could offset that and more over a four year ownership period,” Stevenson said – noting that the SMARTandem is currently “price neutral” in comparison with Meritor’s 14X 6x4 tandem product.

“This should be a ‘no sticker shock’ situation,” he stressed.

“In our field tests, which we’ve been conducting since November of last year, the trucks equipped with the SMARTandem have been attaining 7.2 to 7.5 miles per gallon (mpg) – a rough 2% boost to their baseline fuel economy,” Allen added. “In our calculations, with diesel costing $3.80, the truck averaging 7 mpg over 100,000 annual miles, that 2% adds up to $1,064 in fuel cost savings per year.”

Stevenson emphasized that the SMARTandem won’t be an ideal fit for every fleet, as its best suited for those operating on mostly flat stretches of roadway at highway speeds – not mountain driving, for example, which is where the 6x4 configuration is ideal.

“The point is though that we’re simply running out of ‘low handing fruit’ in terms of how to achieve fuel efficiency gains – and the impending implementation of GHG rules is speeding up the demand for such gains,” he said. “That’s why we think that while the 6x2 configuration only makes up 3% of the tandem axle market, it will comprise 18% of the market within 5 years.”