You’ve heard the saying an Oldie but a Goodie? I think, the 6x2 axle idea is an Oldie Made a Goodie with Recent Technology. Back in the 1970s when fuel prices went through the roof, the trucking industry worked overtime to come up with ways to improve fuel economy. Some of those solutions caught on and are still with us while some never really took off although they showed promise.
One of those solutions is 6x2 axles. And if you’re not currently spec’ing them, now is the time to give them a second look. The 6x2 configuration has enjoyed widespread use in Europe, but has not really caught on here. It puzzles me why North American fleets are slower to adopt this technology especially since the early adopter fleets that have switched to 6x2s are enjoying improved fuel economy.
Earlier this year, NACFE along with the Carbon War Room, published our Confidence Report on 6x2 axles (you can access it at www.truckingefficiency.org). After interviewing fleets using 6x2 axles, reviewing data from OEM testing of 6x2 axles and conducting our own fuel efficiency tests on trucks equipped with 6x2 axles we have confidence that this is a technology that offers increased fuel efficiency and a decent payback. Overall you can expect a 2.5% improvement in fuel economy using 6x2 axles and payback should be around 20 months.
But these are not the only benefits of switching to 6x2 axles. Weight reductions of 400 to 450 lbs. were realized when fleets switched to 6x2 axles since tag axles weigh less than a driven axle. Since the 6x2 configuration reduces the total number of driveline components, maintenance cost savings should be in the $100 range even considering the addition of electronics needed for the systems.
One often overlooked benefit of adopting 6x2 axles is the improved stability and control they provide when the truck is operating in slippery or poor road conditions. Remember the tag axle on a 6x2 can’t spin up because it is not powered, so there will always be some degree of lateral force available to keep the vehicle stable.
There are two primary challenges with adopting 6x2s; loss of traction and tire wear. By and large the traction issue has been addressed with the addition of automated electronic load shifting systems that are integrated into the truck’s electronic systems and work in conjunction with the electronic traction control systems already on the truck. For a great discussion of this visit www.6x2facts.com. And secondly, there is likely increased tire wear. As all of the torque is provided through one versus two axles, tire wear must be managed. For instance, trailer tires can be added to the tag axle and spec’ing considerations should be a focus on the drive tires.
Sometimes something old can be something good, especially when new technology helps. With 6x2 axles this has proven to be true.