Going downhill with a big trailer on the hitch can be nerve-wracking for drivers due to the weak … [+]
If there’s an Achilles Heel to towing a heavy trailer with a pickup truck, it’s the braking power. Truck makers tout torque and power for getting heavy loads up a hill, but when drivers reach the summit and the grade begins to descend, it can truly be a white knuckle experience if there’s a heavy load on the hitch.
Sure, most big trailers come with “trailer brakes” that are activated when the driver steps on the brake pedal, but on average, those systems consist of the least expensive and often least effective braking components the trailer maker could install and still meet DOT requirements. Think weak, electrically-activated drum brakes trying to stop skinny, easily overwhelmed tires and you have the recipe for the terror in a pickup driver’s mind as someone poking at their phone pulls their Jetta in front of a fully-loaded Sierra 3500 saddled with a giant toy hauler heading down a 6% grade at 50 plus. It’s not a pretty picture.
That’s why a team at General Motors decided to see what was possible if they modified the braking system on a 14,000-pound trailer with some of the same braking hardware that was slowing down the truck towing it. The results were remarkable.
GMC says their experiment yielded a stopping distance a full 40 feet shorter from 60 miles an hour from a typical setup – a 20% improvement. That’s huge – and it was from a system quickly cobbled together (albeit by engineers) as a proof of concept, so further refinements could yield even better results. “The whole project started as part of GMC’s drive to improve trailer safety,” systems engineer Todd Brinkman told Design News, where a video of the experiment shows the team hitting the brakes with a car as a reference marker for where the truck and trailer needed to stop. Stock gear resulted in the test rig passing the car – or hitting it in a real traffic situation. With the modified trailer, the assembly stops well short of any collision.
A big factor in the performance of the system is the GMC eBoost tech, which is essentially a brake-by-wire system that takes input from the brake pedal in the truck and then uses a motorized actuator arm connected to the hydraulic system – the brake pedal doesn’t actually physically activate the braking pressure. ABS tech at each wheel prevents lockup. But previous to the experiment, all that cutting-edge brake tech was just in the truck. The GMC team figured out how much braking force they needed to quickly halt seven tons of trailer and fabbed up a container for a second eBoost system on the trailer itself along with an upgrade to the running gear, including tires and brake discs. “We wondered, ‘What would it take for the truck and trailer to be able to stop in the same distance as the truck alone?’” Brinkman said. Looks like they have a pretty good idea.
As mentioned, braking systems for trailers have languished far, far behind the tech wave currently washing over every facet of the automotive world, and GMC’s experiment shows that even a modest upgrade can have life-saving results for everyone on the road. GMC hasn’t said if the system could ever come to market from the carmaker of any trailer manufacturer – but it should.
While change comes slowly to large governmental agencies, the DOT should take note and set about upgrading the braking requirements of trailers to better cleave with the modern systems in cars and trucks, and more modern trailer brake interfaces should be standard on any truck with a tow hitch. Yes, it means that truck, trailer or RV is going to cost a bit more (if only for a while), but what price would any of us be willing to pay to give pickup drivers the ability to better utilize all that rubber on the road to come to a quicker stop and avoid hitting us or a loved one?
