Better brakes mean safer trucks
Industry working on pads designed to increase friction and reduce accidents
After taking time off behind the wheel last year, I came back with a fresh outlook. I find myself looking at this industry from a whole new perspective, and I like what I see. Especially the equipment on the roads.
Big commercial rigs always seemed, to me anyway, to be the last to “get with the program.” Last to come up with the latest and greatest mechanical breakthroughs. And no, I am not talking about electric vehicles.
Instead, I find myself thinking very carefully about one aspect I had never really given too much thought to: brakes. Mixing and matching. Drums and discs. Sure, we’ve had the discs on the front, drums on the rear of cars and pickups for longer than I care to remember. But loaded rigs?
The biggest test comes when a loaded unit is rolling down a hill, or a long grade. The old-fashioned drum brakes will heat up quickly and start to fade. When that happens, the discs will take on a bigger share of the slowing down request of the system, and so, will wear down faster than the drums. The discs will generate more heat from the friction, and the disc pads will wear down at a much quicker rate.
This will be especially noticeable when the tractor has drums on all axles while the loaded trailer has discs on all its axles. The trailer brakes will end up doing most of the stopping power, and will wear out faster than the power unit.
That imbalance will be even more noticeable when the power unit is all disc brakes while the trailer is old-fashioned drums. The power units brakes will be trying to stop that loaded trailer, and at the same time, the trailer will eventually be pushing the tractor and making the situation somewhat dangerous for anyone nearby, especially the driver.
This mix and match combination now puts a bigger onus on the driver. It becomes a very important maintenance situation.
If the drum brakes are not maintained and set up with proper adjustment that allow for brake shoe travel and stopping power, the disc pads will take over, heat up and wear out faster than expected.
Then, hopefully, there’s a run-away lane the driver can aim for and hope to live to tell his story of shoddy brake adjustment in his pre-trip inspection. One more braking news story … Here on the Wet Coast in 2010, California and Washington politicians enacted legislation that requires all sold and installed brake pads to contain reduced levels of copper and heavy metals. The thought being that as the pads heat up and wear down they deposit the copper and metals on the roadway. Mother Nature then washes those deposits into nearby streams and rivers, into the little fishes, and into our food supply.
Problem is that copper is one of the key elements used to manage thermal energy, and since disc brakes operate at higher temperatures the copper stabilizes the coefficient of friction. With our rigs, brakes are used at various speeds, temperatures and application pressures. Bottom line: copper saves lives.
Now the brake manufacturers are slowly getting up to speed in trying to reduce that dependency and still being able to deliver a pad that will meet the demands of the driver and the politician.
It’s said to be a four-year procedure to come up with that reduced level of copper because of the extensive testing of metal and fabric mixtures that will deliver required friction.
Then, too, the cost has to be kept down so the trucking fleet owners and even the single rig owner-operator can afford to buy and install the newer pad. Changes are happening. Above all, I want my brakes to be there when I need them. Don’t you?
I could fill a newspaper with stories about life on the road, but why not share yours? Send them to Driving editor Andrew McCredie at amccredie@postmedia.com.