Norman Abbott President of OE Quality Friction explains

“Brake pads are one of the few products that have to work over such a wide temperature range,” Norm explains. “I’ll give you an example. Two cars come off the production line, let’s say built at Ford Taurus in Atlanta.

"The first car – and they’re identical vehicles, they come off the line one after the other – the first one goes north. The guy lives in Alaska, and he’s off to Japan. He’s a business man, so he parks his car in the airport in Anchorage and flies to Tokyo and comes back a month later. His car has been sitting outside – I’ve never been to Anchorage, but let’s assume it’s sitting outside – at minus 20 degrees Celsius [–4º F] for a month. So the whole car has been soaked right down to minus 20. He gets in it, and, assuming it starts – it probably wouldn’t, but assuming it does – he drives to the kiosk where he pays his parking fee. When he puts his foot on the brake, he doesn’t expect to have any peeps, or murmurs, or pulls or judders. He expects the brakes to work absolutely perfectly at minus 20 degrees Celsius.

“The next car that came off the production line goes south. This guy decides that none of his family has visited Mexico, so they’re going to get the children, and they’re going to get the neighbor’s children, and they’re going to get the dog, and the skis, and they’re going to put a boat on the back. And, oh, by the way, they want to take the scenic route, so they go across the Rocky Mountains. The car now weighs twice as much as Ford intended it to weigh, and he’s going to come down the other side of the Rocky Mountains, and his brakes are going to be running at 1,000 degrees. Similarly, he doesn’t expect to have any peeps, or groans, or squeals or judders out of the brakes. So, our product has to work over this enormously wide temperature band – invisibly to the end user.”

Therein lies the challenge. Today’s vehicles, especially SUVs, put much higher stresses on brake pads and create higher levels of heat than in years past. Yet, drivers still expect their brakes to work flawlessly – every time, under every condition and regardless of the type of vehicle they drive.

Vehicles seem to get larger every year, but because of significant increases in the performance of friction materials, manufacturers have not necessarily increased the size of the brakes. Some of the latest SUVs weigh upwards of 7,000 pounds, yet “the brakes don’t appear to be any bigger than on a 3,500 pound car!” Norm exclaims. “So that means even more so that a sub-standard aftermarket material is going to show up more quickly than it would have done historically, where the brakes weren’t used so hard.”

Now, that’s something to think about the next time your brake pads need replacing.

Article and photograph by Scott Rathburn and reprtined courtesy of CNC Machining Magazine (WInter 2001) and Haas Automation, Inc.