Bedding new brake pads isn’t nearly the chore it used to be, but it’s still a task to which paying attention is well worth it.
There was a time in the not-so-distant past when changing brake pads was a rather significant task – and changing the pads was only the beginning. Once the new pads were on came the extensive and sometimes complicated process of bedding them in. With new compounds, new chemical compositions and all-around better technology, and with the exception of ultra-long-life endurance racing pads, that process is much simpler – although still important.
“The real purpose of bedding in brake pads, regardless of the nature and regardless of the brand, is to create a uniform film transfer layer of the friction material onto the disc itself,” says Cobalt Friction Technologies Director of Advanced Materials, Andie Lin. “That’s accomplished by a combination of rotating speed on the disc and also the temperature that results from compressing the pad against the disc surface.”
It’s something best done at the track, he adds, because the way you’d brake on the road is different, even if you have a quiet country road all to yourself. Of course, if you’re driving a pure race car not registered for street use, that’s not an issue anyway. But you need to get some heat into them, and that requires some longer braking distances from higher speeds.
“With a resin-bonded compound, which is the majority of the race friction that’s on the market – ours are hybrid sintered, which is a little bit different – but for those that contain resin, the higher the resin content, the more you need to outgas it and create a char layer. With the resulting temperature from sliding and applying the brakes, you’re going to char that resin,” Lin says.
“For more modern materials, that resin content can be below 8 percent, then they become more bedding friendly. Three laps at 80 percent, bringing it up to temperature followed by a cool down to ambient is generally adequate.”
Ian Berwick, Motorsports Manager at PAGID Racing, concurs, noting that the company’s RS line, a high organic material compound, tends to bed in very easily.
“Get them up to temperature smoothly without dragging – dragging brakes to bed pads is always a bad idea, in my opinion.”
For a hybrid sintered pad like Cobalt’s, which has no resin, there’s no process to bedding at all, Lin says, and in fact some pro teams will qualify on brand-new pads right out of the box. “The second time they apply the brake pedal, they’re at full designed torque. There is nothing to outgas, and the film transfer layer only requires three to four moderate applications.”
The process becomes more complicated when a racer starts dealing with endurance racing pads – those designed to go the distance in a 12- or even 24-hour race.
“We’ve got some very long wear pads for the Daytona 24 Hour, Sebring 12 Hour, Le Mans, that really do require dyno bedding to be usable out of the box,” says Berwick. “It can take 20 or 30 minutes on the race track to bed them in because the wear rate is so low.”
The best method for bedding in brakes? Follow the manufacturer’s directions.
“For specific applications and specific compounds, it works very well to talk to us,” Berwick summarizes. “Most of the compounds tend to bed in very easily, and that’s one of the details we’re working very hard on. They bed in easily; they don’t require anything dramatic.”
One last thing to remember: Most manufacturers recommend resurfacing or replacing rotors when you switch compounds, especially between manufacturers. Check with the supplier for their specific instructions.