Tech Tip: Aggressive brake drum friction

Bendix advises spec’ing drum brake friction in line with your gross axle weight rating.
Dec. 14, 2017
Wx Anj Tu D 5a54f5307abce

Myth: More aggressive drum brake friction will last longer .

Fact: It’s possible that drum brake friction meant for a higher gross axle weight rating than your vehicle’s may last longer, but it will also likely cause more drum wear and shorter drum life. And because it may provide more torque output, it could lead to problems with brake imbalance.

Bendix advises spec’ing drum brake friction in line with your gross axle weight rating. There may be instances when a different friction is called for, but normally you should use the same rating as the axle.

“Some people are tempted to spec a 23,000-lb friction on a 20,000-lb axle, for example, figuring it’ll stop better and last longer,” said Kevin Pfost, Bendix Spicer Foundation Brake (BSFB) product specialist and longtime master technician. “That’s not always true. Just because the friction is more aggressive, doesn’t guarantee a longer life. Think twice before doing this, because more aggressive friction will often wear your drums more quickly. And the friction could potentially be hard enough to crumble when it starts to heat up.”

Information provided by: Bendix

Sign up for FleetMaintenance eNewsletters
ID 2543266 © Michael Emerson | Dreamstime.com
dreamstime_xxl_2543266
While 2025’s Brake Safety Day’s focus was on drum and/or rotor violations, the most common out-of-service violation was the 20% Brakes criterion.
ID 161494674 © Dmitry Kalinovsky | Dreamstime.com
dreamstime_xxl_161494674
A recent Iowa incident proves the potentially deadly consequences of wheel-off events, highlighting the need for torque checks.
ID 2543263 © Michael Emerson | Dreamstime.com
dreamstime_xxl_2543263
Brake Safety Week is coming up at the end of August, meaning that fleets, drivers, and technicians need to make sure their vehicles are prepared.