The brake still has significant material, but worn down such that the thing (cam?) that separates the shoes rotates past the working position does not further separate the shoes, causing some loss of braking power. The brake has 50K. Our weight with bike, gear, and us is 450 pounds. Long mountain descents really heat up the brake. Some years back when biking the Skyline (Shenandoah) and coming to a rest stop I sprayed a bit of water on the brake, it sizzled...could have cooked an egg on it. Same for some Rockies rides. I trust this brake with our lives...it would take sometime to reach that confidence level with rim + disk brake. I feel another rant coming on about disk brakes on a tandem.