I found myself looking at tandems today and was surprised to find one with 3 brakes.

Dolan TDR

A bit of further research found that a 3rd brake can be used as a drag brake on steep descents - especially when loaded. In the case of this bike, it is operated by a friction lever on the end of drops.

So my question(s) are how and when is the 3rd brake used? I'd have thought dragging a rim brake would carry a significant risk of rim overheating and blow out? And how is it operated whilst keeping hands on the main brakes?

  • 1
    Some other tandems have three brakes here one is for the stoker in the rear
    – chichak
    May 12, 2022 at 5:31

1 Answer 1


The tandem I owned had a drum brake on the rear wheel as a third option, along with a hydraulic rim brake on either wheel.

All three brakes were controlled by the captain in front only.

Normally you'd have your convention brake levers/brifters running the rim/disk brakes, and the third brake would have a control that was not immediately to hand.

On mine it was a bar-end shifter that you could move and leave at a setting without having to hold it. IE there was not enough spring tension to release the brake, the lever held the brake on. For this reason I suspect any drum brake would be cable actuated only, not hydraulic.

I hadn't found a situation where the third brake was needed, until I was solo-riding down a grade and a hard braking effort raised the rear wheel off the ground. Moving my own body weight backward was insufficient. The rest of the descent was a lot more restrained !

As for overheating, the drum brake can take a fair amount of heat before it gets too hot to work well. And then consider it is only there as a limiter, and your main brakes will be cool and ready to stop the bike.

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