ADDING A DISK OR DRUM BRAKE TO A TANDEM

January 2, 2006

    My wife and I ride our 1998 Cannondale RT3000 tandem almost exclusively. It came with Magura hydraulic cantilever brakes—one of the reasons I chose the bike, especially since we ride in the Pittsburgh region, with very steep climbs and fast descents.
    In most circumstances the Maguras are OK, but I'm often squeezing the brakes as hard as I can, and barely slowing down.
    The rear hub is a Phil Wood with threading for a drum brake. I've never been enthusiastic about drum brakes, especially since they were replaced by disks on cars decades ago. I remember how drum brakes used to fade terribly!
    I'd hate to give up my Phil Wood hub. Is there a way to screw on an adapter, so that I could install a disk rotor on my rear wheel, then attach the disk caliper to my rear frame triangle? I've read good reviews about the new cable-actuated WinZip brake that Santana has adopted for its tandems.
    By the way: From time to time we load up the tandem with front and rear panniers, a Bob trailer, and head for the hills—this summer it'll be the Rockies from Missoula, Montana to Denver, Colorado. Loooongg hills!

Bob H.

    Let’s add up the downhill momentum, Bob: two bodies, a tandem, four loaded panniers, trailer . . . Have you seen the parachute NASA uses on the space shuttle?
    Seeing as I don’t tandem (on bikes, anyway) I consulted Chicago tandem expert Kevin Womac of Boulevard Bikes. He sez nix on the disc. “The frame, when built, has to be set up for disc brakes,” Kevin says—and retrofitting an existing frame would likely cost more than the bike. You’d probably have to hire Hephaestus.
    Kevin assures me that your drum-brake fears, like the reasons for a certain recent Mideast occupation, have no foundation. I’ve gleaned that some think that the aluminum in drum brakes indicates their weakness. Not so. Kevin says the mechanism uses aluminum just for the cooling surface, not the brake itself. He says it’s a little heavy (like you care about that), “but it can heat up without melting down.” Wish I’d said that.
    A neat trick that Kevin suggests: Attach the drum brake not to a brake lever, but a shift lever. So during a descent you can put the brake on partway on and leave it that way without having to squeeze the lever. This'll free your hands to use your cantilever brake levers—or release the parachute.

Mr Bike

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