Last weekend we went to the Bentrider Online "Bent Ride 2004" in the Finger Lakes region of NY. It rained Friday and Saturday morning. Even though it was raining Saturday morning we took the bike into town for the expo. One downhill section was about three miles long. Using the drum brake to keep the bike between 20 and 25 mph, we had no problems. At the bottom of the hill you could hear the rain drops sizzle when they hit the drum brake. This was not a steep hill, just long we did not even use our lowest gear to climb it coming back. We also did not have our touring gear on the bike, that would have added another 60 to 70 pounds of weight to the bike.
Now this was in the rain so letting the bike run up speed and then grabbing a "big fistful" of brake was not really an option. 45 to 50 mph on a road I've never ridden before in the rain... Do you have any idea how hard it is to find a stoker that will ride a bike for days or weeks on end, drink warm water that tastes like plastic, eat cold crappy food, sleep in a wet tent and still wake up the next morning and do it again? With a smile on her face?
Disk brakes I myself have damaged or have seen first hand damaged by overheating when used on tandems
Formula disk brake used by Santana- warped rotor and failed brake pad.
Avids mecs with 160mm rotors as well as 203mm rotors-melted adjusters and failed bond between brake pad backing and brake pad.
Hayes mecs and hydro with 203mm rotors- warped rotors, boiled oil and pads.
Sachs disk used on the Cannondale Moto 120 fork (Ok, this brake sucked for use on a single) Everything.
I’m not saying that disk brakes don’t work, they do. Quite well when used within there limits. I would use disk brakes on a sport tandem used for day rides and club rides and off road. But a tandem for touring, or loaded touring I’m mounting a drum.
As for changing over your brakes, don’t. You cant mount a drum on your rear hub, so you would have to build a new wheel as well. Ride with the Avids, just keep in mind their limits.
"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." - Arthur Conan Doyle