Paul "Butch Cassidy" Newman, who performs his own bicycle stunts, advises that it is too late to put on the brakes once you're upside-down, but a set of Sturmey-Archer drum brakes will stop your bike, and easily toss you over the bars if used haphazardly! I was so impressed that I bought a pair (drum brake hubs) front and rear for an old Raleigh Gran Sport. No maintenance, clean rims, weather-proof, large strong flanges—Cool!
The standard supplied brake levers for the hubs are JUNK, however. They are nylon, are flexible and have limited travel. As far as I'm concerned, they're unsafe and non-functional. We have sold hundreds of the old Pashley Roadsters with these brakes, front and rear, coupled with mountain bike levers with Zero complaints. My personal bike had Campagnolo Record road levers and, again, you can easily lock-up both wheels, but they have better modularity than linear-pull brakes. Linear-pull and disk brakes require less hand pressure to lock-up the wheel than the SA drum brake, but you have to wonder if being able to easily lock-up a wheel is a good thing.
Braking at the hub will make for a bit more spoke stress than rim braking, but since drum brakes have better modularity than disks they will stress the spokes less. Rim brakes are less stressful to the spokes than drums or discs. I suppose it is a proportional game (or caper if you are a KiWi or Oz resident).
While it worked, I found that, for me, the Aria Drum Brake lost it's effectiveness quickly with use. I preferred the Canti's, with good pads on mine. While not designed for a tandem, I have never had any problem with the newer (since about 2000) Sturmey-Archer drum brakes. They have primarily had alloy 90mm hub shells but as I recall the steel ones worked fine.
Set-up with the Sturmey-Archer is a non issue, really: Adjust the bearing, clamp the brake-reaction arm down, use decent brake levers, quality cables, take slack out of cable, apply pressure to handle, stop. I feel like they are as simple as you can get.
Good, well placed cable-stops will help any brake. Santana Tandems going back over twenty-five years have some of the best, and had big cables in the old days.
Yours in Cycling,
North Road Bicycle Imports
P.O. Box 840
166 Courthouse Square
Yanceyville, NC 27379
toll free: 800-321-5511