Brakes

When you're trying to stop a tandem, you need to have a lot of power, but you also want to be able to dissipate a lot of energy.  Let me explain.  With roughly twice the weight of a normal bike, you need to have brakes that can exert a large stopping force on the wheels to safely bring the tandem to a quick stop.  The best brakes I'm aware of are the disk brakes that most high-end bikes come with now.  But they're not all the same.  The larger the ring, the more stopping torque there is to apply to the wheels.  That's because torque equals force times distance and a bigger distance (larger ring) for the same force equals more torque.  The one concern with higher torque though is on the front fork.  The front fork must be capable of handling the higher torque without bending or breaking, which, obviously, would not be a pretty sight.

The other important consideration with tandem brakes is be able to dissipate heat during long descents with a loaded bike.  Last summer we rode Cycle-Oregon and the route went back and forth across the Cascade range north of Crater Lake.  There were several descents of 3000-4000 feet, over tens of miles.  Several times we stopped to rest the brakes, and the rings were so hot that they became discolored.  Spritzing just a little water on the rings from one of our bottles made an instant steam cloud.  The 180mm rings that our Calfee came with just aren't big enough to dissipate all the heat from long descents like that.

The largest available standard ring size is currently 203mm.  And that's where the problem lies.  Calfee shipped our bike with 180mm rings, and they're just not adequate.   We've now installed 203mm rings on front and back, and while that may not sound like much, I think it will improve things substantially.  Even better would be if Calfee adopted 240mm rings like Santana has.  That size ring would almost double the thermal mass and surface area and provide much safer braking on the long descents.