Originally Posted by phinney
No travel agent on the Cannondale's and I don't see how a Travel Agent would be any benefit. There isn't enough lever travel to add more leverage but there is enough lever travel so no more is needed. Maybe the Burley uses the off-road Avid caliper?
Yeah, I'm kinda struggling with this one too...
If Team Godzilla, aka. Kip C. or perhaps Tim P. is reading please chime in, but to the best of my knowledge none of the Avid's that our friends are using on their road tandems-- to include a new as of July 4th Weekend Burley Rivazza -- has needed any brake boosters.
The only thing that I can think of is that some dealers are finding it easier to set up the brakes and to eliminate any initial rotor drag** by leaving more room between the pads and rotors than intended and using the cable booster to pick-up the slack. This would certainly work and probably provide quicker brake actuation with less lever travel. I guess if you don't mind introducing another moving part into the brake cable system and the associated aesthetics of the devices, there aren't too many downsides to the use of a booster.
My approach to addressing the nuances of Avid disc installations on the rear wheel of a tandem remains the use of a supplemental return spring between the caliper's cable stop and torque arm. Instead of increasing the total amount of travel used to actuate the torque arm and caliper's pistons, the supplemental return spring helps the built-in spring tension adjuster by compensating for the added drag that comes from a tandem's long rear brake cable run. This method of pre-loading the torque arm simply aids in piston retraction by relieving some of the cable drag that pulls against the torque arm as well as providing a slight improvement in lever feel.
Ultimately, it's whatever works best for you and your tandem dealer / mechanic and if the addition of a travel agent makes your tandem's rear disc brake feel better that's all that matters. I'll have to keep my eye open for someone who is riding a C'dale or Burley set-up by Mel at the Southern Tandem Rally in October to see how the TA has been integrated into the system.
** Rotor Drag is a slight rubbing that sometimes occurs between the disc rotor and brake pads. It is not uncommon with a new disc that hasn't been used to see that it is not perfectly true. However, the discs will normally straightened themselves out during the initial break-in process.