[Yak] RE: Tandem Brakes

[alex wetmore]

On Fri, 12 Sep 2008, Bradford Miter wrote:
> Our mid-90's Two'sDay came with a front hub brake by Sachs in addition to
> the cantilever brake.  It is quite small compared to the Arai and really was
> only intended as a drag brake.  We would use it sometimes when going down a
> steep hill but on the very steepest hills when pulling the trailer we would
> just get off and ride down the 15% decline.  We could do this in England
> where the really steep hills were usually short.

I have the Sachs brake and have owned tandems with the Arai brake
(although our current tandem has a 203mm disk instead).

The Sachs brake is not intended as a drag brake.  It is intended as a
regular brake, and doesn't have the cooling capacity to be run
continously.  The major difference between it and the Arai is that the
Arai has much more surface area for cooling the brake.  The Sachs
brake will probably just boil the grease if it is used contiously.

I have the Sachs brake (the front wheel and fork were stock on a late
90s Family Tandem) on my cargo bike
(http://www.alexandchristine.smugmug.com/gallery/5490129_zerKA#335762634_YWXVy-XL-LB). 
It works very well if it is mated with the correct lever.  You need to
use it with a cantilever or drop bar lever, not a V-brake lever.  Most
flat bar levers made today are V-brake levers.  With a V-brake lever
it doesn't have enough leverage.

With a canti lever it isn't as powerful as the best V-brakes, but it
is better than many other brakes.  I can't easily lift the rear wheel
with the drum brake on my cargo bike, but I can do it.

The Arai brake is great for loaded touring on very steep hills.  I
think that it is overkill on most tandems which don't see such use. 
For shorter but steep hills (like the ones we find in Seattle) I found
two cantilever or V-brakes to be more than enough.  I never had the
rim get too hot to touch, even after riding the brakes down 10% and
steeper grades for a few blocks.

The Arai drum brake on our tandems did it's best service when riding
the tandem fully loaded on logging roads.  Those would have many mile
long descents at 10% and steeper grades with tight switchbacks where
we couldn't get going much faster than 15mph.  The Arai would get so
hot that water or sweat would instantly boil off if it touched the
brake.  No other bicycle brakes, including the 203mm disk on our
tandem, can handle that kind of heat load.  I'd also guess that under
5% of tandems are used in such conditions...only one of the four
tandems that I've owned has been put into that type of service.

alex