Tandem Drum Brakes
Tandem Safety Drum Brakes
Arai Drum Brakes

Most tandem frames manufactured in recent history are designed with clearance to accommodate a drum brake. If your frame is equipped with the features pictured above it is safe to assume that one will fit. That said, some frames are not designed with the Arai drum brake in mind. Below is a drawing furnished by a T@H regular which will simplify the process for you in determining whether you have enough room for the brake.

(Click to Enlarge)

 It is certainly worthwhile to purchase a quick release kit which allows you to disconnect the cable and reaction arm from the frame in the event of a flat tire without the use of tools. A 5mm x 25mm or 6mm X 25mm bolt secured to the reaction arm which nestles in the Pac Man hook prevents rotation during brake application. Please note that a 6mm bolt requires a very slight hole enlargement or in the alternative you may wish to run a tap through the hole.  Sometimes the hook slot may  not permit use of the shouldered bolt that comes with the q.r. kit thus double-nutting a 5mm or 6mm bolt may be required.

As pictured below, a 5mm bolt is secured to the arm by two nuts which when tightened together actually sandwich the arm.

There are primarily three types of controls and positions commonly used to actuate the Arai drum brake. First one must decide who should be in control, i.e., the stoker or the captain.

When the stoker is in control of the hub brake, the team often has difficulty communicating whether the brake is on too much, not enough or whether it should be on at all. This is compounded by the wind noise associated with rapid mountain descents. Under this scenario, the team could inadvertently lock up the rear wheel resultant of too much braking with the captain and stoker being unaware of how much braking effort the other is doing combined with the possibility of adverse road conditions.

After hearing first hand of these problems and for safety's sake, I now recommend the captain be in control of ALL of the brakes.

The captain can control the Arai drum brake by:

1) Using a Bar End shifter if STI or Ergo levers are in use.

2) Using an inexpensive Thumb Shifter when either Bar End shifters, STI or Ergo are in use.

3) Designating one brake lever for the hub brake and operating both rim brakes via one lever. This can be accomplished with the Dia Compe 287 lever designed for two brakes or via a cable wishbone or wishbone type adapter. I don't really favor this scenario as I strongly prefer to have the rim brakes operate independently of each other, especially should an emergency situation arise.  Use of the Bar End or Thumb Shifter options permit being able to control the rim brakes individually. 

     Deciding which control method is a personal preference issue.  It is easy to recommend using a thumb control mounted on top of the bar if you spend most of your time riding with your hands in that proximity. Those that ride in the drops a great deal would likely appreciate the bar end shifter.

DRUM REMOVAL

Sometimes removal of the drum can be done successfully by rolling the bike backwards while applying extreme braking pressure while someone sits on the stoker saddle. Most commonly the unit is loosened via a large spanner wrench designed for the purpose after removing the backing plate and turning the drum counter clockwise.

You will notice in the disassembled picture above that a very large nut is designed on the interior surface. A very large socket, 41mm or 1 9/16" is required. One can use a tool of this magnitude and certainly get the job done or one can purchase a spanner type wrench which is the easiest option.  It is also possible to make a tool.

CABLE ROUTING

The various tandem manufacturers have different philosophies about how to route cables and who should control the drag brake. Santana and Meridian have a cable stop on the down tube used for captain control. Co-Motion uses a cable stop affixed to the lateral tube in the stoker compartment, primarily for stoker control. Newer Co-Motions come with stops for either captain or stoker control. If you have an older Co-Motion with a stoker cable housing stop only and desire to have the brake be controlled by the captain, simply run a long housing down the lateral tube and use zip ties to affix the housing to the frame tube.

MAINTENANCE

Arai brakes require very little maintenance and they last a LONG time. If by chance you wear out a pair of brake shoes, they are available as an assembled backing plate assembly with shoes, springs and the backing plate. It is really best to replace the entire backing plate module if a problem such surfaces such as the brake failing to release. Wear takes place at the cam, the brake shoe lining and the brake shoe cam surface, all of which add up to a sticking problem after usually years of use.

If braking power is less than normal, i.e., I view normal as being able to lock up the rear wheel with drum brake application alone when no stoker is on the bike, you can sometimes improve the friction relationship by sanding the brake shoes and drum surface. Please realize you are dealing with an inhalant hazard and I have no idea if asbestos is used in the lining compound but it would be best to treat it as if that is the case.

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