Since I posted yesterday about our purchase of a tandem bicycle, many of you have asked me questions related to the mechanics of the bike and how to ride it. So, here we go.

A traditional upright tandem bicycle is like a regular single bike in many ways–two wheels (one fixed, one that steers), one frame, and one set of gears.  However, it’s obviously different from a regular single bike in that two riders supply power to the wheels.  

The rider in the front (almost always the heavier rider) is called the “Captain,” and the rider in the back is called the “Stoker.”  A tandeming pair rarely switches positions, because to properly control the tandem it’s important to have the heavier and more experienced rider in front.

The Captain’s job is to steer the bike, do all the shifting and braking, pedal and make the Stoker feel happy and comfortable.  The Stoker’s job is to pedal, assist with starting up (more on this later), and to make the Captain’s life easier (executing turn signals, looking out for traffic, handing up water bottles, keeping the bike in balance, back massages, etc).  

The Stoker has no control over where the bike is going, and in fact should actively try *not* to steer the bike–her handlebars are fixed to the frame.  Because of the lack of control the Stoker has over the speed and direction of the bike, the saying goes that “the Stoker makes no mistakes,” and the Captain should not blame the Stoker for anything that goes wrong during the ride.

Though both riders are pedalling at the same cadence, one rider is often working harder than the other.  That’s OK–the sum of the power output by both riders gets applied to the drivetrain due to the mechanics of the bike.  And since a tandem bike is only a little bit less aerodynamic than a single bike, this means that a tandem can go FAST on flat lands and on downhills, since the team is effectively getting double power with only a small aerodynamic penalty.  However, on uphills, the additional weight of a tandem usually means that a tandem has to go a bit slower uphill than a single bike.  Overall, two strong riders on a tandem bike will go much faster than the same two riders each on a single bike, even if they’re drafting very close to each other.

Both riders pedal at the same time, in sync with each other (though a small minority of riders choose to pedal 1/4 revolution out of sync), at the same cadence.  This is accomplished by the use of what’s called a timing chain, which is a long bike chain that connects the two cranksets to each other, and indirectly connects the Captain’s crankset to the drivetrain by way of the Stoker’s crankset.

Getting going on a tandem is a bit more complicated than on a single bike.  First, the Captain straddles the bike and braces it for the Stoker, who mounts the bike and clips her feet to the pedals.  Afte the Stoker is clipped in, the Captain clips his right foot into the pedals.  Once the Captain’s right foot is clipped in the Stoker (and the right foot of the Captain) applies a bunch of power to the pedals while the Captain simultaneously mounts and starts to pedal.  Once the bike gets rolling, the Captain clips his second foot into the pedal.

Some other questions that come up frequently in a discussion of Tandems:

How much does the tandem weigh?  I haven’t weighed ours yet, but I am guessing it weighs around 37 pounds with pedals and saddles, but no bottles or bags.

How much did it cost?  Tandems are expensive, with entry-level tandems costing about 150%-200% of what a single bike equipped with the same components costs.  You can’t get a new tandem of any decent quality for under $1500.  This bike retailed for $1799 last season, though I got a pretty nice discount buying the bike on super-clearance.

How fast can you go?  That depends of course on how in shape the two riders are.  However, the world record (set in 1992) for a 40 kilometer road tandem time trial is 44:18, or almost 33.6 miles per hour for 24.8 miles!

How do the brakes work?  Braking is accomplished similarly to braking on a single bike.  Some bikes (ours included) come equipped with traditional rim brakes, which work just fine under normal conditions, but on long descents there is a small risk of the brake overheating and failing.  Others come with disc brakes, which also work well, but on long descents there is a small risk of “brake fade,” or the brakes slowly starting not to work as well.  Bikes equipped with rim brakes can also be equipped with a drum brake on the rear wheel, to provide additional braking power on long descents.  On a tandem, there is no risk of going over the handlebars from the braking power alone.

If you have any other questions about tandems, please post here and I’ll be happy to try and answer them.  Also, check out the late Sheldon Brown’s amazing website, which has a great selection of articles on tandem bikes.