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Farthing Penny Bouquet Rock’nRoll Bike #1 2011 (click for video)
Arms
can assist pedalling for extra peak power, reduced leg muscle fatigue and
full body exercise (as in the
frontrowing rig).
The low stemhead on the Farthing
Penny due to the small front wheel
suggested a U handlebar that
would clear the bucket even when raked forward. Then hinging the bottom of
the handlebar would allow a forward and back oscillation of the straight
handle crossbar crowning the uprights.
During this rowing, steering can still be effected by opposing the
arms. Pushing against the body weight on the saddle, the
forward
stroke pulls a bridle from the handlebar uprights to a wire through a
double pulley at the side of the saddlepost to a chain around a BMX 16T
‘Southpaw” left-handed freewheel on the left side of the rear wheel. The
dead end of the chain is tensioned by shockcord through the pulley from the
stemtube. The Kevlar bridle’s ‘larkshead’ loops can be shifted up and down
the uprights to change the armpower gear.
The key control mechanism is a pin
which is sprung into a plate with an arc of holes to lock the handlebars in
various fixed rakes and for support during braking. It is unlocked by a
Bowden cable when the rear brake lever is held open beyond a limit set on
the rear caliper opening. As soon as
the right fingers stop pushing the lever wide open, the spring locks the
handlebars for support. The locking pin engagement in a hole will be
visible for extra safety
The arm-pumping gives a welcome boost to keep
the mean speed up and avoid downshifting on grades and gives a whole body
workout. Exhaling hard in the
forward push achieves synchrony of the two chest-tightening actions.
The placement of the handgrips in front of the uprights protects the
hands inside of the uprights and
narrows and compacts the bike for less windage, safely sharing
narrow paths with pedestrian and easier storage. Dangerous bottoming out of the brake
levers, and snagging by the levers and handlebar ends are all eliminated..
Besides locking at forward rake, one can crouch by holding the handlebars
at the bottom of the U. This,and carrying cargo in 1 hand needs a backpedal brake for safety
The shockcord tension springs the steering back to center which
stabilizes it for riding no-hands to start a clothing zipper or for leaning
the bike to rest. The Southpaw engages as does my backpedal
brake so the rear wheel can’t be backed up, which does allow
resting uphill against a wall. Or the handlebar bridle disconnects easily for high street
shopping and very easy mounting by swinging the leg forward over the low
frame behind the handlebars.
The design is easily made into a folding bike; conversely a folding bike is improved by backpedal braking,
armpower, and bucket cargo,
Most hubs are about the correct
diameter on the left hand side so lefthand threading with an improvised
adjustable “tap” die avoids tedious unspoking/spoking. In the 1.375”x24tpi
LH die the .330” tap holes are evenly spaced on a circle of 1.705”. They
are tapped with the same the 3/8-24 right hand tap through a faced nut
vised against the plate and progressively rotated 120 (2 corners) clockwise
in clockwise succession. The die can be adjusted by locknutting the taps so
their cutting edges are not quite radial to the big circle. It is best to
have the freewheel and remover in hand to test tightness, and especially
since the Southpaw is already a special order.
30 years
ago I direct drove a
rear wheel in the front forks from cranking handlebars with a big
sprocket, but no front load could be carried especially
on the frame and a chest pad was
needed for the return power stroke.. The parting thought then was that a
ratcheting motion might be a simpler way of achieving the large stepup
required for such arm motions and better synchrony with breathing, At that time I bought a Shimano FF
chainwheel (since discontinued) and as put on the left hand side as in the
photos this ratcheting chainwheel can alternatively be used to connect the
arm chain on the left side through the cranks to the normal right hand
drive chain and gearing. But then (armpower only and) backpedal braking is
impossible.
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