E-bike
Side Stand Safety
Side-stands are hideously dangerous; but it is often difficult to fit a
pedal bike with a centre-stand, and the presence of a mid-drive motor
in the bottom bracket blocks one of the best mounting points. A
side-stand is
therfore usually the only practical option; and the business of
remembering not to ride-off with it sticking-out depends on the terror
engendered by some previous occasion of having done so. Just as modern
motorcycles don't allow the engine to run with the
side-stand down however; it is possible to make a safety
side-stand for e-bikes by incorporating a switch to short-out one of
the brake inputs and thereby disable the motor. Failure to
retract the stand
is then immediately obvious when pulling away, particularly if a twist
& go throttle is used during initial acceleration.
Unfortunately, although some commercial e-bikes might possibly have a
stand safety-switch, at time of writing (July 2020), there are no
commercially-made retro-fit side-stands with such a switch.
Obtaining a safety-stand therefore becomes a matter of modifying an
existing stand, or making a new one, until manufacturers see fit to
supply this potential market.
There are actually two main types of after-market side-stand for pedal
cycles. The cheapest type simply clamps around the lower tube of the
rear forks on one side, but has the tendency
to rotate about the tube. This means that it requires some
kind
of rubber protector to prevent it from scratching the paintwork, and it
will need frequent tightening and readjustment to keep it in the right
position. The
better type is sometimes called a 'Delta stand,' because it clamps
across two
frame
tubes and so forms a triangular shape, like the capital Greek
letter Delta.
Of the two types moreover,
there is a further
division depending on the method used to lock the leg in either the up or down
position. One variant has a detent spring concealed within the
casting (see for example
the
Robesbon Sidestay). The other
variant has a spring and a collar
around the stand leg (see for example
Hebie
Rear Stand 671). The external detent spring unfortunately
obscures the obvious position for a switch actuator attachment..
When I first built e-bikes, I used single-clamp side-stands because I
didn't
know that the Δ-type existed. The stands I
bought had internal detent springs however, and so were
relatively easy to modify. Shown below is what I devised for the
Saracen Tufftrax 29.
Stand in the 'up' position.
Switch shaft retracted (open circuit).
Stand in the 'down' position.
Switch shaft pulled out (contacts closed).
View showing how the stand clamps
around the frame tubes.
I made a mounting plate out of a length of 10×50mm aluminium
bar, with milled recesses at the back to make it register positively
onto the upper and lower rear-fork tubes. Thus the new
arrangement has become Δ-stand. The mounting plate also replaces
one of the clamps of a pannier rack, which is a permanent attachment
to the bike (it carries the rear lights, and can be fitted with a pair
of
Ortlieb Back-Roller Classic panniers).
The original inner part of the stand clamp is still used,
compete with supplied rubber paint protectors, longer screws being
required to allow for the additional thickness of the plate. The
original stand bolt-holes are also used, but three additinal
countersunk screw holes have been drilled so that the stand can be held
onto the plate with M3 screws. This allows the assembly to be removed
from the bike without it coming to pieces. The switch is a Honnoh
'universal' motorcycle rear brake-light switch, the same as was used
for the
brake levers. It is attached to a bracket screwed to the mounting plate, and connected to the
stand leg by means of the supplied spring. A small block of aluminium
is bolted to the stand leg and protrudes over the pivot point. This means
that the end of the spring moves over a small radius as the stand is
extended, thereby avoiding excessive stretching when the switch is
operated. A small pillar with a top washer is screwed to the block, and
the spring is wrapped around that. As was done with the brake switches,
the end ot the spring is formed into a loop by means of a brass insert
taken from an electrical connecting block. The original zinc-plated M3
grub screws have been replaced with stainless A4 Allen screws to
prevent corrosion.
In order to incorporate a safety stand into an existing e-bike setup,
the wiring required does not need to be sophisticated. A simple Higo
Mini B3 Y-piece adapter would allow it to be plugged into one of the
Bafang brake kill inputs, in parallel with an existing switch, without
the need for any technical skill on the part of the installer.
© D
W Knight 2020
Last updated
2020-Jul-19