|the secret to a cycle tractor is the gear reduction|
is a perfect example of how to NOT build your bike |
into a cargo bike. If they had used a motor with a high
contrast reduction ratio it would be able to climb hills
with massive amounts of weight at a legal wattage.
But most builders insist on using fast gears and
electronics to limit the speed. Unfortunately that
can be bypassed to make it a deadly motorcycle.
40 mph is way too fast for a machine like this no mater
where you ride it. And the wattage their motor uses is only
appropriate for an off-road bike. This is NOT a street
cargo-bike. It would be perfect to go camping in the mountains.
Low Gear= High Contrast Reduction Ratio.
You ever wonder why e-bikes burn out so often? It is because they are built as cheaply as possible and because people want to use them much harder that they are built for. So why can't they build them right for heavy duty use?
The controller type and setup have a significant effect on performance, not just the motor and gear ratio. Kelly controllers have constant torque mode capabilities, in other words they have the capability to prevent amp multiplication at low RPMs that increases torque as the motor gets dragged down by increased load (at the same throttle setting). This prevents wasted energy at low RPMs where the motor is most inefficient and overheating abuses of the motor.
|pedal assisted power drive|
|veloci front hub w/ two disc mounts|
|sprocket bolted on front hub used on rear|
A #35 chain to the left hand side of the drive wheel is better than a BMX chain. The hard part is figuring out how to mount a large sprocket on the hub and still keep your disc brake.
I think it would be easier to use a belt drive with a large rim pulley on the drive wheel than any kind of drive chain, unless it has a two stage reduction. I could not find a sprocket large enough for a single reduction. But a 12inch child's bike rim makes a good enough pulley for a belt. Then a 1.5” belt pulley on the motor would be close to an 8:1 ratio.
drive hub-motors even just for bicycle use are not a very good option
for true cargo hauling ability at least in my experience. For a cargo
hauling a manual transmission with manual clutch that allows
aggressive downshifting regen braking (and also downshifting for
getting those big loads moving or dragging them up hills) is a very
good idea. Why do you think the big 18+ wheel tractor trailer rigs
still use manual clutch transmissions? In-fact due to the greater
downshifting regen braking ability of electric motors compared to IC
compression braking the argument for this kind of drive system is
even stronger for heavy cargo hauling.
a controller for climbing steep hills with cargo:
to probably take a Kelly controller and set the output motor phase
end amp limits to the exact same as the battery input side amp limit.
That will give you nearly constant stable torque, if that's too low
to do the controlled front wheel pop up you desire on take-off then
slowly up the output motor phase end amps limit while leaving the
battery input side amp limit the same which in each step will
increase the bottom end torque slightly and just keep upping it in
increments a little at a time until you get the level of bottom end
torque that gives you what you want.
to carry enough battery to keep your discharge rate under 2c.
10 amp hour size, that would be a 20 amp controller and about 700
keep your self from being ripped off when choosing a battery please
read this article!
batterys are now costing about the same as lithium-ion per watt-hour
and life expectancy. I hope that lead acid will eventually cost much
more than the light weight cells; even if they do need to go to the
moon to get the lithium materials.
Fixed Gear Drives
BIG BLOCK alternative Motor (for a larger motor)
|sprocket adapter for free wheel hub|
Best thing to do is to use a large sprocket like this one and just bolt it onto a large sprocket from a used cassette, or possibly two. then use a smaller cassete for the leg powered chain.
/ how to motorize a big vehicle/ Hub Motors / How much power do you really need?