Two speed gear box for e-cargo bicycles?

[Hugh-Jassman]

I think it will be up to you to build one of these retro reversible gear boxes for a large cargo bike. Maybe a long box bike that can drive 450lbs total combined weight up your steep hills in Vancouver. I still have not found one of these retro gear boxes that has actually been built.
Epicyclic retro-direct 2 speed transmission

With 7500 rpm output you will need a lot more gear reduction (like 13:1 total) to keep it down to about 13mph on a 9% grade. I don't know what the long road grades are in the hills there, but probably not more than 10%? but even that would be quite a low gear with Canadian legal power.

Maybe it can be done with two motors, making it illegal only when you need to turn on the second motor. Never being able to drive over the speed limit on flat land should be taken into account by the laws.

 

[mechhead]

Here is an idea that is pertinent as it seems to me to be the holey grail of motor designs for a single stage reduction with the benefit of variable ratio transmission and full rpm on the main drive motor from zero speed, enter the dual motor planetary transmission previously mentioned by Crossbreak using a bafang bpm hub and a rotomax as the power motor belted down to drive the shell of the bpm hub motor it has the advantage of no freewheel regenerative breaking and variable ratio . here is a paper about it but there are other ways to impliment it like crossbreak mentioned in the thread here:

https://endless-sphere.com/forums/viewtopic.php?f=28&t=49929&start=25

and the paper about a singly integrated unit that uses a ironless brake motor to give nealry lossless frewheeling and regen

https://www.podbike.com/downloads/Full-10.pdf

 

[mechhead]

Or you could try the razor scooter twospeed transmission it would probably work well on a large cargo bike where there is room to fit such a thing


https://www.google.com.au/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjruuirtInZAhVKNrwKHVgcDXIQjRwIBw&url=http%3A%2F%2Fwww.xtreme-toys.co.uk%2Fevo-petrol-scooter-chain-drive-2-speed-gearbox-transmission.html&psig=AOvVaw31jTVwlh2bL8wVpHuYKw6Z&ust=1517735727589809