Rubbee X e-bike conversion kit


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2:09 PM
Jul 28, 2020
Hi guys !

Gediminas from Rubbee here.
Some of you might heard the Rubbee name before.
We design and build friction e-bike conversion kits.
We've just introduced a new version called Rubbee X, here's the intro video:

What do You think?
We have customers who use our previous versions for going up the MTB trails after going downhill :cool:
Just want to get some community feedback, you can learn more at

Feel free to ask, I can give a lot of insider info :)

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Will it attach to a dropper post? How will it work with knobby tires? Will this device turn a normal mountain bike into a class 1, 2, or 3 bike? How is it supposed to work with bikes with full suspension? Is this legal to use on multi-use trails where motorized vehicles are not allowed? What happens when I go over rocks or take 4 ft drops?
Clean design, nice features. Reasonable Kickstarter price too!

Seems like there might be an urban niche for it; doubt that it would be of much use for serious MTB'ing.

I think it would have problems with wet/sand/mud and the range of tire treads/pressures. Can't see how it could work well with generous rear suspension travel.

But even for urban use; what about those ubiquitous rear racks?

Did you consider a design for front wheel placement?
Since a friction drive relies upon friction (duh!) anything that reduces friction is a bad thing. Like rainwater, mud, sand, etc.

There is a reason why there has never been a widely sucessful friction drive. Even Solex, who made a fwd gasoline moped version couldnt lick the slippage problem and eventually went under. For a few years though, they were everywhere in France as they recovered from the War and people needed the very cheapest transport.