Help! E-bike newbie with e-trike conversion project.

stueeee

Just Joined
Oct 28, 2021
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Hi to all, need to apologise first for being a newbie with a very wordy first post on here, but this does look like a good place to get right answers.

My partner needs a trike rather than a bike. After a very disappointing experience with a newly manufactured E-Trike a year or so ago (the manufacturer eventually took it back after numerous quality/function issues) my partner has purchased for fairly minimal money, an old Pashley made trike with the intention that I convert it to an E-trike for her. The Pashley needs some remedial work to make it safe/rideable in its current form; I am a retired engineer with a reasonably well equipped workshop, so doing that stuff shouldn't be an issue for me.
44552

However, beyond assembling the previous new flat pack E-trike, I don't have any experience of installing a complete electric control and power train on pedal powered stuff. At first, I was thinking of buying a powered front wheel kit for the trike, but for a number of reasons, not least there being no triangulation of the trike's headstock, I'd rather power the rear axle; there's a fair bit of space below the big metal rack on the back for both a motor and battery(s), so I thought of fitting something like this....

https://www.ebay.co.uk/itm/392835269141?hash=item5b76ce8215:g:0PYAAOSw7O9e4zLW

Obviously I'll need to fabricate new motor mounting brackets, machine up suitable hubs for a rear disc brake and probably an axle drive sprocket. The price of these E-bike setups I linked above does look rather low by comparison with a lot of other kits on the market, I wondered whether anyone here has any experience of these or something similar in form factor that would do the job satisfactorily. Some detail of the space in the rear axle area in the photo below. IMG_3993.JPG



Thanks for looking, Stuart.
 
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Nealh

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Wow, that looks like a proper barn find. An early TR-1 design.

Does it have rear brakes ?

Back pedal braking ? If so a rear motor will be out.
 

soundwave

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why do you have 50+ cans of baked beans :D
 
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Nealh

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WInd power for when battery on the conversion runs out :eek:.
 

stueeee

Just Joined
Oct 28, 2021
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Wow, that looks like a proper barn find. An early TR-1 design.

Does it have rear brakes ?

Back pedal braking ? If so a rear motor will be out.
Thanks both for the replies. There's no back pedal braking, not sure if that would have been possible with the Sturmey Archer hub gear setup the trike has -that looks to be original as far as I can see. There's no sign of anything like the small drum rear brake setup I've seen on another early trike either. The axle has to come out anyway, one of the reasons it was minimal money to buy is that in the past someone has done a "repair" so that now both rear wheels have right hand threads retaining them; obviously, one wheel keeps coming undone. I'll either make a new axle, or maybe build up the bodged thread with TIG weld, machine it back to size before screwcutting a left hand thread onto it. I'll fit a disc brake on the rear axle too; a single brake is rather scary even without electric power. Fitting a dedicated sprocket to the rear axle for a motor drive looks like a fairly simple solution to me at the moment.

@soundwave yes that's a lot of beans, perhaps we overdid it when they were on special -anyway, we won't starve in the unlikely event of a lengthy siege here;)
 
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Nealh

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One brake is illegal on bikes/trikes for road use so good job it will be remedied.
 

sjpt

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A 24v system is likely to be quite underpowered, even though still nominally 250w like other legal systems. It would probably be fine on the flat but start struggling quite quickly with any hills.

I think you might be best with a crank drive as that avoids all the tricycle specific complications, and several well respected and reliable ones to choose from.

I can see your reluctance to a front drive, though I suspect the headstock would be robust enough to take it.
 

peter.c

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Apr 24, 2018
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Crank/mid drive is fun without a rear diff corners become the stuff of nightmares :eek: a low power front hub will be a option might require a fork change. But tricycle drive parts axle disc brake kits from the UK manufactures /dealers cost a small fortune that is why they end up sold for spares, but can be rebuilt with thinking outside the normal supply chain