e-Tricycle for adults

Hi folks. I've been on this forum since 2017, so I'm relatively familiar with how eBikes work (I own 2 myself).
But I need some advice, as I am not familiar with electric tricycles.

Here is the deal. I just found out that my older sister is looking for an electric tricycle.
Her budget is between 2500 and 5000 $ (canadian dollars).

The thing is, she has a disability (she suffers from ataxia, a degenerative disease that gets worst with age). Basically, it means that she does not have a good equilibrium and can easily fall and get hurt, hence why she is looking for a trike rather than a standard 2 wheel bicycle (she is not able to ride a normal bicycle). She also becomes tired quite easily after a relatively short period of physical effort. Anyhow, she enjoys being outside and sometimes ride on a tandem bicycle with here husband. She still wants to do as much physical exercise as she can within what is possible for her (she want to keep as much physical autonomy as possible).

So she asked me to look for a e-tricycle for her as she wants to be able to ride starting summer 2021.

She is 160 cm (5'3") and weights 120 lbs (55 kg).

Desired specifications are as follow:
Range : 1 hour ride (about 30 km).
Speed : 25-30 km/h (could be faster, but she does not care much about speed)
Type of ride: bicycle paths only, with a moderate amount of hills.
If possible, not too heavy of a trike to lift
Preferred colors for the frame : orange, pink or red.

Any suggestion for a e-trike frame ???? I'm thinking that installing a kit would be much more cost effective than buying a premade turn-key e-trike.

I need to find the right donor trike. Any suggestions ?

I was thinking of maybe installing a BBSHD, but I don't know if it's easy to do on a trike.
She told me that once she gets exhausted on PAS-mode, she would like to be able to just use throttle only mode to follow here husband.

I've seen pre-made trikes with a hub motor in the front wheel, but I think these would probably be a bit unstable for her as most of the trike's weight is distributed on the rear wheels, I think the front wheel would have a tendency to spin out or loose grip in certain situations. Is there any way to mount a hub on the rear wheels ? I'd guess you need 2 motors and 2 controllers (that option seems quite complicated).

Any things I should be aware about before trying to install a BBSHD on a trike frame ??
Any frame that's a good candidate and reasonable price (Thinking that 400-1000$ is a reasonable price for the trike frame). ???
For the battery, I would like to build it for her (Thinking I would do a 13S6P or 14S6P with LG HG2 or Sony VTC4) and put it in a battery box.

Any thought are welcome. I'm in the unknown with trikes, but I would love to see my sister be able to have fun like that. It was never possible for her to consider biking as a hobby before, because of her disability, so I want to help her with that.

PS: the trike is only for leisure (not for commuting to work or for groceries). Knowing her needs, 250W would not be enough for her. 350W would be the very bare minimum. 500W or more would be ideal. Otherwise, I know some hill would be very problematic for here. Trying to balance enough power and not having a trike that too heavy (within what's possible/reasonable for a trike).

Thanks to all of you,

Matador

the sunseeker trikes look fairly easy to convert

https://www.sunseeker.bike/

goatman said:

the sunseeker trikes look fairly easy to convert

https://www.sunseeker.bike/

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Interesting ! That looks quite high tech (and expensive).
I'll look into it. I was thinking she was looking for something of this kind of shape :


Don't know if that kind of drivetrain would survive a BBSHD though (if that's what we choose to go for).

But the kind of recumbant like position of the sunseeker might have some benefits.

I'm browsing youtube to see what kind of e-trikes people have built/assembled. Basically looking for inspiration.

Matador

my sons is like the above but without the added support of that crossbar. you need that crossbar for stability. the rear brake is a coaster brake that only brakes one of the rear tires. so even at minimal speed on a gravel path decline. the tire will skid and then only one tire skids, the back right wich will want to pull you into the ditch. 2 disc brakes on the rear tires would be nice for that style trike. good luck. i wonder what Amberwolf did

goatman said:

my sons is like the above but without the added support of that crossbar. you need that crossbar for stability. the rear brake is a coaster brake that only brakes one of the rear tires. so even at minimal speed on a gravel path decline. the tire will skid and then only one tire skids, the back right wich will want to pull you into the ditch. 2 disc brakes on the rear tires would be nice for that style trike. good luck. i wonder what Amberwolf did

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Yes seem hard to work on adding a kit and have a decent e-Trike with that kind of braking system (only braking one of the rear wheel).

Matador

I aslo wonder... How does the 2 wheel in the back behave during a turn... I don't think there is any differential in the rear axle.

back tires are independent only the rear right is under power. its not like posi. 1 wheel drives

if you find a trike with rear discs adam333 makes these
https://endless-sphere.com/forums/viewtopic.php?f=6&t=51873&start=100#p1512575

if youre on a path with tree roots and one rear tire hits a root itll yank you to the side.

my son takes his to the dyke where its nice gravel pathways and its fine

Sorry to hear about your sister. Good she wants an etrike. I would like to see a a sunseeker.

The one you show in the picture is a bad pick for crank drive. It has one piece crank, so makes the install much harder. It's hard to beat the simplicity of front wheel motor for trike... Some of the biggest benefits of crank drive are centralized weight, and good climbing for the weight, but if she's not planning on climbing singletrack and hucking jumps on it, it might not be be worth the maintenance hassles. Front wheel conversion is so simple.. You could literally have it installed in under an hour.

The Schwinn Meridian trike looks like it may be a good frame candidate, and it's cheap, letting you/her spend more on the drive system and maybe disk brakes. It also has an easier than usual step-thru area.

I actually do have an electric trike with differential on the rear axle so both wheels drive, but they're not common.

I did a couple of Meridian conversions, and was surprised how flexy they felt between the front and back end, just fyi.

the best youtube video of the meridian etrike conversion is by Rinoa Super Genius

https://www.youtube.com/watch?v=P_IOnRkwa38

It’s not clear what level of disability she’s dealing with, but I thought of the Trailmate Joyrider:



That has the advantages of easy in/out, optional seat harness, and a very small front wheel that would make an easy job for a hub motor.

I know it’s available in a 3 speed version, but I expect it might be a significant machining project to set it up with say an 8 speed internal gear hub, or a rear hand brake.

999zip999 said:

Sorry to hear about your sister. Good she wants an etrike. I would like to see a a sunseeker.

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Thanks 999zip999. She has learn to live with this condition since she was very young. But it is progressively getting worst as years pass. Nonetheless, she as a strong character and is a fighter. Studied and got a masters degree and works full times, but transportation is kinda complicated.

Matador

Balmorhea said:

It’s not clear what level of disability she’s dealing with, but I thought of the Trailmate Joyrider:

That has the advantages of easy in/out, optional seat harness, and a very small front wheel that would make an easy job for a hub motor.

I know it’s available in a 3 speed version, but I expect it might be a significant machining project to set it up with say an 8 speed internal gear hub, or a rear hand brake.

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Thanks for this. Well if it can work for her, it is worth it. As to level of disability, she still walks, but with a walker. But she gets really tired after a afternoon of running errand. A bit of spasticity in the legs too. When I walk with her, I'm ready to catch her if she was to take a bad fall. Ataxia results in difficulty and maintaining a good equilibrium. Movement coordination is also impared. Physical exercice does slow progression and help maintain maximum autonomy. So I thin an e-Trike is a good idea.

Matador

Voltron said:

The one you show in the picture is a bad pick for crank drive. It has one piece crank, so makes the install much harder. It's hard to beat the simplicity of front wheel motor for trike... Some of the biggest benefits of crank drive are centralized weight, and good climbing for the weight, but if she's not planning on climbing singletrack and hucking jumps on it, it might not be be worth the maintenance hassles. Front wheel conversion is so simple.. You could literally have it installed in under an hour.

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Thanks. Taking good note of this. We don't exclude a front hub (seems much simplier indeed). I was just concerned the front wheel might spin out and make the trike less stable since there is less weight on the front wheel. I would've really preferred a BBSHD to power the back wheel, but I had no clue the fact you need a rear axle differential. New world for me... Makes the build more complicated. Seems on most trike, the pedal crank only turns just one of both rear wheels (and brake only brake one of both rrar wheels). My concern is the bike could go sideways is the powerfull BBSHD was to only power the right rear wheel without powering also the left wheel (the left wheel is free rotating, is my understanding).

The Schiwnn Meridian seemed like a good pick (aside from the fact only one of the rear wheel is driven by the crank, from what I understand). And the price is right (especially since I'm not yet sure she would like it). But now that I've seen Rinoa ginious's video where his axle sheard off, not sure I want to go cheap.

I saw this on youtube (BBSHD on a Manhattan trike) but the owner seems to say it's a solid rear axle which doesn't seem to make sense since it turn on a dime without the wheels rubbing... [youtube]rVFMQMXzwWo[/youtube]

She told me she wanted a trike after having rented a (non-electric) Azteca trike (https://trivel.com/products/azteca-2/) but apparently, starting from a stop every time felt exhausting and the seat was very unconfortable. But the feeling of freedom was amazing.



Well I clearly need to learn more about the different type of trike rear axles and cranks to sort this challenge. Man rear differential seems like the best way to go if I want even power distribution to both rear wheels from the crank and the ability to turn and be nimble. Hopefolly it's possible to find one and possibly with gears (a cassette or freewheel).

Matador

Wow ! I must say thanks to all of you. All these comments are really helpfull in my search. The speciality brake with the manifold splitter is also quite a usefull find !

The dream would be to find a trike with a rear differential and gears. That and a square tapered bottom bracket to fit a BBSHD or a BBS02.

Matador

Realistically, the main benefit of the deferential was doing zero radius turns under power with a girl on the back at parties for fun
Gears are going to be important probably since she actually liked pedaling before... They typically come so low geared on the single speeds that a motor immediately overruns the gearing.
Edit--read back a bit, you don't need a differential to use a crank drive, at steady power it's not that noticable that one wheel is driving... Same thing re. spinouts in the front, not bad except situations like a layer of sand on top of concrete for example.
But def no on one piece crank. Some frames are going to make the motor hang almost straight down, so ground clearance could be an issue.

Matador said:

I saw this on youtube (BBSHD on a Manhattan trike) but the owner seems to say it's a solid rear axle which doesn't seem to make sense since it turn on a dime without the wheels rubbing...

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It’s one wheel drive, like almost all granny trikes. Some of them use half axles and only drive one side, while others use a full width solid axle with one drive wheel and one free-spinning wheel. You might think she’ll do better with a differential, but it’s not necessarily so. I think the advantage of having one easy turning direction is sometimes more useful than having both of them be the same. And if the trike has a front wheel motor, that’s two out of three. Front drive can give you that zero radius turn in either direction.

Peerless is the old, somewhat standard differential used in trikes. It’s crude, heavy, effective, durable, and not too hard to find. Try Staton Inc. for that. You’ll find it in a limited range of inch sized axle shafts.

Samagaga is a Taiwanese (I think) manufacturer of smaller and more nicely made trike diffs, in 17mm axle diameter and maybe other metric sizes. I reckon it’s easier to find a regular trike with a 17mm axle than with 3/4”.

Voltron said:

Realistically, the main benefit of the deferential was doing zero radius turns under power with a girl on the back at parties for fun
Gears are going to be important probably since she actually liked pedaling before... They typically come so low geared on the single speeds that a motor immediately overruns the gearing.

Click to expand...

LOL! But would just one solid bar of steel connecting both left and right wheels work ? Or should the BBSHD just spin the right wheel independently and leave the left wheel as a free wheel ?

Gears are going to be important indeed. So she can find an adequate gear to still get some exercise and not just gost pedal.

I actually found a Bafang Ultra 1000W trike equipped stock with a rear diff, but quite pricy, starting at 3.5k$:
[youtube]2HxJRilo4OY[/youtube]
Matador

Another plus of how easy it is to set up a front motor is you could buy a trike and test ride it by that afternoon, and decide if she even likes the feel of the handling before sinking a bunch of install work into it. Then if she doesn't like it, easy to switch onto a potential next one, and put the first one back to stock.

Voltron said:

Another plus of how easy it is to set up a front motor is you could buy a trike and test ride it by that afternoon, and decide if she even likes the feel of the handling before sinking a bunch of install work into it. Then if she doesn't like it, easy to switch onto a potential next one, and put the first one back to stock.

Click to expand...

Great advice indeed ! Nothing is better than trying it out. Especially to see if it's confortable and stable enough

On most of them the right wheel is locked onto the axle, then the axle spins on bearings in the rear subframe. The axle pokes out the left side enough for the left wheel, that has its own bearings in the wheel, to slide on and be held by a giant nut, so it spins independently of the axle. That's a common failure point... People tend to overtighten it and crush the bearings on that side. So yes, it would work just like normal pedaling, with the left wheel freewheeling.

Balmorhea said:

Matador said:

I saw this on youtube (BBSHD on a Manhattan trike) but the owner seems to say it's a solid rear axle which doesn't seem to make sense since it turn on a dime without the wheels rubbing...

Click to expand...

It’s one wheel drive, like almost all granny trikes. Some of them use half axles and only drive one side, while others use a full width solid axle with one drive wheel and one free-spinning wheel. You might think she’ll do better with a differential, but it’s not necessarily so. I think the advantage of having one easy turning direction is sometimes more useful than having both of them be the same. And if the trike has a front wheel motor, that’s two out of three. Front drive can give you that zero radius turn in either direction.

Peerless is the old, somewhat standard differential used in trikes. It’s crude, heavy, effective, durable, and not too hard to find. Try Staton Inc. for that. You’ll find it in a limited range of inch sized axle shafts.

Samagaga is a Taiwanese (I think) manufacturer of smaller and more nicely made trike diffs, in 17mm axle diameter and maybe other metric sizes. I reckon it’s easier to find a regular trike with a 17mm axle than with 3/4”.

Click to expand...

Thanks ! That is super usefull information ! I suspected the video I posted was a one wheel drive but wasn't sure. I'm not yet sure a differential is necessary, but I want to look into it and learn about it. My sister told me she wanted to invest a substantial amount (2500-5000$ is the budget) so I understand she want a relatively good quality and durable product. She said she was looking either for an e-trike or even a powered mobility device (which go for around 6000$).

I wonder if the differential can survive the abuse of handeling the power of a BBSHD ? (I already know chain snapping can be a problem, I snapped a few myself on my BBSHD 700C hybride converted bike).

I will definitly check out your links in great details.

Matador