Hub Motor as Mid Drive - TGA Upgrade

[tongxinpete]

I have a TGA 20'' folder, an early mid drive bike with crank freewheel. The motor is a 90 degree worm drive primary (about 50% efficiency, 24v nominal, draws 35A peak & 24A normal.) This needs two 18Ah SLA's so not ideal. The rest of the bike is not bad with hub brakes. I looked into a Cyclone motor but found this unaffordable. I then found this
https://endless-sphere.com/forums/viewtopic.php?f=26&t=15704&start=300. Pic is about halfway down
What I really want to know is how has he mounted the sprocket on the motor. If bolted directly to the alu motor casing, then there is a freewheel built in to prevent pedals 'back driving' the motor?. A fixie sprocket screwed on (if a rear motor) would tend to unwind off unless somehow pinned to the casing?. I would want to go to 36v as the other stuff I have is this. Looking at about 20 Nm & 201 rpm as adequate Would give me 34 Nm in lowest S/A gear & a 6 to 15 mph range. Anyone on here who has opened any small motors - to know if there is any room to bolt through to an end plate. & if so which motor. You might say buy a mid motor kit, but these not affordable for me. (Bike rescued from the local tip, would like to re use)

 

[Deleted member 4366]

Have a look at these photos of the one I did. I sent the drive to the left side, but if you use a Q100, you could fix the free-wheel threaded part to the three clutch screws:

http://s451.photobucket.com/user/d8veh/library/Crank drive?sort=3&page=1

here's a Q100 clutch and sideplate. The clutch has three threaded holes for the screws that fix it to the side-plate. The centre of the clutch can be flipped to make it work in the reverse direction, which means that you can mount a sprocket on the disc side using the disc fixings, and turn it round to the right side; however, you might need to experiment with different controllers to run it like that because the timing might be different. I'm not sure about that. I only did it one on a Q128, which worked on the third controller, but span to 44 mph, instead of about 30 mph, which it should have been. Luckily 44 mph was exactly what we wanted:

 

[tongxinpete]

Thanks, Dave for the reply & pics, my crank sprocket (to be driven by the motor) is on the RHS so I guess I would not need to reverse the motor's present direction. I think if poss i will bolt to the side plate/clutch, thus when I pedal the outer casing only is rotated (the crank freewheel - already present - means the motor will rotate the back wheel but not the pedals at the same time. Did you find these crank drives to be the way to go vs say a Q128H in a back wheel, ie using the same money (or slightly less) to throw a few more amps as needed only on hills into a hubbie. Only really considering this because I already have a free bike.
I have a Q100 but cannot face disturbing it from the 24'' rear rim as this was my second wheel build. Might look for a used one or similar thing on ebay. Sorry it has been a couple of days in replying but we only have the one laptop.
Hoping a used hard drive tower coming my way so will be more prompt if so.

 

[Deleted member 4366]

I wouldn't say it was the way to go, but they can be a good solution for particular circumstances. My Bafang swx could drag me up a 14% hill easily without pedalling as a crank drive. As a hub-motor it was hard work to pedal up. The downside is the horrible and constant gear changing.

You must make sure your mount is very stiff to stop the primary chain from jumping.