Non mid-drive && non-hub setup (Cheap)

[ebikealltheway]

This is my first post so if I miss some rules or norms I'm sorry.

I've been building my "cheap" electric bike since 2013 and I need to finish this. It's a standard trek mountain bike 26" and all that, with a frame triangle bag to hold the batteries and controller, 48v 16A/h, uses a simple scooter twist throttle a scooter controller from tnc.

Here's where it got tricky, I wanted cheap and I didnt want any kits, so I bought the currie izip rear wheel that has both right hand threading on the hub for the 7 speeds and left hand threading on the left side for what comes with a 20t freewheel that I replaced with a lefthand freewheel and bolted a 80t sprocket to. Then after fiddling for about a week I decided to put my 1020MY 48v 1000w unite motor on a rear cargo rack above the rear wheel. Using #25 chain I drove the 80t sprocket with the motor fine and without any crazy adapters or diskbrake mods I was able to pedal and use the motor with no interference. IT TOOK MONTHS to get the tension right so the chain would stop falling off the drive sprocket but after riding it a couple blocks and it stayed on i wanted to get my top speed, at about 27/29mph the chain fell and caught in the wheel (for pictures referred to as wreck), not fun . Finally i bought a tensioner and it worked for about 2 (15) minute ride sessions on a open field. I thought everything was good and dandy when riding it home from the field, on the road, the chain fell off and got caught in the wheel again, I am so sick of the chain falling off and I don't know what to do. My next attempt will be to use t8f or 8mm chain from motor to the rear sprocket.. if i can find one big enough...

any advice on my design/motor location would be much appreciated

- only thing missing from this setup is the added tensioner

- only thing missing from this setup is the added tensioner
This is what keeps happening

Some field riding
[youtube]K1eUBtZIA1s[/youtube]..im sorry my dad cant film to save a life.. and my tires were like 10psi so i was going slow as hell

Thanks for your time

 

[spinningmagnets]

The rear cargo rack is flexy. When the motor is powered up, it pulls to the left, and the chain alignment goes off. You need a chain guide on the slack side of the chain (front?). Lay a plate across the chain-stay and seat stay, maybe 3-inches by 10 inches rectangle? (experiment with cardboard to find the size and shape) with U-bolts holding the plate onto the stays. the upper tip of the plate should cross the chain right where it feeds into the front of the sprocket.

Attach some type of plastic rubbing block, or even a roller onto the plate so that it occasionally rubs against the outer edge of the chain (not touching when un-powered, but very close). The motor will pull out a little to the left when its on, but the chain guide will force the last few inches of chain to align straight onto the sprocket.

 

[amberwolf]

You can also take a look at Eric Peltzer's similar early design:
http://www.electricycle.com/ebike3.htm

and then his later version:
http://www.electricycle.com/index.html


or if that's down:
http://web.archive.org/web/http://www.peltzer.net/ebike/


for some of the stuff he did and why; might help you fix up some issues.

 

[ebikealltheway]

I have struggled for quite a bit of time and money trying to find a good way to mount such a large and beast of a motor, it is the one with mounting brackets, but so far keeping the motor on a rear cargo rack has ended in two wrecks.. the goal is to get this thing on a mountain bike, if anyone knows any good bikes or ideas please comment!!!!! I have a 1:8 gear ratio with a left hand free wheel setup currently.. the hardest part is just damn motor mounting

 

[ebikealltheway]

I have struggled for quite a bit of time and money trying to find a good way to mount such a large and beast of a motor, it is the one with mounting brackets, but so far keeping the motor on a rear cargo rack has ended in two wrecks.. the goal is to get this thing on a mountain bike, if anyone knows any good bikes or ideas please comment!!!!! I have a 1:8 gear ratio with a left hand free wheel setup currently.. the hardest part is just damn motor mounting... this motor is large af.. mounting suggestions?????

 

[amberwolf]

Have you looked at any of the suggestions already provided?

If so, and they can't work for you, tell us why not, exactly, so that we can suggest something different.

 

[Mongo1]

Hi,
You may need to move the motor inside the frame triangle for stability. I'm using the same motor (without the bracket) but added a transmission to mount it the way I wanted.

 

[ebikealltheway]

Hi,
You may need to move the motor inside the frame triangle for stability. I'm using the same motor (without the bracket) but added a transmission to mount it the way I wanted.

Could you post a link to your transmission box / your post about it..that's what I've been looking for but didn't know how to overcome putting it inside the frame ! Much Appreciated

 

[Mongo1]

Hello,
Actually, I built the x-mission myself (something I've wanted to do for a while). The box is a electrical conduit box from Home Depot and x-mission parts are from mcmaster.com .

View attachment 1

 

[ebikealltheway]

Hello,
Actually, I built the x-mission myself (something I've wanted to do for a while). The box is a electrical conduit box from Home Depot and x-mission parts are from mcmaster.com .

View attachment 1

What tools did it require to assemble..as soon as I'm out of a sling I'm making one!

 

[ebikealltheway]

Hello,
Actually, I built the x-mission myself (something I've wanted to do for a while). The box is a electrical conduit box from Home Depot and x-mission parts are from mcmaster.com .

View attachment 1

What tools did it require to assemble..as soon as I'm out of a sling I'm making one!

What chain type did you use as the drive chain and what was your final gear ratio?

 

[Mongo1]

I used a #41 chain. There's no reduction in the gearbox. Rear chain ring allows 7 or 8:1 reduction. I've learned alot since that bike (built it before I became aware of this site).