Possible Electric Bicycle ? [ trolling motor ]

5-7HEAVEN

Active Member
Joined
Jun 22, 2007
Messages
939
Yeah, I was worried about that. I am not really into any of this stuff and have little to 0 knowledge on how to make this work. My thought is to have the trolling motor behind the trick and run the chain to the rear drive axle. I am assuming I will need a freewheel sprocket on the rear axle, just like what is currently there but a larger diameter. Then run another freewheel/oneway sprocket directly on the shaft of the trolling motor.

Are you saying that when I power the trolling motor it will be spinning the rear axle and cause the pedals to rotate?
You only need 1 freewheel between engine and its connecting rear sprocket.
There should be an existing freeweel between pedals and the drive wheel.
 
Last edited:


dmaxtuner_paul

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Jul 26, 2017
Messages
12
No need for a sleeve with this sprocket adaptor:

http://www.staton-inc.com/store/index.php?p=product&id=1864

Since the adaptor has no center hole, you'll need to drill the center to your specs.

Ya might as well buy cheap freewheels & sprockets from staton too.
^Great call. The threads on this were not in our guys programming, at least they were not pre-programmed in his software. I just ordered the suggested slug. Axle is out of the frame and ready for a drive sprocket to be attached. We go with a hub instead of welding it directly but either way I am limited to the size of the drive sprocket. I can only have a 5 1/2 diameter and still fit it in the frame.
 

Frankenstein

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Jun 24, 2016
Messages
5,078
^Great call. The threads on this were not in our guys programming, at least they were not pre-programmed in his software. I just ordered the suggested slug. Axle is out of the frame and ready for a drive sprocket to be attached. We go with a hub instead of welding it directly but either way I am limited to the size of the drive sprocket. I can only have a 5 1/2 diameter and still fit it in the frame.
Nice, must be fun to cut out any thread size you need from any ol' hunk of metal, something I've always found fascinating is being able to cut a hundred different uniquely sized threads in different diameters into something all with the same bit.
 

5-7HEAVEN

Active Member
Joined
Jun 22, 2007
Messages
939
What is the exact diameter of the electric trolling motor's shaft?

More than likely, it's metric.

Don't be afraid to use #25H chain and sprockets.
That's the exact size for electric scooters.

It's tiny, but this OEM size gets the job done.

In fact, I'm using #25 size for my twin pocket bike engines' gears and chains.
 

Street Ryderz

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Joined
Oct 14, 2016
Messages
3,171
I had already dropped the parts off when I saw this, but that slug would have been perfect! Nice to know it is out there. I'm sure like everyone else here, I'm half way through this build and already thinking about the next one or next revision.



This is a total spare part job. So I will only buy something if there is no way to salvage something I already have. I got the trike super cheap on craigslist, the trolling motor and battery setup are left overs from an old boat I could never get titled and the drive sprocket is off of a kids bike that got salvaged for another project. The only piece I have bought so far is the freewheel. Obviously I would have bought the slug if I could have before, but no worries, (I hope to get a pretty good deal on the custom cut one).

Also, because i don't think the trolling motor has enough torque to get this thing off the line and a real fitment issue, I went with a 36 tooth sprocket on the axle. Which is being welded on the axle Monday or Tuesday next week. The sprocket on the motor is a 16 tooth and the bike has 20" tires.

Now, I used this calculator http://www.gokartsupply.com/ratios.htm but again, I am really a rookie at all this. but the math claims a peak speed potential of 37 MPH. Which the trike can NOT handle. No suspension, the only brakes on it are a drum brake in front. If this thing doesn't burn up on the test run I will look at a disc brake setup for a rear tire. For now, the goal is 20 MPH with my ass on it, and hopefully make the battery last for 20 miles. The battery I have wont take a charge now so I may go to a smaller battery setup but for now I figure I need to get it together.

^
Sorry but thats never going to happen you will be lucky to see 6mph and then burn out the controller and or motor in ten min !A 40lbs thrust is due to the dia and pitch of the prop it does NOT put out 40 ft lbs of torque not even close! then theres the cooling issue that motor is meant to be submerged when run under load!Next is the rpm very low from 1400-2200 rpm depending on voltage and being an electric motor is meant to run no lower than 20% from the free spin loaded!Witch means the gearing you've mentioned being 2.3 to 1 you'll be lucky if it even moves!You would need a 6 tooth on the motor and an 84 tooth on the wheel just to get close to being in the acceptable limit of load and that ratio is only 14.3 to one and you will do 5.8 mph at full throttle and still be working it hard like that!If you ran that motor at 24v and 25 amps then you would have 600 watts and make more sence but that controller will not handel 25 amps continuous nor will the motor in the air!
 
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