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Converting a Gas Triumph T10 (like a Vespa) to Electric


I am converting a 1966 Triumph T10 (like a vespa) to electric. It is old and heavy.

I need advice on which motor and rear wheel assembly to buy from you.

I was thinking of 36 volts, 500 Amps motor. is that good? Can you recommend one?

Also, I am trying to use the OEM swing arm and rear wheel, which has a large v-Belt pully on it.  I can remove the pully and put on a sprocket (56 tooth?) but need it to free wheel when no engine...yes?  is there a freewheel small sprocket for the engine side instead?  I think that would be easier.

Advice and parts welcome,  thanks.

I can help you choose the right parts for this gas to electric scooter modification project. I will need a little more information in order to advise on the right parts. Having the drivetrain freewheel is not necessary. Freewheeling will make the scooter more efficient, but it may also greatly complicate the installation of the rear wheel sprocket if you are retrofitting a new sprocket onto an existing OEM wheel.

What is the top speed that you want the scooter to go?

What is the diameter of the OEM rear wheel?

Hi thank you for responding. I think it would be fine if the scooter did 25 miles per hour. The rear will is 3.5 by 8. The 8 inches is only at the very center of the steel hub the wheel is much larger. See attached photos. So a recommendation on: *motor *sprockets *voltage / amp hours *chain size Is all appreciated. When we are done picking the motor I would like help to pick the controller. I'm unsure about the breaking aspect of the controllers do I even need that? What is the brake connector do vs. The brake light. Onnector on the controller? Finally, if i use a 36 to 12 volt adapter for the lights/horn, does it chew up lots of power? Should i have a separate 12 v system with its own battery?

Here are the photos to go with last post

What is your target top speed for the scooter, and what is the gear ratio between the belt pulley and the rear wheel (how many pulley revolutions does it take to revolve the wheel one time)?


My target top speed is 30-35MPH, but a cruise speed of 25MPH for normal driving and good economy is fine.

The rear large pulley turns 5 times for each time the rear wheel turns 1 time.  There is a reduction gear built into the hub.

The small front pulley on the engine is a CVT with variable diameter.  That will get replaced by the electric motor and gear.

I did some gear ratio calculations and found that with a 3000 RPM motor and a 1 to 1 gear ratio between the motor sprocket and gearbox sprocket the top speed would be 26.8 MPH.

A 500 Watt motor only provides enough power for a top speed of around 15 MPH on flat ground. For a top speed of 25 MPH a 1000 Watt motor is needed. 26.8 MPH is around the top speed that I would recommend gearing a 1000 Watt motor for so the 1:1 gear ratio would work good with it.

If you want a 30-35 MPH top speed then a 1500-2000 Watt motor would be needed along with a gear ratio that would provide that top speed for the motors RPM.

The largest motors that we currently sell are 1000 Watts. If a 25 MPH top speed will work for you then please let me know and I will start working on a kit for the project with a 1000 Watt electric motor.

I think a top speed of 25 miles per hour is totally fine. I am concerned about the one to one ratio? Would that mean my chain would be going from a small sprocket to another small sprocket? I almost wonder if the sprocket on the electric motor should be the larger one than the sprocket on the back wheel due to the reduction gear, and make the rear the smaller one? Yes, I would like you to work up a kit for me motor controller chain sprocket batteries. I am going for simplicity, reliability and performance. I am also still trying to make the big decision about a 12 volt step down from 36 volts to 12 for the lights and horn. Do those reducers use up a lot of electricity? It would make things easier to stay with 12 volts...but i dont want to waste juice just sitting around with a blinker on using tons of battery because i am driving a reducer? Thanks!
A 1:1 gear ratio would use two identical sprockets, so if the motor has an 11 tooth sprocket then the gearbox would need to have an 11 tooth sprocket also for the gear ratio to be 1:1.

If a larger sprocket was installed on the motor than the gearbox that would increase the gear ratio and top speed, and a motor that is more powerful than 1000 Watts would be needed, but then the top speed would be higher than 25MPH also.

The DC-DC step down converters do not use a lot of power from the battery pack, they are extremely efficient and use hardly any power when not being used. You do want it to be wired after the power switch so it is not connected to the scooter when its power is off. Then you can use one without any worries about battery drain.

I will be glad to make a 1000 Watt kit for your project. Do you want the kit to include the batteries, or be without batteries? Also do you need the motor to have a mounting bracket or be without a mounting bracket?
Yes, thank you. I would like the kit. Also the converter. And yes to the batteries as well. I am not sure about the engine bracket yet, I need to see the engine and see how it would mount. I can also send you a picture it looks relatively simple.
Here are what the motor with and motor without bracket look like.

HI, thanks for reply.  I think it will work fine with the no-bracket option, if those are 4 tapped mounting holes on the face.

See attached PDF.

I am most concerned with the length of the shaft, From my mounting face I need to go out 2.5 inches to the rear sprocket.  I am looking into alternatives to remove the mounting hub on the rear wheel assembly to lessen that distance.  How long is the shaft on these engines? 

Yes they do have four tapped mounting holes on the face, and there are also four tapped holes on the back of the motor. The shaft on these motors is only 1" long. We do not have any motors with longer shafts.

Looking at the images in the PDF file I can see why the motor needs to have a longer shaft. 2.5" is a long shaft for an electric motor to have, most electric motor shafts are only between 1" and 2" in length.
Will get answer on rear wheel drive hub asap...there is a shaft in there somewhere, i will try to remove the hub so we have better dimensions for motoe/sprockets.
Ok, the rear wheel gear drive hub is not changeable. It is going to be as in the pdf I sent. I will need to modify the motor side of the swing arm to move the motor out to make up the 2 inches. I will need a sprocket for the rear that can be bolted to a flat face. Is the 750 watt motor same diameter as 1000? Lets keep moving forward with the kit thanks.

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