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Discussions Question and Answer Forums Electric Scooter, Bike, and Go Kart Built From Scratch Forum

Home made

I have a home made project where I built a frame and put 2- 10 speed bicycles on each side with a bench seat in the middle between them. It rides 2 people side by side and both can peddle their side independent of each other. It still needs help going up hills. I need to know what size motor and controller that would be powerful enough to power this thing with 2 grown adults in it. I built a shaft so I can put any size sprocket I need. Thanks for your help.
If you want to use the electric motor to help with going up hills then it would probably be best to gear it low so it has a lot of torque to maximize its uphill pulling power. One of our 36 Volt 600 Watt gears motor would be a great candidate for this project.

I can run some gear ratio calculations and see what size axle sprocket is needed for the project. So I can run the gear ratio calculations do you know what size tires are on the bike?
The bikes have 26 inch tall tires.
I ran some gear ratios using our MOT-36600G gear motor and a 26" tire which I will post below.

The 3.6:1 gear ratio with 10.35 MPH top speed would be a good choice if you want the motor to help power the bike up steep hills, and the 2.4:1 gear ratio with 15.52 MPH top speed if the hills are gentle.

If you want the motor to power the bike up hills without pedaling then I would choose a lower gear ratio like 5:1 which would have an 7.45 MPH top speed. The sprocket on the MOT-36600G motor works with either #41 or #420 chain.

I can help with making a kit of parts for this project if you would like. Please let me know if you have any questions.
Sorry it took so long to get back to you. Yes I do want the motor to propel the bike up the hill. We are talking about around 400 to 500 lbs with bike and 2 riders. It would be great if you could put a list of parts I need to purchase for this project. You have been very helpful. Thank you.

I can definitely put together a list of parts for the project. For a 400-500 pound vehicle to climb hills with the 650 Watt gear motor a 5:1 gear ratio would be best so the motor puts down a lot of torque to the wheels. There are a lot of different battery sizes to choose from and the size of the battery charger depends on the size of the batteries. The larger the batteries the more ride time the bike will have. So I can help you choose the right size battery pack, how much ride time do you want the bike to have when it is being powered by the motor?

It doesn't need to be very long I would think no more than 30 min if that's possible. I hr would be ideal. A lot of the times it will be peddled until she needs help with a hill.
For a 30 to 60 minute ride time with the motor on I think that three 22Ah batteries should do the trick. I can start working on the kit. Would you like the throttle to have a key switch built into it, or prefer a key or power switch that is not on the throttle?
Built in would be nice.
I was just about ready to put together a kit and then I realized that you probably want to be able to pedal without the motor being on which would require a freewheel on the rear axle. Do you want the bike to be able to freewheel when the motor is not on?

If you do want it to freewheel then I will need to figure out the right parts for that. Do you know what size the rear axle shaft is?
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