8am-5pm Pacific Time Monday-Friday
Start a new topic

Convert 3 wheel bike to electric

I have a Schwinn Meridian 3 wheel bike I would like to convert to electric with enough power to operate off road with fat tires, what would I need ?  I looked at some of your motors and thought this might work , 600W Geared Motor - 36 Volts (Style: MY1020Z3) am I on the right track ?

Yes you are definitely on the right track with using a gear motor. I found a photo on Photobucket of a Schwinn Meridian bike with a 450 Watt electric gear motor attached to it.

It should be as easy as attaching the motor to the frame and sprocket to the axle and putting a chain between them.

The 36 Volt 600 Watt gear motor is more powerful than the 450 watt gear motor in the photo. It is also tougher and larger than the 450 Watt gear motor and able to dissipate more heat so it would be better for off road use than the 450 watt gear motor.

If you have a target top speed that you would like the bike to go then I could run some gear ratio calculations and let you know what size axle sprocket would be needed to achieve that speed?

Thanks for your quick reply, I would like to get 20 to 25 mph, but my main concern it torque for off road. I also would like you to recommend what I need to operate the system , from the twist throttle handle , wiring, controllers, key switches, fuses, motor if there is a better one then I picked out and batteries.  Also fatter tires and rims ?

As the bike travels at faster speeds the wind resistance exponentially increases so the power that is requires goes up very quickly. I ran some calculations and found that with a 600 Watt motor the top speed on flat ground is limited to around 22 miles per hour. If it was geared for a 22 MPH top speed it would have a moderate amount of torque but not a lot. At 22 MPH gearing if the bike and rider weighs 300 pounds it should be able to go up a 10 degree incline at around 6 MPH. Any steeper of an incline and the motor would run too slowly and risk overheating. For off road riding I think you might be better off with a 15 MPH top speed gear ratio. This will provide a lot more torque and the bike would be able to climb steeper inclines. The gear ratio is decided by the rear axle sprocket though so it could be changed by installing a different size axle sprocket if you are not satisfied with your first gear ratio choice.

For fatter tires and rims I recommend checking with local bicycle repair shops. If the parts are available they will be able to lace wider rims onto the wheels and install wider tires.

I can recommend, and if you want even make a pre-wired kit, out of the electrical components for this project. I can also calculate the gear ratio and let you know what size axle sprocket is needed for a certain top speed. I need to ask a few questions first in order to make these recommendations:

  • Considering the information I posted above, what is your new target top speed now?
  • Do you want the twist throttle to have a battery meter and key switch on it?
  • How many minutes of ride time on flat ground do you want the bike to have?

Please let me know if you have any questions.

As before thanks for the quick response , top speed of 15 mph would not be bad. Yes , I would like a battery meter and key switch , does this come on the twist throttle or are they separate ?  I would like the most ride time I can get , would a lower gear or larger motor help , what size batteries would I have to have and could they be bigger to  get more ride time ?  Where would I buy the sprocket I need for this bike ? I would like your recommendations on the wiring and electrical components for my project and pictures or model numbers I could look at , and cost estimate for the project .

We have twist throttles with built in battery meters and key switches so everything is on one unit. Ride time is determined by the speed the bike travels at and the size of the batteries.  Faster speed equals less ride time, and larger batteries equals more ride time. You can gear the bike to go 15 MPH but ride it at say 12 MPH to get more ride time if needed, or ride it at 8 MPH to get a lot more ride time, but still have the option to go 15 MPH when needed. The size of the batteries is the biggest factor into how much ride time the bike will have. You could use three 15 Ah batteries which would provide around 10 miles of ride time on flat ground without pedaling, or three 22 Ah batteries for around 12 miles, or three 35 Ah batteries for around 20 miles. Ride time will be significantly increased with light to normal pedaling.

The MOT-36600G motor has a sprocket that works with #41 and #420 chain. Wheel sprockets for these chain sizes can be purchased at go cart and mini bike parts stores.

Depending on the size of the batteries the typical cost including batteries and battery charger for a kit like this is between $450-$700. I can build a kit and get a definite total price for the parts if you would like. For the kit I would need to know what size batteries you would like to use?

Here are photos of some of the parts I recommend and links to the pages they are on.

MOT-36600G ( http://www.electricscooterparts.com/motors36volt.html )

THR-110K ( http://www.electricscooterparts.com/throttles36volt.html )

SPD-CT660B9 ( http://www.electricscooterparts.com/speedcontrollers36volt.html )

15 Ah, 22Ah, and 35 Ah batteries ( http://www.electricscooterparts.com/batteries.html )

Everything looks and sounds great , one more guestion , will I have to pedal the bike to get it started or will it take off by itself ?  I would like the 15 mph speed and the 20 mile range , so I will use the 35 Ah batteries. Build a kit with everything I need to put it together , including the batteries and give me a cost factor. Would there be any advantage or disadvantage in using the  Gel batteries ?  What is the brake switch wire's on the controller and is there any reverse option ?   The wheel or axle sprockets , how many teeth and diameter of the sprocket will I need ?

The bike will not need to be pedaled to be started - it will start on the electric motor's power alone and have good acceleration without pedaling. Gel batteries are an option but not a very good one in my opinion. Gel batteries will only provide around 80% of the ride time or mileage range that SLA batteries will for their size. So they will be heavier and bulkier. Gel batteries are also very sensitive to being overcharged and undercharged and due to that are not as reliable as SLA batteries. All electric scooter and bike companies that use lead batteries in their vehicles currently use SLA batteries.

The brake switch connector on the controller can be wired to a brake switch and will turn the motor off when the brake is applied, and then turn the motor on again when the brake is released. It is an optional connection and does not have to be used. We currently do not have any controllers rated over 500 Watts that have reverse. We do have 500 Watt controller with reverse though. If the bike used a 450 Watt gear motor then we would have a controller available for it with reverse.

I ran a gear ratio calculation with the MOT-36600G motor and assuming that the bike has 26" wheels the axle sprocket needs to have 25 teeth for a 15 MPH top speed. Here is an screenshot of the gear ratio calculation.

MOT-36600G has a 10 tooth sprocket which can be used with #41 or #420 chain so a #41 or #420 sprocket would be needed for the axle. We currently do not have axle sprockets for these chain sizes however I searched online and found many 25 tooth sprockets for #420 chain are available online.

I can definitely make a kit for your project. Before I make the kit I have a few questions I need to ask first.

  • Do you want to use the 600 Watt gear motor with a forward only controller, or the 450 Watt motor with a controller that has reverse?
  • Do you want to use GEL or SLA batteries?

Please let me know if you have any questions.

The 600 Watt gear motor with a forward only controller will be fine and the SLA batteries also . Can you give me the sight on line where I can buy the 25 tooth sprockets I need ? The sprocket that the foot pedal drives is a 22 tooth X 3 3/4 inch dia. with 5/8 inch axle keyed hole . Why use the brake switch is there any advantage in turning the motor on and off ?

One more question the battery charger , is it built into the controller or is it separate ?

I was able to find a 27 tooth sprocket for #420 chain with a 5/8" ID for keyed axle which is parts number 13407 at this link: http://www.gokartsupply.com/sprocket.htm

It has a brake drum built onto it which I do not think will get in the way of anything. I ran the gear ratio calculation again with a 27 tooth axle sprocket and it provides a 13.79 MPH top speed which is only around 1 MPH less than with a 25 tooth sprocket and the 27 tooth sprocket will provide more torque for off-road and uphill riding.

The only advantage to using the brake switch is that the throttle does not have to be releases when using the brakes. However since this feature does not exist on cars and motorcycles everyone is already trained to let up on the throttle when using the brakes so the power off on braking feature is not needed in my opinion. However if you want the bike to have a rear brake light then it would be needed.

The battery charger is not built into the controller. A separate battery charger needs to be used. For 35Ah batteries a battery charger with at least 4 Amps is needed in order to recharge the batteries overnight. I included a 4.5 Amp Soneil battery charger in the kit.

I made the kit for this project. Here is the link to it: https://cart.electricscooterparts.com/ProductDetails.asp?ProductCode=KIT-149

If you would like any changes made to the kit or if you have any questions please let me know.

Everything looks great , the price sounds good. I have a question about the sprocket you found with the 27 teeth 5/8 ID but also says 3/4 in axle , I'm uncertain about that one ?  I would like to have the 25 tooth sprocket if available , probably will have to experiment with both . I am looking for a sight that sells parts for the Schwinn Meridian Trike , but cannot find any that sells the parts , any ideas ?

I was not able to find a 25 tooth sprocket for a 5/8" axle at any of the mini bike and go kart parts stores that I looked at. I could only find a 23 tooth and 27 tooth. Here is the link to the 23 tooth: http://www.gopowersports.com/23-tooth-5-8-bore-420-x-sprocket-13406-no-refunds-or-returns-on-closeout-parts

For a 25 tooth sprocket I would check with all of the online stores that sell mini bike and go kart parts and ask them if they have one or can special order it.

I do not know of any websites that sell parts particularly for the Schwinn Meridian bicycle however Schwinn will sell you parts for it if they have them. Here is a link to their contact us page: http://www.schwinnbikes.com/usa/contacts

Please let me know if you have any questions.

I have ordered the 23 tooth sprocket and waiting to hear from Schwinn for part ordering information for my other drive wheel .  I am going to look at fat tires for the rims , as soon as I put this together I will get back to you and order the kit I need .  What do you estimate the shipping cost to be , zip code 70446 ?

I just checked and the best rate for shipping KIT-149 to zip code 70446 is with FedEx at $80.55. This kit weighs around 95 pounds due to the weight of the three large batteries. Please let me know if you have any further questions.

Login or Signup to post a comment