The ‘Crown’ eTrike PowerTrian

A few words about the powertrain that will be used on the trike.

As previously mentioned, it will consist of Matt Shumaker’s single stage Edrive kit with a 4kW (5kW Peak) astroflight Astro 3210 Brushless Motor. This electric motor, when used at 48V, will have a maximum speed in the area of 10,000RPM under load.

I have been told that using the standard pulley on the single stage edrive will give a reduction of 4.375 to 1.  So this will drop the RPM down to around 2300 on the output sprocket.

Provided the motor had the power to reach this RPM on the back wheel (which it wouldn’t by any stretch of the imagination) this would equate to 176km/h. So obviously this needs to be reduced further.

In order to reduce this RPM down to a more manageable speed at the rear wheel this needs to be reduced further by 3 to 1. The output of the edrive is a freewheeling 16tooth sprocket. So a 48 tooth sprocket mounted to the back wheel with a disc brake adapter is required to give an over all reduction of 13.125.


The sprocket and adapter is yet another fantastic bit of work from Matt Shumaker. More information can be found about the adapter here.

In short, this should allow for a top speed of 58km/h. This should make for an… interesting ride to say the least

Many thanks to Grinhill for his help on this topic.

About Richard

I am a Materials Engineering working in the field of Magnetic Materials in Melbourne, Australia. This blog covers my personal interest in all things CNC.
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