Key Electric Assist Technologies For Converting A Tadpole Trike Into A Pedal Assist/E-Assist System - Part 4

Which eBike system is best for Tadpole Trikes?

Having understood some of the technologies, now let us look at the tadpole trike geometry. This is a good place to start: http://www.jetrike.com/tadpole-or-delta.html. Other good references are “The Recumbent Trike Design Primer” and this thread.

Understanding Dynamic Behavior and Trike Stability

In the article at jetrike.com, the author talks about the dynamic behavior of a tadpole trike. The author states:

“The tadpole rider's CoG is lower, but located ahead of the forward tipping axis so it would tip forward under a 1g braking force. With modern caliper brakes, this would have a tendency to lift the rear wheel. On a downward slope the tipping threshold would be even less, exacerbating the problem.”

Intuitively, one can conclude that having a direct drive motor actually improves the stability of a tadpole trike. The mid-drive motor will add significant weight to the front boom exacerbating the stability issue. The figures below illustrate this in a better fashion.

Figure 4 - Center of Gravity for a Tadpole Trike without any eBike System

Figure 5 - Movement of Center of Gravity indicates that the a mid-drive system will be less stable than a direct drive system