Power – Mass vs. Aero?

60pmh is the target top speed for Suilven EVA, a comfortable 60mph on a dual carriageway so as not to feel threatened by trucks tail-gating me in a minute sports car. This chart uses known formula to estimate the power required to achieve speed. The baseline chart suggests a very optimistic ~77mph.

Adding a gradient (1:20 as per the steepest section of the A4174 on my commute) drops that to a still optimistic 61mph.

Adding moderate acceleration (2ms-2) up that gradient, drops the top speed to 56mph. The results are dependent on multiple assumptions but the conclusion is clear; focus on reducing mass, the aero loads are secondary at these speeds.