Chris's new build of an MX5 based car

[CTWV50]

OK I've had a bit more of a play with these calculators and as one of them gives me a "motion ratio" of 0.411. see below..

MOTION RATIO
Motion Ratio = (Dimension A / Dimension B) * sin(Spring Angle)

The motion ratio is the mechanical advantage (lever ratio) that the wheel has over the spring in compressing it.

I converted this for the Staniforth calculator to 2.43:1 and then my cpm dropped to 100.74cpm.

I wasn't sure if this was correct but looking at the wheel rate the numbers are very similar. but one is described as "effective wheel rate" so I'm not sure what the difference is there.

WHEEL RATE

Effective Wheel Rate = Spring Rate * (Motion Ratio)2

Wheel Rate is the effective spring rate at the wheel, due to the leverage advantage the wheel has with respect to the spring on the control arm.


Staniforth gives a wheel rate of 76.25lb/in whereas hypercoils gives an effective wheel rate of 72.55lb/in.



Does that look about right? I have no idea!