buzzin hornet

[QUOTE=FormulaRedline,Feb 10 2011, 08:36 AM] The wheels have a much larger moment of inertia than those other components and do create a gyroscopic moment that resist a change in direction.

twohoos

FormulaRedline's talking about the *gyroscopic* effect, not just the rotational inertia.

Think of a holding a stick with a disk stuck on the end. Now swing the whole stick/disk assembly around you, and see how hard that is. Now *spin* the disk on the end of the stick and swing the whole thing again. It's a little bit harder this time: the added angular momentum of the spinning disk adds a little bit of "equivalent weight".

This is a separate effect from the pure rotational inertia we were discussing. In that case, in order to swing the stick/disk assembly (i.e. accelerate the car) at all, we have to simultaneously spin up the disk. Morevover, the faster we want to swing it, the faster we have to spin the disk. The same is true if we want to stop: we not only have to stop swinging, but we have to stop the disk spinning. By contrast, in the gyroscope experiment, we assume the disk is already spinning, and we don't have to speed it up or slow it down when we start or stop swinging.

I'd concur that the gyroscopic effect is very much second-order (or even 3rd-order), and therefore negligible.

GrandMasterKhan

100lbs = .1 in the 1/4 mile.

i had heard it was a 1:4 ratio for rotational mass, so 5.25lbs per wheel = a total of 25lbs which equals a total of 100lbs of dead weight.

this equation also relates with the handling of the car. Adding unsprung weight (wheels, brakes, control arms) will also be a 1:4 ratio.

So essetiall removing 25lbs from your wheels will make the car handle as if it is 100lbs lighter, because the suspension is able to move more quickly and is more responsive.

IntegraR0064

Nice, you have a five wheeled S2000!


Also as mentioned in the thread...it's a 1.4:1 ratio for rotational weight. Somebody changed the "point" to a "to" in the version you heard.