F1technical.net

munks wrote:

olefud wrote:Maybe a better term would be preload as a result of the centrifugal force –though I doubt that tire obey Hooke’s law and could well have a higher spring rate under centrifugal preload.

That occurred to me which is why I have continued asking ... whether there was a deeper down technical explanation or whether peanutaxis was using the simple but flawed explanation (see below). So yes, I agree that a tire is unlikely to obey Hooke's law, the rubber parts in particular. Now whether this counteracts the rounder shape I talked about (which would seem to be easier to compress), I'm not sure ... GSpeedR suggests that the overall effect is towards higher compliance, though.

I'll back-pedal a little bit, and say that tires can show a decrease in compliance (increase in stiffness) with speed. Temperature effects can go either way (softening of rubber/structure along with increasing internal pressure). The pressure effect can be controlled in practice but the temperature effect cannot. So I'll say that it depends (sorry), the tire experts here may be more comfortable stating one way or another. I will say that even centrifugal effects are not linear with speed (probably closer to v^2) and the effective tire spring rate is very likely to be nonlinear as well.

cheapracer wrote:

peanutaxis wrote:Si why don't F1 cars warble like road cars?

When they aren't going through the TV networks sound filters they do ...

http://www.youtube.com/watch?v=ZW2VSt_VfGM

Ah, right. (I can't say I noticed anything on that video, though.) And I guess once you add a gearbox, engine, drive shafts, wheels and ties they pretty much don't warble at all.

I have an E36 M3 and to be honest, I don't think it warbles at all. You feel it hit the wall when you get to the rev limit (so maybe it bounces slightly when you first get there), but after that it feels and sounds smooth.