diagonal tyre. Because the radial tyre makes the patch constant, until it
collapses very quickly. The slipangle/grip curve will rise fast with
increasing angle, and then flatten somewhat at the peak, and then drop very
quickly (or in other words, very difficult to recover once overstepped). I
think that the peak slip angle for a racing radial tyre is 7 or 8 degrees,
probably 12-15 degrees on a road tyre made for longevity.
A diagonal tyre, however, has a contact patch that degrades more slowly,
decreasing in size with greater angles, and yielding less grip. So, a radial
tyre has a much flatter slipangle/grip curve. Especially on the "far" side.
Making it easier to recover. But with less grip.
But when that is said, the tires in GPL just give too much grip on the far
side of the slipangle/grip curve, and this enables us to drive with the rear
sticking out 30 degrees lap after lap. They didn't drive that way back in 67.
Well, they did, if they made a mistake. We focus on the footage, but we see
only the close shave cuts, I think.
My main complaint about GPL is that there is no way telling if a tyre is
sliding or gripping. This is fundamental in all road racing, and should have
been treated more thoroughly by Papy.
---Asgeir---
> In fact, after reading this very informative article,
> http://www.racesimcentral.net/
> I am even more convinced that this is so. The sidewalls in a bias ply
> tyre (which is what mainly affects the behaviour at low slip angles) are
> probably even harder than in a comparable radial tyre, which means that
> the cornering stiffnesses of both the radial and the bias ply tyre could
> be comparable.
> The radial tyre, on the other hand, since its sidewalls may be soft but
> the contact patch is very rigid, will probably have linear
> chracteristics in a far longer range of slip angles (should the
> deformation of sidewalls remain at least somewhat linear), and would
> also let go much more suddenly for the same reason.
> Could anyone with more knowledge shed some more light on the subject
> (Doug, are you around :) ) ?
> -Gregor