That "Forgiving nature" is a result of bias ply construction. The bias ply
tires tend to have a more convex shape to the contact patch than do radials.
Bias ply's will sort of roll a bit towards their sidewall before losing grip
thus giving you a lot of warning before they break away. Radials are
flatter and don't roll onto the sidewall as much (under normal
circumstances) thus when the lose grip, they tend to do it all of a sudden.
That's an oversimplification but you get the idea. I remember back in the
mid Eighties that one guy driving a Porsche 956 al Le Mans reported during
qualifying that the car would dart about very suddenly going down the 220mph
Mulsane straight. They traced the problem to the tires and to correct it
increase the front tire pressure a couple of psi, which created more of a
convex shape to the contact patch.
Just a bit more of the useless trivia I've picked up over the years.
Brian
-----Original Message-----
Shortly after buying my roadster in 1968 I changed to a set of Pirelli rayon
radials. They were not tubeless, you had to use a tube. I ran these tires
with no problems untill they rotted with age. They were very forgiving. The
Michilins of that era had a reputation of breaking loose with very little
chance of recovery.
Gary Russell
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