This seems to confirm that radial belted tires are indeed weaker by themselves as the belts are not directly attached to the bead.g-force_addict wrote: IMO they shouldn't use conventional belted tires at all no matter if they are radial or bias ply.
Just Googleing belted tires you get plenty of attorneys offering litigation for tread separation. And this on road tires at low speeds.
So unless the belts aren't strongly secured to the tire bead by overlapping cords or something they are a no go.
High speed tires usually use cap plies that are supposed to prevent belt separation.
http://s.hswstatic.com/gif/tire-cutaway-big.jpg
AFAIK cap plies don't run all the way to the tire bead
http://dasselaw.com/images/NOC_F6.jpg
So only the adhesive power prevents the belts from separating at speed.
Steel binds poorly to rubber so steel belts are reportedly more prone to separating at high speeds than those made of Nylon, Kevlar or some other textile materials.
Carroll Smith wrote in Tune to Win (1978):
http://books.google.com.gt/books/about/ ... edir_esc=y
'If the cords are arranged radially the tire will have the softest ride possible with maximum self dampening but will have no lateral stability.
This is why radial tires require circumferential belts, preferably of steel.
Racing tires at the time of writing, cannot accept the weight or the rigidity of the belts.
On the other hand, if the cords were arranged circumferentially the tire would have excellent lateral stability, a very harsh ride and it would be impossible to hold the profile shape.
So, borrowing a page from the tailors' and sailmakers' books. the cords of the racing tire are arranged on the bias, thus providing strength in three planes simultaneously.
Racing tire cord angles are closer to the circumferential than passenger bias tires in order to provide smaller slip angles for a given cornering force and a more efficient tire -as well as to provide more support for the wide profile.'
So this explains why true radials are seldom used in (hardcore) racing.
Even Formula 1 tires are actually bias-ply. Although the cord angle is smaller than those tires actually called bias ply.