<VV> Re:Mo' Wheelz

[Padgett]

>  The late '60s reverse-moulded,
>bias-ply, "cantilever" race tires (I hadn't seen that name association
>before seeing it on this forum, but it is apt) such as the Goodyear
>Bluestreak 4.75/8.50-13 tires I still have (as mementoes) have 7-inches
>of tread and were certainly designed for wheel widths smaller than
>either the tread or section widths.  Section height to section width
>ratio is around 50%.  So I guess today they would be 250/50-13s.

Called them "cantilever" waaay back then. First mention that I know of in 
print was the 1965 Car and Driver "2+2 vs 2+2" road test.

However they were a "kludge on a kludge". Back then the SCCA had very 
restrictive rules on wheel width in stock classes of roughly 1.5" more than 
stock. This mean that my B/P Corvette with 10.45x15s on the front and 
12.65x15s on the back was limited to a 7.5" wide wheel (actually for 
everything but the Nationals, most ran the stock 15x8 later Corvette wheel 
you could buy for $15 a pop in Detroit). Goodyear and Firestone both 
realized this was an issue and so the cantilever racing tire was developed 
to compensate and provide a tire with a large contact patch that could be 
used on a too-narrow rim.

Those tires were better than the alternative but moved A Lot under the car 
and took their own special driving style (the also had very soft/thin 
sidewalls and the pressure often needed topping up daily - left for a week 
it would be flat. This was not a passenger car tire.

By 1966-67 the passenger car version was intoduced first as the Firestone 
"Wide Oval" as the first '70 series tires were called. You were doing good 
if a set which cost about $100 1967 dollars lasted 8,000 miles. Keep in 
mind that at this point a 6" rim was considered wide.

Today things are different, tire technology in particular is light years 
ahead of what we had then and "going up in smoke" on the street is a rare 
occurance. However, given the best of all possibilities, if you are going 
to race, it is best to have a rim at least as wide as the section with of 
the tire and when you consider distortion under lateral stress (cornering) 
it is easy to see why.

Padgett