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More National Speedway Tires Are in Use
in Philadelphia Than Any Other Make
of Equal Factory Output
The new process of molding and curing by internal hydraulic pressure evolved by
the makers of National Speedway Tires totally eliminates structural weaknesses
They are sold to you at the lowest first and last cost.
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THIS great discovery reduces the three vital
causes of tire trouble stone bruises, rim cuts
and blowouts to the vanishing point.
The ordinary, old-style method of tire curing
calls for hundreds of tons of pressure applied
externally by a rigid, vise-like mold that often
pinches the fabric and bruises the soft, uncured
carcass. These wounds are invisible to the eye.
But the defects are there no manufacturer can
totally eliminate them and the wear and tear of
the Troad does the rest.
It remained for the makers of the National
Speedway Tire to perfect the logical process of
applying hydraulic pressure internally.
Instead of using a solid iron core, the
National Speedway Tire is built up
on a collapsible core one that can
be taken apart and removed
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without npQtrovinp thp shane m-!.
of the uncured tire after as
emb ling.
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THE mold is of heavy two-piece construction,
like other molds, but made large enough to
accommodate the uncured tire .and close com
pletely around it without any pressure. This is
because the actual curing pressure is applied
internally when the mold is placed in the vulcan
izing kettle.
This is a wholly unique process evolved by the
makers of National Speedway Tires. A specially
constructed inner tube of the exact dimension
and shape of the inside of finished casing is placed
in the tire, and then subjected to a hydraulic pres
sure of 200 pounds to the square inch. This pressure is
maintained during the whole period of curing.
Distortion and pinching are impossible.
A finished National Speedway Tire is
flawless absolutely certain to deliver its
full 6000 miles of guaranteed service
and a big margin beyond.
Since the discovery of this new
method, National Speedway adjust-
menis nave averaged noi more
man one in every zuuu ures soia.
The amazing success of our curing process, eliminating "seconds" and practically doing away with adjustments,
has so reduced the cost of manufacture that National Speedway Tires are priced lower than others of a like
rating. And the cost to you per mile is reduced far more.
Remember that National Speedway Tires are made in our great factory at Pottstown, close toPhiladelphia,
insuring prompt deliveries. Telephone, write or wire if your local dealer cannot supply you and our Broad Street
salesrooms will give you prompt attention and the best of service. Free Delivery Anywhere.
National Rubber Products Corporation
660-662 North Broad Street, Philadelphia
Bell Phone Poplar 3197-3198-3199
Keystone Phone Race 4-118
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