Triumph TR2 - Factors Affecting Tyre Life and Performance

WHEELS AND TYRES
a tube patch attached to the inside of
the casing.
This
will protect the tube
from possible chafing at that point.
If nail holes are not clean, and par-
ticularly if frayed or fractured cords
are visible inside the tyre, expert
advice should be sought.
I. FACTORS AFFECTING TYRE LIFE
AND PERFORMANCE
(a) Inflation Pressures
Other things being equal there is an
average loss of
13% tread mileage for
every
10% reduction in inflatiox pres-
sure below the recommended figae.
The tyre is designed so that there is
minimum pattern shuffle on the road
surface and a suitable distribution of
load over the tyre's contact area when
deflection is correct.
Moderate under-inflation causes an
increased rate of tread wear although
the tyre's appearance may remain
normal. Severe and persistent
under-
Fig.
Excessive Tyre Wear due to persistent
under-idation.
inflation produces unmistakable evi-
dence on the tread (Fig.
2). It also
causes structural failure due to ex-
cessive friction and temperature
within
the casing (Figs. 3 and 4).
Pressures which are higher than those
recommended for the car reduce com-
fort. They may also reduce tread
life
due to a concentration of the load and
Fig. 3 Breaking up of Casing due to over-
flexing and heat generation.
Fig.
q
(b)
Running deflated destroyed this Tyre.
wear on a smaller area of tread,
aggravated by increased wheel bounce
on uneven road surfaces. Excessive
pressures overstrain the casing cords,
in addition to causing rapid wear, and
the tyres are more susceptible to
impact fractures and cuts.
Effect of Temperature
Air expands with heating and tyre
pressures increase as the tyres warm
up. Pressures increase more in hot
weather than in cold weather and as the
result of high speed.
These
factors