Jaguar XK JJM 18 02 30 701 - Manual (Page 229)

263
Wheels and Tires
R
Treadwear number, 11
This number indicates the tire's wear rate.
The higher the treadwear number is, the
longer it should take for the tread to wear
down. For example, a tire graded 400
should last twice as long as a tire graded
200.
Traction letter, 12
This letter indicates a tire's ability to stop
on wet pavement. A higher graded tire
should allow you to stop your car on wet
roads in a shorter distance than a tire with
a lower grade. Traction is graded from
highest to lowest as AA, A, B, and C.
Maximum load rating, 13
This number indicates the maximum load
in kilograms and pounds that can be
carried by the tire.
Temperature letter, 14
This letter indicates a tire's resistance to
heat. The temperature grade is for a tire
that is inflated properly and not
overloaded. Excessive speed,
underinflation or excessive loading, either
separately or in combination, can cause
heat build-up and possible tire failure.
From highest to lowest, a tire's resistance
to heat is graded as A, B, or C.
Maximum permissible inflation
pressure, 15
This number is the greatest amount of air
pressure that should ever be put in the tire
under normal driving conditions.
Tire pressures during long term vehicle
storage
To minimise the possibility and effects of
flat spots during storage, the tires may be
inflated to the maximum pressure
indicated on the tire sidewall.
Note: Before using the stored vehicle on
the road again, ensure that correct tire
pressures are restored.
Wear
All tires fitted as original equipment
include Tread Wear Indicators (TWI) in
their tread pattern.
When the tread has worn to a remaining
depth of 1.6 mm the indicators appear at
the surface as bars which connect the
tread pattern across the full width of the
tire.
It is illegal, in certain countries, to
continue to use tires after the tread has
worn to less than 1.6 mm over three
quarters of the width and the entire
circumference of the tire.
It should be noted that the properties of
many tires alter progressively with wear.
In particular the wet grip and aquaplaning
resistance are gradually but substantially
reduced. Extra care and speed restriction
should therefore be exercised on wet
roads as the effective tread depth
diminishes.
JAG0393G