Wheels and Tires: Description and Operation: Overview
Wheels and Tires
OVERVIEW
A number of alloy wheel designs are available ranging from 17 to 20 inch in diameter. A Tire Pressure Monitoring System (TPMS) is used to monitor the air pressure in each tire and inform the driver if the pressure falls below predetermined thresholds. For additional information, refer to Wheels and Tires Description
All wheels are of cast construction in aluminum alloy with the choice of wheel design dependant on the vehicle trim level:
- The 17 inch wheel, not available in North America, is available on Luxury vehicles.
- The two variants of the 18 inch wheel are offered on the High Luxury vehicle.
- The 19 inch wheel is an optional fit for both Luxury and High Luxury models; it will also be available with run-flat tires.
- The 20 inch wheel is available on Super Charged vehicles only.
A 4J X 18 inch temporary spare wheel is supplied as standard, although in some major European markets an Instant Mobility System is offered as an alternative to the spare wheel. The Instant Mobility System is capable of providing a temporary repair and tire inflation to a puncture of up to 6mm in diameter in the tread area of the tire. A puncture in the tire wall cannot be repaired using the system.
The vehicle jack and accessories are stored in the spare wheel-well in the luggage compartment.
Tire Changing
WARNING: Tires must be inflated to the recommended pressures when the tires are cold (ambient temperature) only. Refer to label on the 'B' pillar for recommended tire pressures. If the tires have been subjected to use or exposed to direct sunlight, move the vehicle into a shaded position and allow the tires to cool before checking or adjusting the pressures.
WARNING: Valve stem seal, washer nut, valve core and cap should be replaced at every tire change. Valve stem seal, washer and nut must be replaced if the valve retention nut is loosened. Sensor units and nuts must be fitted using correct torque figures and associated profile. Damage to the vehicle and consequently injury to the vehicle's occupants may result if these instructions are not adhered to.
Vehicles fitted with TPMS can be visually identified by an external metal locknut and valve of the tire pressure sensor on the road wheels. Vehicles without TPMS will have rubber tire valve.
When removing the tire, the bead breaker must not be used within 90 degrees of the tire valve in each direction on each side of the tire.
When using the tire removal machine, the fitting arm start position must be positioned as shown in the tire changing illustration for each side of the tire. The wheel can then be rotated through 180 degrees in a counter-clockwise direction. This will relieve tension from the tire bead allowing the remaining 180 degrees of the tire to be manually pulled from the rim.
When refitting the tire, position the fitting arm as shown. Rotate the tire and take care that the bead on the low tension side of the tire does not damage the sensor.
Run-Flat Tires
Run-flat tires can be handled, fitted and removed using the same principles as used for normal low profile and high-performance tires, with two exceptions:
- They are always fitted with tire pressure sensors.
- They have thicker bead cores and more rigid sidewalls which require special care when being mounted on the rims.
It is recommended that the tire fitting machine is fitted with plastic rollers for the upper and lower bead. This will ensure that the bead is removed gently, protecting the rims and the tire pressure sensors.
Adequate amounts of special fitting lubricant must be used to ensure that the sidewalls move with the minimum exertion and locate on the rim flange correctly.
Run-flat tires can be identified by the marking 'RSC' on the tire sidewall.
NOTE:
Vehicles fitted with run-flat tires are not supplied with a spare wheel, vehicle jack or wheel brace.
TREAD Act - NAS Only
Vehicles supplied to the North American markets must comply with the legislation of the Transport Recall Enhancement, Accountability and Documentation (TREAD) act. Part of the requirement of the TREAD act is for the vehicle to display a label which defines the recommended tire inflation pressure, load limits and maximum load of passengers and luggage weight the vehicle can safely carry. This label will be specific to each individual vehicle and will be installed on the production line. The label is positioned on the driver's side 'B' pillar on NAS vehicles and the inside rear face of the LH door on Canadian specification vehicles.
This label must not be removed from the vehicle. The label information will only define the specification of the vehicle as it came off the production line. It will not include dealer or owner fitted accessory wheels and tires of differing size from the original fitment.
If the label is damaged or removed for body repair, it must be replaced with a new label specific to that vehicle. A new label is requested from Jaguar parts and will be printed specifically for the supplied VIN of the vehicle.
Tire Pressure Monitoring System
The Tire Pressure Monitoring System (TPMS) is a driver assistance system which assists the driver to maintain the tire pressures at the optimum level. TPMS is standard fitment on NAS vehicles and an optional fitment in other markets. TPMS provides the following benefits:
- Maintain optimal fuel consumption.
- Maintain ride and handling characteristics.
- Reduce the risk of rapid tire deflation - which may be caused by under inflated tires.
- Comply with legislation requirements in relevant markets.
CAUTION: TPMS is not intended as a replacement for regular tire pressure and tire condition checks and should be considered as additional to good tire maintenance practices.
The TPMS measures the pressure in each of the vehicle's tires and issues warnings to the driver if any of the pressures deviate from defined tolerances. The space saver spare wheel is not monitored.
NOTE:
TPMS is not designed to warn the driver of a tire 'blow-out', as due to the short duration of a 'blow-out', it is not possible to give the driver sufficient warning that such an event is occurring. The design of the TPMS is to assist the driver in keeping the tires at the correct pressure, which will assist to reduce the likelihood of a tire 'blow-out' occurring.