Tires: Service and Repair
Fitting tyres for vehicles with and without tyre pressure monitoring systemNote!
^ Before fitting, it should be established whether a tyre pressure monitoring system is present! The tyre valve indicates whether this system is present. Without tyre pressure monitoring system - rubber valve; with tyre pressure monitoring system -aluminum valve. If a tyre pressure monitoring system is present, observe the special notes for the system.
^ The fitting machine described here is particularly suitable for large tyre combinations, such as those on the Cayenne.
^ The fitting machine must be modified for 20-inch tyres! Information on this subject can be found in the Workshop Equipment Manual.
^ All parts in contact with the wheel and the tyres are made of plastic.
^ No large point load for wheel and tyres.
Tools
Notes on removing/fitting tyres
Note!
^ When fitting tyres, the direction of rotation and the inner and outer sides should be noted.
^ Use only TIP TOP Universal, order No. 593 0601 (3.5 kg bucket) or Contifix as the lyre mounting paste.
^ Ensure that no damage (scoring, soiling) is caused to the assembly head of the fitting machine during fitting. Such damage may result in paint damage and pressure marks on the rim flange.
- Avoid slipping on to the rim flange. Use rim flange protection (assembly aid) -B-.
- Adhesive tape can be used to protect the rim flange in individual cases, in order to prevent any paint damage during fitting. The mounting lever can also be covered with adhesive tape in order to avoid damaging the area around the spokes during removal.
- The valve must always be replaced when changing a tyre.
- Check the wheel for damage.
Special notes for tyre pressure monitoring system
Note!
^ After fitting, if the previous wheels are still in the vicinity, (e.g. when changing winter wheels and/or wheels from another vehicle with a lyre pressure monitoring system), these can also sometimes be detected by the system. If one or more of these wheels has a minimum pressure of more than 0.4 bar below the required pressure, this can trigger a warning in the instrument cluster. If this happens, remove the wheels or adjust the vehicle outside of the radio range of these wheels using the Porsche System Tester.
^ In vehicles with a lyre pressure monitoring system, the valve and wheel electronics -A- are only replaced in exceptional cases. The following points can make replacement necessary.
The valve must be replaced if:
^ The wheel electronics are removed
^ The self-locking fastening screw is loose
^ The union nut is loose
^ The valve on the valve seat is leaking
^ The valve body is bent or broken
The wheel electronics must be replaced if:
^ The housing is visibly deformed
^ The filter surface is so soiled that it cannot be cleaned by wiping
^ Tyre sealant (tyre sealing liquid) has been used
1. Install wheel electronics loosely at the valve (do not tighten) and position in the valve bore together with the valve and bead seat sealing ring.
Caution! Remove assembly pin after installing valve. Otherwise the lyre will be damaged during fitting.
Tighten the valve only once to the stipulated torque in the rim.
2. Position the washer that has been chamfered on both sides and screw on the union nut as far as the mounting face. Visibly twist bore at valve foot. If necessary, block with suitable assembly pin. The tightening torque is 4 Nm (3 ft. lbs.) (± 0.5 Nm (0.5 ft. lbs.)).
3. Push wheel electronics -A- slightly into rim well (this adjusts the angle of inclination of valve to wheel electronics).
4. Carefully tighten self-locking (Torx) fastening screw T20 to a tightening torque of 4 Nm (3 ft. lbs.) (± 0.5 Nm (0.4 ft. lbs.)). The wheel electronics should now be lying evenly against the rim.
Removal
1. Clamp wheel.
2. When pushing off the tyre, ensure that the bead press-off tool is set to the exact inch graduation. If this is not the case, the rim flange may be damaged by the press-off rollers.
3. The wheel must be turned anti-clockwise when pressing the tyre off the rim. Otherwise, excessive forces occur on the fastening bolts of the machine which can lead to bolt breakage. The tyre beads can be pressed off at the same time or individually.
4. Before removing the tyre, coat the tyre beads with mounting paste to facilitate removal.
Note!
^ The mounting lever must be kept at a safe distance from the rim. This prevents damage (scratches, pressure marks) to the rim spokes.
^ In the case of vehicles with tyre pressure monitoring, the assembly head for the top tyre bead must be positioned approximately 15 cm behind the valve in order to prevent damage to the wheel electronics!
^ The assembly head must be positioned approximately 5 cm behind the valve for the lower tyre bead in vehicles with a tyre pressure monitoring system.
5. Put the assembly head on the rim flange. Position the assembly aid. The mounting lever is pushed into the deep bed underneath the first tyre bead, and then guided over the assembly shoe and pushed down.
6. Lift the tyre bead out of the rim bed by turning the wheel to the right.
7. Position the assembly aid approximately 5 - 10 cm right of the valve for the second tyre bead. Pull the tyre upwards and push it into the rim bed underneath the second tyre bead using the mounting lever. Make sure that the mounting lever is guided correctly. Turn the wheel to the right and remove the tyre.
Fitting
Caution! Injuries may occur as a result of high tyre seating pressure (a maximum of 4.0 bar must not be exceeded) caused by possible tyre or wheel damage (in a culmination of several negative factors).
^ The tyre must therefore be inflated in the tyre cage.
Tyre cage
Note!
^ Check the mounting head adjustment (must correspond with rim size).
^ The fitting machine must be modified for 20-inch tyres. Information on this subject can be found in the Workshop Equipment Manual.
^ The wheel electronics should not be treated with compressed air, mounting paste, cleaning agents or any other solvents.
^ Rims should not be cleaned with high pressure before tyres have been fitted.
^ Do not scratch filter surface of wheel electronics clear! Remove soiling with a lint-free cloth.
1. Free the wheel from the abraded rubber particles and check for damage.
2. A new valve insert must always be fitted.
3. Coat the wheel and tyre with tyre mounting paste -TIP TOP Universal, order No. 593 0601, or Contifix.
4. Place the tyre in the correct position on the wheel. Push in mounting arm and position on top of the rim flange. The assembly head must be offset by 180° to the valve.
5. Push the first tyre bead (lower tyre bead) partially over the rim flange. Adjust mounting head on rim flange and pull lower tyre bead onto rim.
Note!
^ During fitting, ensure that the tyre bead is not pressed against the wheel electronics.
6. Position the assembly head approximately 15 cm to the right of the valve and pull the second tyre bead (top tyre bead) onto the rim.
7. Remove entire wheel from lyre-fitting device. Without the valve insert, inflate tyre with air in the tyre cage until the tyre beads slide over the hump (to a maximum of 4.0 bar).
8. Screw in new valve insert and inflate tyre to the specified tyre pressure. Screw on valve cap.