Tire pressure check
For the safe operation of the car, it is necessary to maintain a certain pressure in the tires. Remember that a tire with half the required pressure will at first glance appear to be inflated normally.
Visually check the tire pressure every day before driving. If by appearance it is noticeable that the pressure in one tire is lower than required, check the pressure in all tires with a pressure gauge and, if necessary, bring it to normal.
Note. When checking tire pressure, make sure you connect the pressure gauge to the tire valve correctly. If you connect the pressure gauge at an angle to the valve, you can bend the spool, which will bleed air through it.
To maintain optimum tire performance, check pressure only when the tires are cold. Under- or over-inflated tires can cause uneven tread wear.
Insufficient tire pressure is one of the most common causes of tire cracking, tread separation or «breakthroughs» with an unexpected loss of vehicle control and an increased risk of injury. Insufficient tire pressure increases sidewall deformation and rolling resistance, leading to heat build-up and internal tire damage. It can also cause additional stresses in the tire material, uneven wear, loss of vehicle control and accidents. Remember that a tire with half the required pressure will at first glance appear to be inflated normally.
Tread depth
In the grooves of the tire tread pattern there are «tire wear indicators» 1.6 mm high, located at right angles to the direction of translation of the tire. These indicators range from six to eight (depending on the manufacturer) placed at equal distances around the circumference of the tire. Tire sidewall markers (e.g. letters «TWI» or an icon in the form of a triangle) show the location of the tire wear indicators.
Tires can be used up to a profile depth of 1.6 mm, that is, the profile canadians must have a depth of at least 1.6 mm over the entire surface of the tire. However, for safety reasons, it is recommended to change tires at a profile depth of 2 mm.
Wheel runout
1. Raise the vehicle and secure it on stands.
2. Use a dial indicator to measure wheel runout (pic. 14.79).
Pic. 14.79. Using a Dial Gauge to Measure Wheel Runout
3. Replace the wheel if the wheel runout exceeds the limit.
Maximum allowable wheel runout:
- Radial runout of the steel rim of the wheel: no more than 1.2 mm
- Radial runout of the aluminum rim of the wheel: no more than 1.0 mm
- Axial runout of the steel disc of the wheel: no more than 1.2 mm
- Axial runout of the aluminum rim of the wheel: no more than 1.0 mm