Checking tire pressure. Mercedes-Benz E-Class

REPAIR MAINTENANCE OPERATION OF MOTOR VEHICLES
Mercedes-Benz E-Class

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The pressure should always be checked on cold tires: while driving the tires warm up and the pressure increases. If you measure the pressure immediately after the trip, the result will be distorted.

The following are recommendations for checking tire pressure.

1. Carry out the checks tire pressure regularly every 3-4 weeks.

2. The pressure drop of about 1.5% per month is the norm for brand tires. If this value is greater, check the tire in the workshop.

3. Gates swap should always close the cap, since the dirt from entering the valve may clog the valve, and it will not be hermetically sealed.

Fig. 7.27. In the Mercedes E-class values prescribed tire pressure listed on the sticker on the back of the fuel tank flap

Fig. 7.28. Tire wear after a long operation at low inflation pressure

4. Tyre pressure must not fall below the values indicated in the table on the back side of the petrol tank hatch (Fig. 7.27), since this leads to increased tire wear characteristic (Fig. 7.28).

Fig. 7.29. Tire wear as a result of long operation with pressurized air in it or frequent trips to the maximum speed

5. The pressure of 0.2-0.3 bar above normal has some advantages: the steering is more sensitive, tires wear out more slowly (Fig. 7.29), and even a little lower fuel consumption. Disadvantage: reduced damping properties of the tire.

Fig. 7.30. Spot the tire contact with the road: A - at normal pressure, the whole working surface of the tire contact with the road surface; B - pressurized tire contact with the road only the middle portion of its working surface; C - low-pressure contact patch falls on the edge of the tire

Fig. 7.31. The scheme of shift of wheels

Technical Dictionary

Tire pressure

Tyre pressure determines the shape and size of the tire contact with the road surface (Fig. 7.30), and thus its service life, as well as fuel economy and driving performance (in low pressure tires react inaccurate and late movement on the wheel).

PRACTICAL ADVICE

Proper transposition of wheels

1. If you have a new trunk spare tire, you can save. The important thing to have in selling tires with the same tread pattern from the same manufacturer. Then you can buy another bus, and "footwear" for one axis is provided.

2. The purchase of the new tires can be delayed if the swap wheels as follows: front and rear on one board (not diagonally!) And in compliance with the same direction of rotation (Fig. 7.31). In this case there is a more uniform wear.

3. The disadvantage of this method lies in the fact that when worn come directly replace all four tires. In addition, due to the reshuffle at regular intervals run harder to recognize the nature of the possible violations of deterioration in the suspension, steering and shock absorbers.

4. When replacing, always make sure that in any case on the same axle tires were installed the same manufacturer, with the same profile and service life.

5. Another embodiment considers permutation that tires of the front wheels will wear. When they reach the minimum level of tread height of 1.6 mm, front tires can be interchanged with the rear wheels (keeping the parties) if they are, of course, has not worn to the limit. Thus, you need only two new tires for the rear axle.

6. The basic principle is that that the rear axle must be installed with a smaller tire tread wear, since it has a profound effect on the stability of the vehicle. If damaged, the front tire on the road the car still retains control, while damage to the rear wheel almost inevitably lead to a skid.