Improper tire sizes

Tires are sized for a specific wheel. If the tires are not the correct size, the ABS may turn off. This problem deals primarily with the height of the tire and how it affects the wheel. A tire that cannot fit on a wheel would not be usable as the air could not be sealed in it.

Table of Contents

• 1. Symptoms
  • 1.1 ABS Light Comes On
  • 1.2 Variation in Speedometer

Symptoms

ABS Light Comes On

With improper tire sizes, the vehicle computer may detect abnormal driving conditions and switch off the ABS. This will cause the dashboard indicator to come on.

Variation in Speedometer

Tires that are too short will make the speedometer measurement greater than the actual speed. The diameter of the wheel will be reduced, and the revolutions of the wheel will be increased. When counting the revolutions, each mile in with normal sized tires would be, for example 0.9 miles.

Tires that are too tall will have the opposite effect. The speedometer reading will be less than the actual speed. For example the car may be travelling at 21mph, but the speedometer reads 20mph.