The cause of the “saw-tooth tread wear” lies in the cooperation between the tread and the road surface.

Where can we see the saw-tooth tyre wear most often?

The tyres on the rear (dead) axle are more susceptible to the saw-tooth tyre wear.

Why is this happening?

Imagine how the tyre on the rear axle operates. The vehicle is driven by the front axle, while the rear axle is dragged along. When driving, the road surface force always has the same direction, i.e. it is always stronger toward the trailing edge of the tread blocks, which causes them to wear. When braking, the rear tyres push on the road surface, causing a stronger mutual reaction, which still works in the same direction, thus wearing the same edges even more.

Which factors influence the saw-tooth tyre wear?

  • Tread pattern - The greater spacing is between tread blocks, the more the risk of the saw-tooth wear occurring increases
  • Mixture hardness – hard tyres will be less susceptible to saw-tooth wear and noise
  • Tyre pressure - overpressure increases the risk of saw-tooth wear
  • The condition of suspension and shock absorbers - damaged suspensions and worn-out shock absorbers also increase the risk of saw-tooth wear
  • Driving style – abrupt acceleration and braking will increase the saw-tooth wear on dead axles. Fast driving on winding roads will diminish the effect.
saw-tooth-1-1

Where does the saw-tooth wear occur?

Does a multi-link suspension cause saw-tooth tyre wear?

Contrary to popular belief, no. In the case of such a suspension, the phenomenon is much more visible, as the tyre is not worn out laterally to the driving direction, which is the case with older suspension systems, where the saw-tooth wear was lateral.

How do I minimize the effect?

In order to minimize the saw-tooth tyre wear of the tyre tread, one should systematically (at least once every season or every 8-10 thousand km) switch the positions of the vehicle’s wheels/tyres.

The chart below shows the recommended switching direction for two-wheel drive vehicles with both symmetrical and asymmetrical tyres.

saw-tooth-2-1

Saw-tooth tyre wear

Directional tyres may be rotated according to the chart above, but they have to be removed from the rims to retain the correct rolling direction.

For vehicles equipped with directional tyres, the following switching scheme is recommended, as it does not require the tyres to be removed:

saw-tooth-3

Saw-tooth tyre wear

Switching in four-wheel drive vehicles should be performed according to the following chart:

4WD

Saw-tooth tyre wear

 

Such switching should ensure that the rolling directions of symmetrical and symmetrical tyres is switched. In this event, directional tyres should be removed from the rims to retain their correct rolling direction.

For 4x4 vehicles with different tyre sizes on front and rear axles, the following switching scheme is recommended:

saw-tooth-5

Saw-tooth tyre wear

The chart above applies to both symmetrical and asymmetrical tyres. The switching should ensure that the rolling direction is reversed.
In case of severe saw-tooth tyre wear, the tyres can be evened out using a special device available in some tyre service centres, which may diminish their durability. It should, however, be noted, that this kind of uneven wear does not directly influence the driving safety, it just decreases comfort by increasing noise levels.