1. T RIBOLOGICAL S YSTEM OF T IRE W EAR Y IN -Y U C HEN MANE6960 – F RICTION W EAR AND L UBRICATION OF M ATERIALS P ROFESSOR E RNESTO G UTIERREZ -M IRAVETE M AY 13, 2015

2. Introduction Tire: A protective cover to contain compressed air in a toroidal chamber that is attached to a steel rim or wheel of an automobile – The tire must transmit forces from the car to the road during driving – The tire must provide a firm grip on the road May be dry or wet Sometimes contaminated — intentionally (salt during winter) or accidentally (spillage) – The tire is also used to absorb unevenness of the road and provide a comfortable journey – Tire has to do this at a low cost and must have a sufficiently long life with ample safety provisions against accidental deflation

3. Wear Characteristics Tread loss – The averaged value of the depth loss of tread through wear. It is measured for all the grooves and expressed in millimeters Rate of wear – Loss of tread (i.e. millimeters per 10,000 km of travel) Tread wear index – The ratio of wear rate of a control or reference tire to that of the experimental tire, expressed in percent

4. Tire Wear System Archard Wear Theory V is the total volume of wear amount K is the wear coefficient F N is the normal load of the contact pair H is the hardness of the tire L is the slip distance P is the normal pressure of contact surface A is the contact area

5. Tire Wear System Archard Wear Theory is the slip ratio t is the time is the ratio of volume wear