1. Tire Pressure Lab

2. Goal of the Lab Determine the average tire pressure for a passenger vehicle. Measure the contact patch of the tire. Calculate the aspect ratio of the tire. Use data from lab to determine weight of the car.

3. Tire Pressure Tire pressure measures the amount of air in your tire per unit volume. Units: lb/in 2 Method: Place gauge on uncovered valve stem and release air from tire into gauge. Read the gauge.

4. Tire Pressure Gauges

5. Contact Patch Def: The area of the tire that comes in contact with the pavement.

6. Contact Patch cont…. Method: Use a ruler to measure the area of the tire that is touching the ground. Side Back Side x Back = Area

7. Contact Patch cont…. Units: in 2 Under or over inflated tires may result in an incorrect contact patch area!!

8. Aspect Ratio Def: A comparison of the tire height to width Formula:

9. Aspect Ratio cont…. Low number= Low Profile Tire Greater width than height

10. Weight of the Car Weight is calculated from the contact patch and the tire pressure. Formula: (Contact Patch in 2 x 4 ) x (tire pressure lb/in 2 )

11. Tire Serial Numbers P 185 80 R 14 Type of tire Width in mm Aspect Ratio Rim Size in inches

12. Tire Serial Numbers cont…

13. Data Table Name and type of vehicle Contact Patch (in2) Tire Pressure (psi) Weight (lb) Height (cm) Width (cm) Rim Size (in)