Tire PSI Formula:
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Definition: This calculator determines the optimal tire pressure based on vehicle load, tire contact area, and a safety factor.
Purpose: It helps vehicle owners and mechanics maintain proper tire pressure for safety, performance, and tire longevity.
The calculator uses the formula:
Where:
Explanation: The load is divided by the product of tire contact area and safety factor to determine optimal pressure.
Details: Correct tire pressure ensures even wear, better fuel efficiency, proper handling, and prevents blowouts.
Tips: Enter the load per tire in pounds, tire contact area in square inches, and safety factor (default 1.2). All values must be > 0.
Q1: How do I find the tire contact area?
A: Measure the length and width of the tire's contact patch when loaded, then multiply them.
Q2: What's a typical safety factor?
A: Most passenger vehicles use 1.2, but this may vary for heavy loads or performance vehicles.
Q3: Should I use this instead of manufacturer's recommendation?
A: This provides theoretical optimal pressure. Always consider manufacturer recommendations as primary guidance.
Q4: How does temperature affect the calculation?
A: Tire pressure changes with temperature (1 psi per 10°F). For accuracy, measure when tires are cold.
Q5: What if my calculated PSI differs from the door jamb sticker?
A: The sticker shows manufacturer recommendations based on typical use. Consult a professional if unsure.