Rethinking the 4 PSI Tire Rule: A Quick Check With Real-World Limits
The article explains that tires should be inflated to the manufacturer’s cold pressure (not the sidewall max); after about 30 minutes of highway driving, a rise of roughly 4 PSI is normal due to heat from hysteresis. A larger rise suggests underinflation, a smaller rise overinflation, but the rule isn’t universal: it assumes steady highway speeds on paved roads and doesn’t apply to off-road conditions or unusual tires (e.g., drag slicks, mud/TAs). Tire type, temperature, and TPMS readings can affect results; sources like Tire Rack, Priority Tire, and AAA offer similar guidance. If tires are warm, inflate roughly 4 PSI past the cold spec. Use the rule as a handy quick check, not a replacement for the manufacturer’s recommendation.
