Can tire pressure increase without physical of air insertion?
Driving from Flagstaff to Tucson, barametric pressure decreases, altitude decreases, heat greatly increases. 20 miles from Tucson tire blows the tread – still holding pressure, went to tire guy, did pressure test – shot the gauge out of his hand (about 75 psi on both fron tires) any ideas on what happened – Tire guy said the only way to increase pressure was to physically aid air.
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Air can expand and contract with heat/cold… but I doubt the pressure difference would be more than +/- 5 lbs. It is most likely the tires were over inflated to begin with. Most passenger cars only require 30-35 lbs of tire pressure. No road circumstance would cause the air pressure to double.
What's my guess? Go back to the tire gauge used when the tires were FIRST inflated… I'll bet its defective, or it was used improperly. Either that, or no tire gauge was used at all, and the tires were inflated by eye… heaven forbid.
It should also be noted that many people read the max inflation notice on the sides of their tires, and promptly fill them all the way up… 40-50 lbs. Your CAR, however, may have different requirements. The auto manufacturer has the appropriate air pressure for your tires listed on a placard inside the driver side door jamb, the glove box, or the user manual. As stated before, usually no more than 29-35 lbs.