Even a brand new tire with no leaks will change pressure with Temperature change.

A rough calculation is 2 psi for every 10 Deg C change (up or down).

Under inflations will result in

–Reduced Fuel Economy

–Increased tire swear

–Increased heat in tire side walls from flexing that can cause blow out.

Over Inflation will result in

— Increased Tire Wear

— Rough Ride & increased wear on steering and suspension components

— Possible handling problems on wet or slippery roads

Checking tire pressures before a trip and when seasonal temperature changes occur will increase the safety, reliability and decrease operating costs of your vehicle.