The maintenance of appropriate tyre pressures is crucial to fuel economy, road holding, tyre life, accident prevention and a comfortable ride. Low tyre pressures can affect vehicle handing and greatly accelerate tyre wear and cause tyres to wear on the outside edges.
Tyres loose air pressure through a process called permeation where the air gradually migrates though the tyre causing a typical monthly loss of one or two psi, sometimes even more. Tyre pressures should be checked at least monthly, preferable when the tyre is cold. And please remember to check your spare tyres pressure; they are often forgotten about and frequently found to be flat. And if you have a space saver spare tyre, be sure to check the recommended air pressure which often will be 60 psi. And always replace the valve caps so that dirt and moisture is kept out of the valve stem. The complete rubber valve stem should always be replace when a new tyre is being fitted so the chances of gradual or sudden air pressure loss are minimised.
It is notoriously difficult to assess the air pressure of a modern radial tyre just by looking at it; always check your tyre pressures with an accurate pressure gauge. Given that pressure gauges at petrol stations are often grossly inaccurate due to abuse, poor maintenance and exposure to the elements, it is advisable to keep a good quality air gauge in your vehicle. These can be purchased from vehicle parts retailers at prices ranging from $10.00 to $30.00 approx.
Tyre pressures can have a big impact on our environment. Research suggests that most driver loose 10 to 50% of tyre tread life due to under inflation ultimately leading to increased quantities of waste being sent to landfills and scrap heaps. Also, low tyre pressures require extra fuel be burnt to push vehicles along on soft, underinflated tyres and increases the amount of energy used to make replacement tyres.
Best of all, a well maintained car with correct tyre pressures will save you quite big money.