Tyres give out their compressed air every day. During winters, it loses a couple of pounds every month; the summer count is a bit higher. However, the actual rate depends on individual car usage, in terms of distance covered and the routes hauled.

Ideal Pressure

The Pounds per Square Inch (PSI) measurement helps gauging tyre air pressure. Generally, mid-size and compact sedans must have PSI levels within the 30 and 40 PSI range. The upper limit stretches to 45 PSI for larger sedans.  

To ascertain the ideal PSI reading for your car tyres, read through the owner manual or refer to a yellow sticker usually pasted on the doorjamb to the driver's side or glove box door. However, these ratings won't apply if you've replaced the tyre during a recent car servicing session, different to the one originally installed by the manufacturer.    

The figures may vary for different tyres and as a general rule; it's recommended the reading isn't five PSI more than the readings on the tyre instruction manual.

Unless the owner's manual indicates otherwise, the rear wheels need a higher PSI count than the wheels at the front since the back end of the car bears more load (passengers plus luggage). Your car service technician may help out more with the assessment.  

Checking Tyres and Refilling

The tyres' air pressure must be checked first thing in the morning or when the rubber feels cold or is at air temperature. Assessing pressure when the tyres are hot, or immediately after a highway trip isn't recommended because air within heated-up tyres can expand due to hot temperature. Under such circumstances, wait for 30-40 minutes for the tyre to cool down.    

Never wait for the tyre pressure to hit its base levels; inflate the tyre whenever you possibly can. Ideally, a car tyre shouldn't be less than 3 PSI than its recommended levels. If so, you end up burning an additional percentage of fuel. If the PSI levels go down even further, the fuel depletion counts tanks in correlation; not to mention the wear and tear incurred.

Also check spare tyre pressure. You don't want the spare rubber to disappoint during a wheel puncture or any other emergency scenario.  

Under-/Over-Inflation Impact

When your car tyre isn't filled with adequate air volume, increased wear and tear issues on the tyre sides may arise. Similarly, over-inflated rubber is also not ideal for driving and can cause a sudden blowout or tyre explosion.

When the tyres are air-filled more than their capacity, the tyre elevates and a lesser portion of the rubber touches ground. This hurts the vehicle's stability as it bounces or responds vigorously to even minor road indentations.

On the other hand, an underinflated tyre has more tyre rubber in contact with the ground, which augments road-tyre friction. This constant abrasion can cause overheating of tyres or tread separation. To ensure you don't encounter low tyre air issues, look out for squealing sounds when cornering.

For more information, contact a company such as 1st Choice Mechanical Repairs.