Those four round black pieces of rubber that your car is sitting on, you know, your tyres. When was the last time you checked your tyres? Are you aware of the importance of correct tyre pressures? If not then I hope by the end of this article you will, and if you are then hopefully you will learn something new aswell.
Over my sixteen years in the trade as a mechanic, 13 1/2 of which has been working in workshops attached to service stations, I have seen all kinds of issues relating to tyres and tyre pressures. During my time at the service station workshops, one of the services that we provided our fuel customers was complimentary tyre pressure checking when the customer asked for assistance. I would regularly come across under inflated tyres, over inflated tyres and even occasionally, tyres with the correct pressures in them. In fact I still see this every day during vehicle servicing.
So what tyre pressures should we be running in our tyres, you ask? Well it’s not quite as black and white as that, there is definitely some shades of grey mixed in there. Before we get into what pressures we need , lets first explore the importance of correct tyre pressures and what effect they have on not only the tyres but the car as well.
Whilst I don’t recommend it, over inflated tyre pressures can help to make your steering lighter due to less tyre rubber being in contact with the ground, therefore providing less resistance when turning the steering wheel from left to right, and vice versa. This little trick has been known to be used by dodgy used car salesmen, over the years, especially in the older days before our cars had power steering.
Better fuel economy is also a benefit that comes from over inflated tyres, again less rubber is in contact with the ground providing less resistance to roll, hence it takes less effort to get those tyres rolling and subsequently you use less fuel to do so.
The downsides to an over inflated tyre far outweighs the previous mentioned upsides. An over inflated tyre is more likely to suffer a puncture from a rock, spike, screw, nail, etc. that it runs over. An over inflated tyre is like a balloon blown up to its maximum. If you were to take a pin or the tip of a sharp knife and poke the balloon then it wouldn’t take too much effort to pop the balloon. A tyre is not too unlike a balloon in that the exact same thing can happen to the tyre. Repairing a punctured tyre just means that your car will spend more time off the road and in the garage and we don’t want that now, do we?
Excessive tyre wear is also a symptom of an over inflated tyre. With too much air in the tyre, the tyre begins to bulge and as the tyres rolls down the road, the road only contacts with the centre portion of the tyre wearing that section out much faster than any other part of the tyres tread. This means you end up back at the tyre dealer much sooner than you would like, to purchase some new tyres, counteracting the small savings you had made in fuel costs.
I personally do not see any upsides of an under inflated tyre, only issues that cause tyre damage and driveability concerns with your car. Now I can hear those who enjoy four wheel driving saying that reducing tyre pressures for various off road conditions is important, and I would agree with them. I do not, however, classify that as under inflation, because you are reducing those tyre pressures in order to serve a purpose for a specific circumstance.
Under inflation can cause numerous issues. A decrease in fuel economy is generally due to an increase in the tyres footprint. This means that there is a greater resistance to rolling therefore more fuel is required to make that tyre roll. Whilst on the issue of resistance, steering the vehicle can become heavier due to the fact that there is a larger tyre footprint in contact with the roads surface, requiring more force to turn the wheels from left to right.
The longer a tyre is driven with under inflated pressures the more heat those tyres generate. Tyres and heat do not agree and this can result in a tyre blow out. When the air inside of a tyre heats up, it rapidly increases tyre pressure and if not rectified can cause catastrophic tyre failure.
Low tyre pressures cause uneven tyre wear. As there is not enough air pressure in the tyre, the vehicle places all of its’ weight on both the inner and outer shoulders of the tyre. The tyres shoulders (or edges) are inline with the tyre side walls, the part of a tyre that is in contact with the tread and the rim. There is little to no air applying pressure on the centre of the tyres tread, the tyre is then forced to wear on the inner and outer edges of the tyres tread pattern, causing a premature end to the tyres life.
Having the correct tyre pressures will allow your tyres tread to wear nice and evenly, with all areas of the tread wearing at the same rate. Correct inflation pressures will produce the perfect balance between even tyre wear, the tyres life span, fuel economy and ride quality.
So what pressures should you have in your tyres? Well that all depends on a few different factors such as, What size tyres do you have? What size vehicle do you drive? How heavy is your vehicle? How much weight do you carry in your vehicle? Do you tow a trailer? And if so, Is it a small trailer or a large caravan? How much weight is on that trailer? Did all of that just confuse you? Well go through those questions again and work out a rough answer for each. Next open up your owner’s manual and look for the section on tyre pressures, then adjust your pressures to those that are stated in the manual. Alternatively call into your local mechanic or tyre dealership and ask for our opinion, after all, we are the experts.
Hopefully you now understand the importance of correct tyre pressures, what issues can and will, arise from the wrong tyre pressures and how you can determine what pressures your tyres require. Adjusting tyre pressures is a relatively simple task to under take, so there should be no reason why you cannot check and adjust them yourself.
Getting to know your car is the best way to improve your enjoyment in the driver’s seat. Use these tips, and more that you will find in other articles I have written here on my website and over on my Facebook page to help keep you and your car safe on the road. Safe Travelling.