Keeping your car tyres at their ideal pressure gives you improved mileage, and helps prevent tyre treadwear—saving you money on premature tyre replacement. Even more importantly, it improves your car’s ability to break and round corners safely, which is vital from a safety perspective.
Adjusting car tyre pressure is easy enough, but it can be confusing trying to understand what your tyre pressure should be. In this article we’ll run through the basics of tyre pressure, talk about why having appropriate tyre pressure matters, and about how you can adjust it.
Why does having the right tyre pressure matter?
If your tyres are underinflated (have low pressure), the sidewalls of your tyre can be stressed when driving on bitumen. Tyres may crack or bulge, and lose their ability to perform as per their design, which could be hazardous. Very under-inflated tyres could also affect your vehicle’s ability to brake in time, which again, is hazardous.
Over-inflated tyres (high pressure) have a smaller area of tyre touching the road, meaning risk of increased wear in the centre of your tyre and less grip on the road. This may make for a bumpier ride, higher risk of skidding, and a higher likelihood of a tyre blowout or puncture. Any of these occurrences could be hazardous when you’re driving, plus could cost you money in premature tyre replacement.
Knowing the right tyre pressure for your vehicle
To find out the appropriate pressure for your front and rear tyres, you can check:
- Your vehicle’s owner manual
- The tyre placard sticker on the inside of your driver-side door
- The fuel filler flap.
There should be a recommendation for both normal and high-speed/high load usage, so adjust pressure according to how you are using your vehicle.
Important: There is a tyre PSI listed on the tyre itself. Don’t go by this pressure, as this refers refers to the maximum pressure the tyre can be inflated to—not the recommended pressure for your particular vehicle.
In general, passenger vehicles have a recommended PSI ranging between 32 and 35, with many recommending 32-34 PSI for front tyres and and 30-32 PSI for rear tyres. Go by the recommended tyre pressure for your vehicle, before the general recommendation if you can. (For more on PSI, see What PSI should my car tyres be?)
Lastly, if you’re having trouble finding the right pressure for your vehicle, Jim’s mobile tyre shop can recommend the best pressure for your vehicle and usage. We can also complete a tyre pressure check for you and/or tyre repair for you.
Other conditions that affect tyre pressure
Recommended tyre pressures are based on cold inflation pressure, (the pressure your tyres should be when cold). Tyres expand in the heat, whether this be ambient heat, sun on your tyres, or heat caused by friction between your tyres and the road. Whichever the heatsource, once your tyre heats up, the air pressure within it expands and the tyre pressure changes.
Hence, it’s important to check tyres when they’re cold. This means doing your tyre checks first thing in the morning when your vehicle has barely been driven. Even better, get Jim’s mobile tyre shop to come to you and complete a tyre pressure test before your vehicle has warmed up at all.
Remember, your tyre pressure fluctuates throughout the year as temperatures change. This is why it’s recommended you check tyre pressure at least monthly, so that you can be sure you’re not losing too much pressure. And if you’re headed somewhere extra hot or cold, adjust tyre pressure accordingly.
How and where you drive can impact tyre pressure. For example, if you carry heavy loads or trailers, or drive at sustained high speeds, you need to factor those actions in and increase your tyre pressure to account for the extra pressure placed on your tyres. Again, the vehicle tyre placard in your door jamb will list recommended pressure for high-speed/high load usage.
Conversely, if you’re driving off-road, the last thing you want is over-inflated tyres, as they are more likely to puncture. So for off-road driving on dirt, mud, sand you may need to slightly under-inflate tyres, so they have extra give.
If working out how best to inflate tyres to account for load, speed and off-road conditions seems like too much of a headache, a Jim’s mobile tyre shop technician can check your tyres and discuss your likely driving conditions and usage. They can then ensure your tyres are inflated appropriately.
How to adjust your tyre pressure
Most service stations have a digital tyre pressure gauge available for customer use. They are usually a flat surface, which is helpful for an accurate tyre pressure check. Checking your tyre pressure should take 5-10 minutes.
- The first step is to check the vehicle tyre placard sticker on the inside of your driver-side door for the recommended PSI. (Again, check your vehicle’s owner manual or fuel filler flap if you can’t find it in the door.)
- Set the pressure on the tyre pressure gauge, according to the recommended PSI.
- Take the air hose to your tyre, unscrew the cap from the tyre valve and attach the hose to the tyre valve (there’ll be a snap as it locks into place). If you hear hissing, it’s not properly attached.
- Leave the air hose attached until you hear a beep, which means your tyre has reached the programmed pressure.
- Remove the air hose and replace the tyre valve stem cap.
- Repeat for all 4 tyres, remembering that recommended PSI usually differs between front tyres and rear tyres. Remember to occasionally check the pressure of your spare tyre too.
- Return the air hose to the tyre pressure gauge and leave everything tidy!
How often should you check tyre pressure?
It’s worth checking at least once per month, and also before heading off on longer journeys, or journeys where you’ll carry a high load. This may sound excessive, but things can happen as you drive you may not be aware of, and tyres losing pressure is a good indicator of problems. Also, your tyres will naturally lose a little bit of pressure with regular driving, so checking on a routine basis matters.
Certainly don’t wait for your car’s 6 month or annual service for a tyre pressure check!
Also remember to check the tyre pressure of your spare tyre, as they can lose tyre pressure even when not in use. You don’t want to be caught with a flat spare when your actual tyre fails.
Jim’s tyre services
Don’t want to do it yourself? Jim’s Mobile Tyres technicians can provide tyre pressure checks and adjust your tyre pressure at a location convenient for you. We also provide a range of other tyre services including tyre repair, tyre rotation, new tyre fitting, and emergency breakdown repair. Give us a call and our mobile tyre shop will arrive at your door!