Frequently Asked Questions
- How common is improper tire inflation?
- What is the correct tire pressure for my vehicle and where do I find it?
- What is the significance of the tire pressure listed on my tire sidewall?
- Can I tell if my tires are improperly inflated by looking at them?
- What are the effects of tire under-inflation?
- How do I know if my tires need inflating?
- How do I measure my tire pressure?
- How often should I measure my tire pressure?
- Should I ask a gas station attendant to measure my tire pressure?
- Why should I care about tire inflation when I have never had any problems with my tires?
- When should I measure my tire pressure?
- When should I measure my tire pressure?
- What should I do if my tires are over-inflated?
- What are the .big picture. environmental problems related to tire inflation?
- How does under-inflation affect my pocketbook?
- Does driving speed affect tire wear?
- What is the impact of mis-inflation on fuel consumption?
- Does temperature change affect tire pressure?
- What cost savings come as a result of proper tire maintenance?
- Why should I check my alignment?
- Why should I rotate my tires?
- How often should I rotate my tires?
- Why should I check my tire tread wear?
- How do I check the tread depth of my tires?
- How often should I replace my tires?
- If I replace my tires with a different quality or brand of tire, do I inflate them to the same pressure?
- What is a Tire Pressure Monitoring System (TPMS)?
- Do I have to measure tire pressure if my vehicle has a tire pressure monitoring system?
- What are the elements of a good tire maintenance program?
- Where can I get more information on proper tire maintenance?
A study conducted in early 2003, 2005 and still in 2007 found that more than two thirds of cars in Canada have at least one tire that is either under or over-inflated. One third of all vehicles had three or four tires that were improperly inflated. This represents a safety risk to Canadian motorists, as well as significant expenses in fuel and tire replacement costs. The resulting increase in fuel consumption means that more greenhouse gases, which contribute to climate change, and other harmful emissions are unnecessarily released into the environment.
Correct tire pressures vary from vehicle to vehicle and wheel to wheel. The recommended pressure for your vehicle is listed on the vehicle placard often located on the inside post of one of the doors or inside the glove compartment, trunk, or fuel door. Your owner’s manual will either give you the correct tire pressure or direct you to the placard’s location.
Do not use the tire pressure imprinted on the tire sidewall. That number refers to the maximum tire pressure, not the recommended tire pressure.
To measure your tire pressure, use a good quality tire gauge. A visual check is not an appropriate way to measure your tire’s pressure.
Find your Vehicle Information Placard
The pressure listed on the tire sidewall is the maximum tire pressure - or the tire pressure that is required to carry the maximum load of the tire. It is not the vehicle manufacturer’s recommended tire pressure, which is a common misperception. To find the correct tire pressure, consult the vehicle placard which is often located on the inside post of one of the vehicle’s doors or inside the glove compartment, trunk, or fuel door. Find your Vehicle Information Placard
No. It is a common misperception that a visual check of your tires is sufficient to measure tire pressure. Tires may be significantly under or over-inflated by up to 20% and yet, you may not be able to tell just by looking at them. Using a good quality tire gauge is the best way to correctly measure tire pressure.
The only accurate way to know if your tires need to be inflated is by measuring their pressure with a reliable tire gauge. Tire gauges are available at most automotive supply and hardware stores.
It is a common misperception that a visual check of your tires is sufficient to measure tire pressure. Tires may be significantly under or over-inflated by up to 20% and yet, you may not be able to tell just by looking at them.
Find the recommended inflation pressure for your tires on the vehicle placard. Check the owner’s manual for its exact location.
Only measure pressure when the tires are cold. Tires are cold if they have not been driven for more than 2 km or have been stationary for at least 3 hours.
Complete tire inflation pressure check: Remove cap from valve on one tire, press tire gauge onto valve and take pressure reading.
Add air to achieve recommended air pressure. If you overfill the tire, release air by pushing on the metal stem in the center of the valve, then re-check the pressure.
If you have to drive to get air, record the pressure first, drive to the station, take a second reading of the tires pressure and add the amount of air that was missing from the first reading.
WARNING: Avoid driving on seriously under-inflated tires for your own safety and to prevent damaging the tire.
Replace the valve cap and repeat with each tire, including the spare.
Measure your tire pressure monthly. Tires are permeable and tend to lose about 2 psi (14 kPa) per month, so it is important to regularly measure their pressure. Tires also lose pressure as the air temperature drops (about 1 psi for every 5°C drop in temperature), so remember to measure your tire pressure year-round.
Factors Affecting Pressure
While it is not difficult to measure your own tire pressure, it is reasonable to ask a gas station attendant to check them for you, if you prefer. They should be as willing to do this as they are to check your oil. However, make sure they use a reliable tire gauge, as the do it yourself pressure gauges at services stations do not necessarily function reliably. However, do not forget that if you have been driving for more than 2 km within the last 3 hours, your tires will have warmed up and you will obtain a less accurate reading than if your tires were cold.
Tire manufacturers produce highly engineered and reliable products, therefore most drivers have not experienced major problems with tires. However, proper tire maintenance remains a serious issue.
Improper maintenance can result in unsafe driving. For instance, under-inflated tires are more likely to suddenly fail (blow up) than are properly inflated tires. Tire air pressure supports 95% of the weight of your vehicle whereas the tire material only supports 5% of the weight of your vehicle.
Without enough air, the sides of a tire bend and flex too much. This builds up heat, which can cause serious damage to the tire and puts your safety at risk. In addition, proper tire maintenance practices can help you save money by extending the longevity of your tires, and reduce the environmental impact of operating a vehicle.
Properly maintained tires help vehicles operate more efficiently, optimizing the vehicle’s fuel efficiency. Lower fuel consumption also reduces the amount of greenhouse gas emissions that are released into the environment.
Proper Tire Inflation
Measure your tire pressure when your tires are cold, that is when you haven’t driven more than 2 km or your vehicle has been stationary for at least three hours.
Yes. One of the biggest tire maintenance-related myths is that over-inflation is not a problem. Often, even people who understand that under-inflation is a problem are unaware of the harmful effects of over-inflation.
An over-inflated tire rides on just the centre portion of the tread. The smaller contact area means reduced grip on the road leading to a harsh ride, handling issues (such as steering and stopping problems) and increased wear on tires and suspension components.
If you find that your tires are over-inflated, release air by pushing on the metal stem in the center of the valve, then re-measure the pressure. Never reduce pressure when tires are hot. Wait until they are cold, meaning that your vehicle has been stationary for at least 3 hours or has not been driven more than 2 km.
Annually, 643 million litres of extra fuel are consumed by Canadian vehicles because of improper tire maintenance practices. As a result, over 1 million tonnes of carbon dioxide are unnecessarily released into the environment. Canadians dispose of 29 million used tires every year, which has a significant impact on landfills. Even modest improvements in extending tire life could have a significant positive impact on our environment as energy used to produce new tires emits harmful pollutants into the atmosphere.
If tires are properly maintained, over the average life span of a vehicle, you can actually save yourself one to two sets of new tires because of lower wear and reduced fuel costs.
Fuel consumption increases by 1% for every 5% of under-inflation. Driving a vehicle with just one tire underinflated by 8 psi (56 kPa) will increase fuel consumption by 4%. Maintaining proper tire pressure could save you approximately two weeks of fuel a year, enough to pay for one full set of tires over the typical seven-year life of a vehicle.
Under-inflation also reduces tire life. Driving with tires that are under-inflated by 8 psi (56 kPa) will increase tire wear by 16% (approximately 15,000 km). This will hit your pocketbook as you will have to replace tires sooner than you would if they were properly maintained.
Yes, driving speed has a significant impact on tire wear. For instance, drivers whose average speed is 110 km/h will wear their tires about 25% faster than those driving at an average of 90 km/h. Frequent quick accelerations and abrupt stops can also increase tire wear.
Canada’s 17.6 million light duty vehicles consume roughly 38.3 billion litres of fuel annually, an average of 2,060 litres each. Tire rolling resistance is one of the main factors that affects fuel consumption. Fuel consumption increases by 1% for every 5% of under-inflation. Based on the weighted average of under-inflated tires, that translates to 643 million litres of fuel and costs Canadians over 800 million dollars of unnecessary fuel very year.
On an individual level, operating a vehicle with just one tire under-inflated by 8 psi can reduce the life of the tire by 15,000 km and can increase the vehicle’s fuel consumption by 4%.
Changes in air temperature cause changes in tire pressure, which is especially important given Canada’s climate. Every 5° C change in temperature results in about 1 psi change in pressure, so a temperature drop of 15° C would result in approximately 3 psi under-inflation. Therefore, it is very important to measure your tire pressure at least once a month, year-round.
If tires are properly maintained, over the average life span of a vehicle, you can actually save yourself the cost of one to two sets of new tires because of less wear and reduced fuel costs. Annually, improper tire maintenance practices unnecessarily cost Canadians over $800 million.
Having just one tire improperly inflated can result in an increase in fuel consumption that equals an average of two "free" weeks worth of gas per year.
Proper alignment is an important part of tire maintenance. Poor alignment will cause your tires to wear unevenly and you may experience handling problems such as .pulling. or vibration. Poor alignment will also increase your fuel consumption. You should have your alignment checked annually, or every 25,000 km.
Front and rear tires wear differently, especially on front wheel drive vehicles. Tires will last longer if you rotate them regularly. Please check your vehicle’s owner’s manual for the proper tire rotation schedule.
Rotate your tires on a regular basis. Check your owner’s manual or consult a service technician to find out how and how often your vehicle’s tires should be rotated.
It is extremely important to check your tire treads as proper treads allow for normal handling of your vehicle and help prevent skidding and hydroplaning.
Try the Bluenose test: place a dime in the tire’s groove with the Bluenose’s Sails facing down . If you can see the top of the Bluenose mass and sails, then your tires have sailed long enough and needs replacing. However, this test will not work with performance or off-road tires.
Tires are manufactured with .wear bars. The bar becomes exposed when there is less than 1.6 mm of tread depth remaining on your tire. Tires must be replaced when the wear bar is visible and even with the neighbouring tread block.
Tires usually last for between 60,000 to 130,000 km, but a number of variables affect the life of your tires, including average driving speed, weather, the type of roads you drive on and how well you maintain them.
Tires are manufactured with wear bars. The bar becomes exposed when there is less than 1.6 mm of tread depth remaining on your tire. Tires must be replaced when the wear bar is visible and even with the neighbouring tread block.
If I replace my tires with a different quality or brand of tire, do I inflate them to the same pressure?
As long as the tires are the same size as the last set, you should inflate them to the same pressure.
Tire quality and brand do not affect the recommended pressure. To find the correct tire pressure, consult the vehicle placard which is often located on the inside post of one of the vehicle’s doors or inside the glove compartment, trunk, or fuel door. Check your owners manual if you cannot find it.
Some new vehicles are equipped with tire pressure monitoring systems, which indicate when a tire becomes under-inflated. Some tire pressure monitoring systems provide a warning only when a tire is significantly under-inflated. The tire may be close to failure. Make sure you understand the tire pressure monitoring system installed on your vehicle. Consult your owner’s manual for more detailed information.
Tire Pressure Monitoring Systems (TPMS)
Yes. Even with a tire pressure monitoring system, it is still important to measure your tire pressure monthly. Tire pressure monitoring systems only alert you that there is a problem when your tires are under-inflated by 25-30%, which could represent a safety hazard.
Check tread wear