How to know when to change tires: 9 steps

Table of contents:

How to know when to change tires: 9 steps
How to know when to change tires: 9 steps

Have you ever wondered if it's time to replace the worn out tires on your car? Tire performance is very important to maintaining the safety, performance and efficiency of a vehicle. However, at some point, the tires will start to wear out and lose their traction and stopping ability. Fortunately, if you're wondering when to start looking for new tires, there are some tips that can help you stay informed.


Method 1 of 2: Examine the Integrity of the Tread

Know when Car Tires Need Replacing Step 1
Know when Car Tires Need Replacing Step 1

Step 1. Check your state or region for tread recommendations

The main function of a tire tread is to divert water underneath to improve traction and prevent the vehicle from hydroplaning on wet roads. Once the tread is reduced to 2mm (2/32 of an inch), the tire will become unsafe and illegal in most areas of the world. Review the tread requirements provided by your state or region's ministry of transportation.

  • You can call or email your country's transport ministry or visit their website to find the laws about tread.
  • In some states in the United States, tires are considered legally worn when they taper to 1/16 inch (16 mm) of the remaining tread depth.
  • In the UK, the minimum depth for the tire tread is 11mm (0.0456 inches) along the center ¾ of the tread around the entire tire.
Know when Car Tires Need Replacing Step 2
Know when Car Tires Need Replacing Step 2

Step 2. Replace the tires if the tire bar is flush with the tread

All tires sold in the United States and most other countries have wear bars, which are small horizontal bridges that form between the treads at a shallower depth. As the tires wear, these bars even out with the tread. If the tire tread is level with these wear bars, it is worn to 2/32 of an inch (16 mm) and should be replaced immediately.

When looking at the tire wear bars, be sure to cover the entire surface of the wheel and not just one isolated location

Know when Car Tires Need Replacing Step 3
Know when Car Tires Need Replacing Step 3

Step 3. Check the tread for wear quickly by inserting a penny into it

Take a penny and lay it upside down with Lincoln facing you in the center of the tread on the thickest part of the tire. If you can see the top of Abraham Lincoln's head or the copper above it, you should replace the tire immediately. If you can't see the hair on Lincoln's head (which means the tire tread is at least as deep as his forehead), it doesn't need to be replaced yet.

  • If you have a Canadian nickel, you should insert it between the tread with the Queen Elizabeth crown facing down. If the top of the crown is visible, the tire is below 2/32 inch (16 mm) and needs to be replaced.
  • Tires don't wear evenly, so be sure to insert the coin at various points from the outside to the inside of the tires. Tires generally wear the most on the inside. However, over-inflated tires wear the most in the middle.
  • To get a more accurate measurement of tread depth, you can use a tread depth gauge.
Know when Car Tires Need Replacing Step 4
Know when Car Tires Need Replacing Step 4

Step 4. Use a tread depth gauge to get a more accurate measurement

Place the gauge sensor in the center of one of the tire grooves just outside the tread. Pull the caliper up the barrel, being careful not to touch the sensor, and note the depth of the tread. Continue this procedure for locations around the center tire grooves at least 15 inches (38 cm) apart, then average the numbers. Replace the tires if the depth is less than 2/32 inch (16 mm).

  • Repeat this procedure for the outer and inner circumferential grooves, and then average those figures as well.
  • To average the numbers, you need to divide the total by the number of individual measurements you made across the tread.
  • Before using the tread depth gauge, press the gauge against a flat, hard surface and make sure it reaches zero when fully compressed.
  • Avoid placing the tread gauge on any raised surfaces or molded tread wear indicators.

Method 2 of 2: Spot Signs of Tire Damage

Know when Car Tires Need Replacing Step 6
Know when Car Tires Need Replacing Step 6

Step 1. Have your car serviced if you notice uneven tread wear

This could indicate wheel misalignment, improper inflation pressure, the need for tire rotation, or all of the above. Regardless of the specific reason, uneven tread wear is a sign that you need to take your car in for repair.

  • If the uneven tire wear is extreme or the tires wear out much faster than expected, you should have the suspension checked and corrected as necessary by a competent garage before replacing the tires. Incorrect alignment or worn suspension parts can dramatically shorten the life of a tire.
  • Rotate the tires front to back in pairs to avoid uneven tread wear. Take both front tires and move them back and vice versa.
Know when Car Tires Need Replacing Step 7
Know when Car Tires Need Replacing Step 7

Step 2. Check for abnormal bumps or bubbles on the side band

The side stripe is the surface of the tire outside the rim that points towards you when the car is parked. A bulge indicates that the rigid inner frame of the tire has been damaged and cracked, allowing air pressure to reach the flexible outer layers of the tire. Any tire with bulging on the side bands should be replaced immediately, regardless of the condition of the tread.

  • Such damage can occur when driving over a large pothole, driving on a sidewalk, or with low tire pressure.
  • Never continue driving with a tire that has a bulge on the sidewall. This detail indicates that the structural integrity of the tire has been significantly reduced, greatly increasing the likelihood of a sudden failure or puncture at highway speeds.
Know when Car Tires Need Replacing Step 9
Know when Car Tires Need Replacing Step 9

Step 3. Balance the tires if you detect vibrations in the steering wheel

If your tires wear unevenly, you may notice a vibration in the steering wheel while driving. If the vibration starts between 65 and 80 km / h (40 and 50 mph) and intensifies as you increase speed, you will most likely need to balance your tires. If this doesn't stop the vibration, the tire is most likely damaged and needs a complete replacement.

  • If you experience vibrations in the absence of tread damage, try balancing and aligning the tire shock absorbers.
  • If you detect tire vibrations along with other indicators of damage (such as abnormal bulges and uneven tread wear), you may need to replace the tire.
  • If you notice that the tires are hollowed (which means they have a wavy appearance around them), it is likely that they are not rotated enough.
Know when Car Tires Need Replacing Step 10
Know when Car Tires Need Replacing Step 10

Step 4. Check for dry rot and have affected tires inspected or replaced

If you see small cracks all over the tires, it means the rubber is breaking. Tires with dry rot can crumble and separate from the steel belt, causing damage to the exterior of the car. In some cases, the wheels are likely to start rotting before the tread starts tapering off. You still need to bring them in for inspection or replacement.

  • You should check for dry rot before embarking on longer trips and bring the car in for a regular checkup.
  • Degrease the tires to prevent dry rot, especially if the tires are exposed to high sunlight.
Know when Car Tires Need Replacing Step 8
Know when Car Tires Need Replacing Step 8

Step 5. Replace the tires at least every 6 years

Check the 4-digit code on the tire band to find out how old it is. Regardless of your country, most transport ministries place 4-digit numbers on the tread of each tire. The first 2 numbers indicate the week it was manufactured and the last 2 indicate the year. For example, 08/12 means the tire was manufactured in week 12 of 2008. If the tire is more than 6 years old, it must be replaced.

  • If you're having trouble finding the number, look for the initials DOT, followed by other letters and numbers. The code should appear after the period and not have any letters.
  • Remember that although 10 years is the maximum service life for tires (from the date they were manufactured), this should never be used as the maximum driving time.
  • It is always best to exercise caution if you suspect that the vehicle has tires that are more than 6 years old.
  • Always change your tires if the tread is below the minimum depth recommendation, which is often 2/32 of an inch (16 mm).


  • Always keep your tires properly inflated.
  • The age of the tires is measured from the date of manufacture, and not of sale, since the tires deteriorate even during storage.
  • Test all tires and, if possible, replace them all at the same time. Uneven tires do not provide the same safety, performance, and efficiency as a well-aligned pair.
  • On four wheel drive cars, try to replace all 4 tires with the same type unless otherwise recommended in the service manual. Differences in tire diameter, even due to different states of tread wear, can permanently damage differentials.
  • Tread grades are an indicator of a tire's relative wear rate. The higher the tread number, the longer it will take to wear out.
  • Remember that tires deteriorate faster in warmer climates.
  • A quarter can be replaced by an American penny, just use Washington's head as a point instead of Lincoln's.


  • You must be careful when rotating the tires, especially when moving the tires to different wheels. Many modern tires have a specific direction of rotation and the corresponding rotation method. Check with the tire manufacturer or car dealer for details. However, you should be aware that some sports cars have different sizes of wheels on the front and rear, which means that they cannot be rotated.
  • If you notice cables on the tread or wear on the side bands of the tire, you should replace the tire immediately.
  • The tires should never rub against the fenders or any other part of the car. If new tires rub during corners or when going over potholes, it is because they do not fit properly and must be repaired.
  • Always make sure you buy tires of the correct size and type for your vehicle and wheels. Switching to low-profile tires may require you to buy larger wheels so that the outer circumference of the tire remains unchanged. The wrong tire size or uneven tread can also trigger a low tire pressure warning if the vehicle is equipped with a tire pressure monitoring system.

Popular by topic