When Should You Replace Your Tyres? Seven Signs to Look For

Your tyres are the only parts of your vehicle that remain in contact with the road. Their condition directly influences braking, steering, handling and grip, particularly during wet Victorian weather.

Tyre deterioration is not always obvious from behind the wheel. A car may still feel relatively normal even when the tread is approaching its legal limit or the sidewalls have developed damage. Regular checks can help you identify problems before they affect vehicle safety or result in a failed roadworthy inspection.

Here are seven signs that it may be time to replace your tyres.

1. Victoria’s Minimum Tyre Requirements

For light vehicles with a gross vehicle mass of 4.5 tonnes or less, Victorian guidance requires tyres to have at least 1.5 mm of tread in all principal grooves, except at the tread-wear indicators. The principal grooves are the wide grooves generally found through the central portion of the tread.

Where tread-wear indicators are fitted, the tyre must not be worn to the point that an indicator contacts the road. Tyres must also be free from excessive uneven wear and damage or deterioration likely to cause failure.

These are minimum roadworthiness requirements—not targets for optimum performance. A tyre may become noticeably less effective in wet conditions before its tread reaches 1.5 mm. Drivers should consider the tyre’s complete condition and intended use rather than waiting until the legal minimum is reached. Current requirements are outlined in Transport Victoria’s tyre maintenance guidance.

2. The Tread Is Approaching the Legal Minimum

Tread grooves disperse water from beneath the tyre and help maintain contact with the road. As the tread wears down, the tyre’s ability to manage standing water may decrease.

Many tyres include tread-wear indicators moulded into their principal grooves. When the surrounding tread becomes level with one of these raised bars, the tyre has reached its wear limit and needs replacement.

Check each tyre in several places across its width and around its circumference. Measuring only one easily visible section may overlook a worn inner edge or isolated patch.

While 1.5 mm is Victoria’s legal minimum in the principal grooves, you do not need to wait until your tyres reach that point. Replacement may be sensible earlier if wet-weather performance has declined or you frequently travel in demanding conditions.

3. The Tread Is Wearing Unevenly

One section of a tyre can wear significantly faster than another. Common patterns include wear along an inner or outer edge, through the centre or in irregular patches around the tread.

Uneven wear may be caused by:

• Incorrect tyre pressure
• Poor wheel alignment
• Worn steering or suspension components
• Wheel-balance problems
• Bent or damaged components
• Driving habits

Victorian guidance states that a tyre must not have excessive uneven wear. More importantly, an unevenly worn tyre may provide inconsistent grip even when some sections still have substantial tread.

Replacing the tyre alone may not solve the problem. Ask a mechanic to identify the underlying cause and determine whether wheel alignment or suspension repair is required. Otherwise, the same wear pattern may quickly develop on the replacement tyres.

4. You Notice Cracks, Cuts or Bulges

Tread depth is only one measure of tyre condition. The tread and sidewalls should also be checked for cracks, deep cuts, exposed internal material, bubbles and bulges.

A bulge can indicate that internal components have been damaged, potentially after striking a kerb or pothole. This type of structural damage may increase the risk of sudden tyre failure and should not be ignored.

Cracking can develop as rubber deteriorates through age, heat, sunlight or environmental exposure. Small superficial marks should still be assessed if you are uncertain about their significance.

Official Victorian guidance states that any tyre with deep cuts, cracks, bulges or other defects likely to cause failure must be removed from the vehicle. Do not continue driving on a visibly damaged tyre simply because it still has legal tread.

5. The Tyre Repeatedly Loses Pressure

Tyres naturally lose a small amount of pressure over time, but frequent or significant pressure loss can indicate a problem. Possible causes include a puncture, faulty valve, damaged wheel, bead-sealing issue or structural damage.

Continually adding air does not fix the underlying fault. Underinflation can cause excessive flexing and heat build-up while accelerating wear along the tread shoulders. It may also affect steering response and fuel consumption.

Check pressures when the tyres are cold and follow the vehicle manufacturer’s recommendations, usually found on a placard inside the driver’s door opening or in the owner’s manual.

Some punctures can be repaired after the tyre has been removed and inspected internally. Damage near the sidewall or shoulder generally cannot be repaired using the same methods as an eligible puncture in the central tread area.

6. The Rubber Has Become Aged or Hardened

A tyre can deteriorate even when the vehicle is rarely driven. Exposure to sunlight, fluctuating temperatures and long periods of inactivity can cause the rubber to harden and crack.

The manufacturing date can be identified from the code marked on the sidewall. The final four digits generally show the week and year of manufacture. For example, “2424” indicates that the tyre was manufactured during the 24th week of 2024.

There is no single replacement age that applies to every tyre. Storage, driving conditions, maintenance and manufacturer guidance all affect service life. Age should therefore be considered alongside tread depth and physical condition.

If older tyres show cracking, hardening or reduced grip, arrange a professional inspection even if they have travelled relatively few kilometres.

7. The Car Vibrates or Handles Differently

New vibration, pulling, instability or unusual road noise can indicate a tyre or wheel problem. Possible causes include uneven wear, incorrect balance, deformation or internal tyre separation.

These symptoms may also be related to wheel alignment, steering components or suspension damage. A complete inspection is therefore more useful than assuming the tyres are solely responsible.

Stop driving and seek assistance if a vibration begins suddenly or becomes severe. Continuing to travel at speed with a potentially damaged tyre may increase the risk of further deterioration.

A mechanic can inspect the tyres, wheels and suspension to determine whether balancing, alignment, suspension repair or tyre replacement is required.

The Tyre Is Damaged Beyond Safe Repair

Not every puncture can be repaired. Under Victorian guidance, permanent tyre repairs are permitted only within a suitable part of the crown or central tread area. Repairs are not permitted in the bead, shoulder or sidewall.

A tyre generally should not be repaired if it has tread or casing separation, damaged or exposed bead wires, or cuts extending into its structural fabric. Tyres marked “Do not repair” must also be replaced.

For a proper permanent repair, the tyre must be removed from its rim so its internal condition can be inspected. External plugs, cords and tyre sealants may serve as temporary emergency measures in limited circumstances, but they are not substitutes for an internal assessment and approved repair.

If a puncture cannot be repaired safely, replacement is the appropriate option.

How Tyres Affect a Victorian Roadworthy Certificate

Tyres and wheels are checked as part of a Victorian roadworthy inspection. The assessment considers relevant safety requirements such as tread depth, excessive uneven wear, damage and general suitability.

A roadworthy certificate confirms that the vehicle meets specified minimum safety standards at the time of inspection. It is not a guarantee of overall mechanical reliability or how long the tyres will remain serviceable.

If you intend to sell, transfer or re-register a vehicle, having the tyres inspected before the roadworthy appointment can help identify obvious problems. Uneven wear may also justify checking the wheel alignment, steering and suspension before fitting replacements.

Should You Replace One, Two or Four Tyres?

The correct approach depends on the vehicle, tyre condition and manufacturer requirements. Replacement tyres must be suitable for the vehicle and have the correct size, construction, load rating and speed rating.

Tyres on the same axle should be appropriately matched. All-wheel-drive vehicles may also have specific restrictions concerning differences in tread depth or overall circumference.

Before replacing only one tyre, ask a tyre specialist or mechanic to compare it with the remaining tyres and check the manufacturer’s recommendations.

Help Your Tyres Last Longer

Check tyre pressures regularly and include a tyre inspection in every routine car service. Rotate tyres where recommended, address wheel-alignment issues and avoid harsh impacts with kerbs and potholes.

Most importantly, investigate uneven wear, vibration and pressure loss promptly. Tyres should be replaced when they are legally worn, structurally damaged or no longer suitable for safe use. If you are uncertain about their condition, arrange a professional inspection before the problem affects braking, handling or your ability to obtain a roadworthy certificate.