Safety First, how to identify worn out tyres

Road safety starts, first and foremost, with the contact between the tyre and the road surface. It is through this contact patch that braking, acceleration and cornering forces are transmitted. The condition of the tread has a direct impact on grip and braking performance. With normal use, the tread gradually wears down until it reaches the minimum limit set by law, making regular tyre inspections essential. Excessively worn tyres reduce braking performance, particularly in wet conditions, and increase the risk of aquaplaning, two factors that are fundamental to driving safety.
For this reason, recognising tread wear in good time is not simply a technical consideration for industry professionals, but a habit that should concern anyone who drives a car.

European regulations set the minimum depth of the main tread grooves at 1.6 millimetres. Below this threshold, the tyre can no longer guarantee adequate performance, especially on wet roads, and replacement becomes mandatory. Beyond the legal requirement, and in order to maintain a suitable safety margin regardless of changing weather conditions, it is generally recommended that tyres be replaced when tread depth reaches around 3 mm for summer tyres and 4 mm for winter tyres.

To make this check straightforward, tyres are fitted with small raised bars located at the bottom of the main grooves, each exactly 1.6 millimetres high. These are known as TWIs, or Tread Wear Indicators. As long as they remain below the tread surface, the tyre is still suitable for use. However, once the tread wears down and becomes level with these indicators, even at a single point around the tyre's circumference, replacement should no longer be postponed. To help drivers locate the TWIs, Pirelli marks their position on the sidewall with a small triangle.

Even before a visit to a tyre specialist, or when a professional measuring tool such as a tread-depth gauge is not available, there is a simple empirical method that can provide an indication of tyre wear: inserting a coin into the central groove of the tyre. Traditionally in Italy, drivers used a 500-lira coin; today, a one-euro coin serves the same purpose. If the central part of the coin is still covered by the tread, there is remaining depth available. If it remains visible, the tyre has likely reached its wear limit and replacement should be considered. While this method provides only a rough indication and cannot replace a professional inspection, it can be useful when no other alternatives are available.

Tread depth is the most obvious indicator, but it is not the only one worth monitoring. A regular visual inspection should also include the tyre sidewalls, including the inner sidewall, which is often overlooked because it is less accessible. Cuts, bulges, cracks or signs of ageing are all warning signs that can compromise tyre integrity even when tread depth remains within legal limits. An older tyre, despite showing relatively little wear, may lose elasticity and grip as a result of the natural ageing of the rubber compound.

Tread wear does not always occur evenly across the entire tyre surface. Wear concentrated in the centre of the tread usually indicates excessive tyre pressure, while more pronounced wear on the outer shoulders is often associated with underinflation. Localised or patchy wear patterns may instead result from wheel alignment issues, wheel imbalance or worn suspension components. Recognising these wear patterns helps not only to determine when tyres should be replaced, but also to identify underlying mechanical issues before they compromise safety or shorten the lifespan of a new set of tyres.

Except in cases of sudden and unforeseen damage requiring immediate replacement, tread wear progresses gradually under normal driving conditions. This gives motorists time to plan the purchase of a new set of tyres, compare the options available for their vehicle and decide whether to maintain the original equipment specification or opt for a different brand, tyre type or size, always within the limits specified in the vehicle registration documents. Planning ahead also allows drivers to check carefully that the quoted price includes fitting, balancing and disposal of the old tyres, as required by local regulations.

The timing of tyre replacement can also affect value for money. It is generally advisable to avoid the busiest periods at tyre retailers, when the availability of brands, models and sizes may be more limited and prices less competitive. This is often the case in the weeks leading up to the summer holiday travel period.

For winter tyres, summer is often the best time to buy, as retailers begin replenishing their stock ahead of the regulations that come into force each year on 15 November, requiring either winter tyres or snow chains on many stretches of the national road network. Purchasing tyres in advance does not necessarily mean fitting them immediately: installation can be booked for a later date, provided it falls within the required timeframe.

Regularly checking tread depth, together with tyre pressure, sidewall condition and wear uniformity, remains the simplest and most effective way to understand when it is time to replace your tyres.