North Wales Police have issued a safety warning to drivers after road checks in Bangor found a number of vehicles with defective tyres.


Officers from the North Wales Roads Policing Unit, assisted by specials officers, stopped the vehicles in Bangor yesterday, Tuesday 6 August, to check roadworthiness and documents. A number of offences were identified but the condition of tyres was a recurring theme.

Not only are worn or defective tyres a safety risk but drivers also risk a £2,500 fine and three penalty points for a worn tyre. If all four tyres are worn below the legal limit, you could potentially lose your licence and face a £10,000 fine.




Legal & expert-recommended minimum tyre tread depth

The law requires car tyres to have a minimum tread depth of 1.6mm in a continuous band around the central three quarters of the tyre, although safety experts believe the 1.6mm legal minimum is insufficient to guarantee safety – most recommend a minimum tread depth of 3mm for tyre replacement.

Tests by UK technical organisation MIRA found that, once tyres are below 3mm, stopping distances increase dramatically. The difference in wet braking distance between a tyre worn to 3mm and one worn to 1.6mm can be as much as 44%.

Worn tyres are particularly dangerous in the wet because a tyre’s tread helps disperse water away from the contact patch between tyre and road.

If there’s less tread depth, less water can be shifted, increasing the risk of aquaplaning and losing grip.

In heavy rain, each tyre can shift one gallon of water every second, illustrating just how hard tyres work.

Simply put, deeper tread means they can work better, improving grip.

How to check tyre tread depth – the 20p Test

The 20p test is a simple, quick and easy way of checking the tyre tread of your car’s wheels.

Just take a 20p coin and insert it into the tread grooves on the tyre.

If you can’t see the outer band on the coin, your tyres are above the legal limit.

However, if you can see the band and that section of the coin is still visible, your tyres could be unsafe and require professional inspection by a mechanic.

The RAC suggest drivers conduct the 20p test around every two weeks and before long journeys.

Other legal requirements

Generally, with some exceptions for agricultural vehicles etc., it’s against the law to use a tyre that:

  • is not suitably inflated for the use to which the vehicle or trailer is put.
  • has a cut in excess of 25mm or 10 per cent of the section width of the tyre, whichever is the greater, deep enough to reach the ply or cord.
  • has a lump, bulge or tear caused by separation or partial fracture of its structure.
  • is unsuitable in regard to the vehicle’s use or to the types of tyres fitted to the other wheels (this does not apply to temporary use spare tyres).
  • has any portion of the ply or cord exposed.
  • is not maintained in fit condition for the use to which the vehicle or trailer is put.
  • has a defect that might cause damage to the road surface or to persons on or in the vehicle or using the road.

Photos: PC Scott Martin (North Wales Police)