What Is the Legal Tyre Tread Depth for Trucks and Trailers in the UK?

In the United Kingdom, the legal minimum tyre tread depth for heavy goods vehicles (HGVs), including trucks and trailers over 3.5 tonnes, is:

1 millimetre

This minimum tread depth must be present across a continuous band covering at least three-quarters (75%) of the tyre’s width and around the entire circumference of the tyre.

This regulation applies to:

• Rigid trucks

• Articulated lorries

• Semi-trailers

• Full trailers

• Buses and coaches

Important Technical Details

• The 1 mm requirement applies to the main grooves of the tyre.

• The tread must be visible and measurable.

• The rule applies to every axle, including trailer axles.

• Cuts, bulges, or exposed cords make the tyre illegal regardless of tread depth.

What Happens If You Drive Below 1 mm?

Driving with illegal tyres in the UK can result in:

• A £100 fine per illegal tyre

• 3 penalty points per tyre

• Possible prohibition notice (vehicle stopped immediately)

• Court prosecution for serious offences

For fleet operators, this can also lead to DVSA investigations and operator licence issues.

Is 1 mm Safe?

Although 1 mm is the legal minimum, it is not recommended to run tyres down to this limit.

Safety experts and fleet managers typically recommend replacing truck tyres at:

2–3 mm

Why?

• Better wet grip

• Shorter braking distances

• Reduced aquaplaning risk

• Improved fuel efficiency

• Lower risk of roadside inspections and penalties

How to Check Tread Depth Properly

You can measure tread depth using:

• A professional tread depth gauge

• A calibrated tyre depth tool

• Workshop inspection during routine maintenance

It is strongly advised to check tyres weekly for HGV vehicles.