How to Check Your Tyre Tread Depth: A Complete Guide for Somerset Drivers

Your tyres are the only part of your car that touches the road. The tread pattern is designed to channel water away and provide grip – but as it wears down, performance drops significantly. For drivers in Somerset, where wet weather is common and rural roads can be challenging, maintaining proper tread depth is essential for safety.

The Legal Minimum in the UK

In the UK, the legal minimum tread depth is 1.6mm across the central three-quarters of the tyre, around the entire circumference. This isn't just a recommendation – it's the law, and the penalties for driving with illegal tyres are severe:

• £2,500 fine per illegal tyre – that's potentially £10,000 if all four tyres are below the limit
• 3 penalty points per tyre – 12 points means an automatic driving ban
• Automatic MOT failure
• Invalidated insurance – meaning you're personally liable for any accident costs

The 20p Test: Quick and Easy

The simplest way to check your tread is with a 20p coin. Here's how:

1. Insert a 20p coin into the main tread groove of your tyre
2. Look at the outer band of the coin – if you can see it, your tread is too low
3. Check multiple points – test across the tyre width and at several points around the circumference
4. Repeat for all tyres – don't forget the spare if you have one

If the outer band of the 20p coin is visible at any point, your tyre is approaching or below the legal limit and needs replacing.

Why 3mm Is the Smart Replacement Point

While 1.6mm is the legal minimum, most tyre experts and safety organisations recommend replacing tyres at 3mm. Here's why this matters, especially for Somerset's challenging roads:

• Wet weather performance: At 3mm, stopping distances in wet conditions are already increased by approximately 25% compared to new tyres
• Aquaplaning risk: Below 3mm, the tread cannot effectively disperse water, dramatically increasing aquaplaning risk on flooded roads
• Rural road safety: Somerset's narrow lanes and unexpected conditions demand optimal grip
• Planning ahead: Replacing at 3mm means you can shop for the right tyres rather than rushing when you fail an MOT

Signs Your Tyres Need Attention

Beyond tread depth, watch for these warning signs:

• Uneven wear patterns: Could indicate alignment issues – common after hitting potholes on rural roads
• Cracks or bulges in the sidewall: Structural damage that means immediate replacement
• Vibration while driving: Could indicate internal tyre damage or balancing issues
• Age: Tyres should be replaced after 6-10 years regardless of tread, as rubber degrades over time

How Tread Depth Affects Stopping Distances

The difference in stopping distance based on tread depth is dramatic. In wet conditions at 50mph:

• 8mm (new tyre): Approximately 25.9 metres to stop
• 3mm: Approximately 35 metres to stop
• 1.6mm (legal minimum): Approximately 43 metres to stop

That's a difference of nearly 17 metres – more than four car lengths – between a new tyre and one at the legal limit. On Somerset's winding roads, those extra metres could be the difference between a close call and a collision.

Get Your Tyres Checked Free

Not sure about your tread depth? Pop into our Cheddar workshop or give us a call – we're happy to check your tyres and provide honest advice. No hard sell, just helpful guidance from your local tyre specialists.

We also offer mobile tyre fitting across Somerset, so if your tyres do need replacing, we can come to you at home or at work. Get a free quote today or call us on 01934 440410.