Trailer Tyre Sizes and Pressures: A Practical Guide for Safe Towing

When it comes to safe and reliable towing, your trailer tyres play a crucial role. The wrong tyre size, incorrect pressure, or simply poor maintenance can quickly lead to instability, blowouts, and dangerous handling on the road.

To help keep you safe (and legal), we’ve put together this practical guide to common UK trailer tyre sizes and their recommended pressures.

Why Tyre Pressure Matters

Maintaining the correct tyre pressure is vital for trailers of all sizes. Correct inflation ensures:

• Better stability on the road

• Even tyre wear and longer lifespan

• Reduced risk of blowouts under heavy loads

• Improved fuel efficiency when towing

Under-inflated tyres flex too much, heat up quickly, and can fail without warning. Over-inflated tyres, on the other hand, reduce grip and wear unevenly.

Common UK Trailer Tyre Sizes & Pressures

Below are the most frequently used trailer tyre sizes in the UK, along with their typical inflation pressures.

• 145/80 R10 → 60 psi

• 145/70 R13 → 50–55 psi

• 155/70 R12 → 50–55 psi

• 165 R13C (commercial rated) → 65–70 psi

• 175/70 R13 → 50–55 psi

• 185 R14C (commercial rated) → 65–70 psi

• 195/70 R14C (commercial rated) → 65–70 psi

• 205/70 R14C (commercial rated) → 65–70 psi

C-Rated Tyres vs Standard Car Tyres

You’ll notice some tyres are listed as C-rated (commercial). These are reinforced tyres designed for heavier loads, such as horseboxes, caravans, and large utility trailers. They require much higher pressures than standard car-type tyres, which are more common on lighter trailers.

Tips for Tyre Safety

• Check before every journey – trailers often sit unused for weeks, so pressures can drop without you noticing.

• Replace old tyres – even if they look fine, trailer tyres should be replaced every 5–7 years.

• Inspect regularly – look for cracks, bulges, or uneven wear.

• Match the load – always ensure the tyre load rating matches (or exceeds) the trailer’s plated weight.

Final Thoughts

Trailer tyres may not be the first thing you think about when preparing for a journey, but they’re one of the most important. The right size and correct pressure mean better handling, safer towing, and peace of mind on the road.

If you’re unsure about the correct tyres for your trailer, always check the manufacturer’s plate or handbook—or speak to a trusted trailer specialist.