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Trailer Speed Symbols: Learn what the trailer symbols mean

Ever looked at the sidewall of your trailer tyres and seen a random letter like “L” or “N”?That’s your speed symbol — and it’s more important than you might think.

These little letters tell you the maximum speed your tyre can safely handle while carrying its rated load. Go faster than that, and you’re not just pushing your luck — you’re risking a blowout, an accident, or voiding your insurance.

Let’s decode them properly.



What Is a Speed Symbol?

The Speed Symbol indicates the maximum speed a tyre can safely sustain under its rated Load Index, according to the European Tyre and Rim Technical Organisation (E.T.R.T.O) standards.

It’s a key part of your tyre’s sidewall code — right next to the load rating — and it tells you how your tyres perform at different speeds and weights.

Here’s the official breakdown:

Speed Symbol

km/h

mph

J

100

60

K

110

69

L

120

75

M

130

81

N

140

87

P

150

93

Q

160

100

R

170

106

S

180

113

T

190

118

U

200

124

H

210

130

V

240

150

So, if your trailer tyre has an L rating, it’s safe for up to 75 mph — but that doesn’t mean your trailer should ever be doing 75 mph!


Trailer Tyre Rules: UK vs. EU

According to E.T.R.T.O. 1991 Section 13, caravans and light trailers can apply a special rule:

“An increase of 10% over the load capacity quoted in the tables is permitted when tyres are fitted to caravans and light trailers with a maximum operating speed up to 100 km/h (60 mph). The basic inflation pressure should be increased by 3 psi (0.2 bar).”

This means:

  • You can carry 10% more load if your trailer’s top speed is limited to 60 mph.

  • You must increase tyre pressure slightly to match that higher load.


However, this rule only applies within the UK, and not all manufacturers or sectors use it.

The UK light trailer industry often applies this 10% bonus, while the caravan industry tends to stick with standard load ratings at up to 130 km/h (81 mph).

So, always check your trailer’s manufacturer guidance — or play it safe and stay under both your load and speed limits.


Why Trailer Speed Symbols Matter

Tyres are your only contact with the road — and if they’re not rated correctly, you’re asking for trouble. Here’s why you need to pay attention to speed symbols:

  • Safety: Going beyond the tyre’s speed rating builds heat, which weakens the rubber and increases blowout risk.

  • Legality: The UK’s trailer speed limit is 60 mph, even if your tyres are rated higher — but the tyres still need to meet that speed safely.

  • Insurance: If your trailer’s running on under-rated tyres, insurers can refuse claims after an accident.

  • Maintenance: Proper inflation (and respecting that +3 psi rule when applicable) extends tyre life and performance.


Brent’s Take

At Brent, we’re all about towing smart — not just fast.

Understanding your trailer’s tyre speed symbols helps you stay safe, compliant, and confident every time you hitch up. It’s not the sexiest part of trailer ownership, but it’s the bit that keeps your wheels — literally — on the road.

If you’re ever unsure, check your tyre markings or ask your local hire outlet. And if your current setup looks a bit tired (pun intended), you can always find road-ready trailers on Brent — fully compliant, tested, and ready to roll.

Tow safe. Tow smart. Tow with Brent.


-Master Brent


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