HIGH-SPEED TRAILER TYRES

High-Speed Trailer tyres come in both modern Radial size markings, and also in older crossply (or Bias ply) size markings. Those with Radial sizes are written in a format similar to car tyres. Sizes will look similar to 155/70R13, where the first number represents the tyre width in mm, followed by the tyre 'profile', then its construction of 'R' for Radial, with the final number being the rim diameter in inches. Sometimes sizes are missing a profile number, such as 145R13, in which case its assumed the profile is 80% and the size 145R13 is therefore the same as 145/80R13.

Crossply (or Bias ply) high-speed trailer tyre sizes can come in a few formats. The simplest is the same as the Radial example about but the 'R' in the tyre size is swapped for a '-' to indicated its crossply/bias ply construction, i.e. 195/50-10. A second format is using imperial inches instead of metric mm, so sizes like 4.00-8, 5.20-10, 6.00-9, where the first number is the tyre width in inches and the last number is still the rim diameter in inches. The tyres profile is not in the size marking. The final format looks like 16.5x6.5-8, 18.5x8.5-8, 20.5x10.0-10, where the first number is now the tyres outer diameter (or height) in inches, the second number is the tyre width in inches, and the last number is the still the rim diameter in inches. 

Many radial high-speed trailer tyre sizes will end with the letter "C". This stands for Commercial rating, meaning that the tyre will carry far more weight than a car tyre of the same size. Not all manufacturers use this however, and some will use a Ply Rating or a Speed Load Index without a C to show that the tyre is suitable for higher load carrying. To be sure you have the right tyre make sure you match or exceed your current tyres load and speed index rating.

A high-speed trailer tyre's Speed Index is the maximum safe speed that the tyre is manufactured to travel at, and is represented by a letter from A to Z. The high-speed trailer tyre's Load Index is the maximum weight that the tyre can safely support, and is a one or two digit number. The higher this number is the more weight the trailer tyre can carry. It is imperative for the safety of the vehicle and its occupants that tyres with high enough Speed and Load Indexes are chosen. Check the Load and Speed ratings of your current high-speed trailer tyres before ordering replacements. The tables below show what each load and speed index number/letter relates to in KG and MPH.

A ply rating is another measure of a tyre's strength, indicating the maximum load that a high-speed trailer tyre can safely carry. Tyres with a higher ply rating carry more weight but cost more due to their superior construction and the extra materials used. A Ply Rating is normally only associated with crossply high-speed trailer tyres, not with modern Radial trailer tyres. That being said you may occasionally see or hear a ply rating being mentioned when discussing radial high-speed trailer tyres. This is simply a way to confirm or convey a tyre is in the same weight carrying class as any crossply tyre counterpart that may also be suitable to be used for your vehicle. With any load rating, ply or load index, always ensure you match or exceed your current high-speed trailer tyres rating. If your tyre only shows a load index rating and you find a matching replacement tyre with the same or greater rating then you will not need to worry about its ply rating. A load index is the modern way of expressing what a high-speed trailer tyre can carry and should always be checked before replacement.

• ROAD PATTERNS - Tyres for heavier trailers will often be similar to car tyres but with a higher load capacity. This pattern is normally found on the modern radial tyres and is ideally suited to larger road trailers.
• ZIG-ZAG PATTERNS - The Zig-Zag pattern is common on lighter trailers similar towables. It is a good all-round pattern designed for long service life without sacrificing road performance.
• LUG PATTERNS - Some trailer tyres, especially those designed to carry extra weight, will often have pronounced shoulder lugs for increased stability at high speed. This type of tyre is common on trailers using older or smaller wheels, and these are often available as Tube-Type tyres.

Tube-Type (TT) tyres need to have a separate tube fitted inside them to keep them inflated. The inner tubes are purchased separately to the tyre. Most radial trailer tyres however are tubeless (TL) by design, and inner tubes should never be fitted inside tubeless tyres used at high speeds as it presents a safety risk if they overheat and rupture. Tubeless tyres have their own inner liner which prevents leaks from the rim and minimises the damage done by punctures. Tubeless trailer tyres are more resistant to overheating, but air leakage can occur if the tyre has not been fitted properly or if the rims are old or damaged.

Tyre labelling is an EU requirement and scores high-speed trailer tyres in 3 main areas as follows:

• Rolling Resistance - The grades range from A to E, informing you about the relative fuel efficiency performance level. 'A' is the highest performance tyre in its category; 'E' is currently the least performing.
• Wet Grip - The grades range from A to E, informing you about the relative wet grip performance level. 'A' is the highest performance tyre in its category; 'E' is currently used to represent the least performing.
• External Noise - The tyre's exterior noise is expressed in decibels (dB) and will show one, two or three sounds waves. These sounds waves highlight the performance of the test against the current law. Three bars indicate that the tyre meets current limits, two bars indicates that the tyre meets limits that are to come into effect in the future and one bar shows that the tyre is a further 3dB below future limits.

Tyre labelling that was introduced in 2012 and requires every new passenger car tyre sold within Europe to be labelled. There are some exceptions which include retread tyres, professional off road tyres (POR), racing tyres, spare tyres and tyres with a speed rating less than 50 mph. The EU's aim being to significantly improve the efficiency and safety of road transport, and give consumers the ability to make more informed decisions when buying new tyres.

This category is for high-speed road trailer, caravan and other high-speed towables tyres. For agricultural trailer tyres, such as tyres for towed implements or large farm trailers, please check our Agricultural Tyres section. If you can't find what you're looking for then please Contact Us and we'll be happy to help.