Trailer Tyres

When you are getting ready for a trip it is vital that you do not overlook one of the most important safety aspects of your journey – the condition of your trailer tyres.

By law, all trailer tyres must comply with exactly the same regulations for condition and tread depth as every other tyre or van on the road. Replacement tyres must be capable of sustained running at 60mph with the trailer at its maximum gross weight (also referred to as MAM – Maximum Authorised Mass).

In the interests of added safety, it is also recommended that tyres of the same Size, Load Index and Speed Rating as the originals are fitted. This information can be found on the sidewall markings. The tyres do not have to be the same make. Radial and cross ply tyres must not be mixed on the same axle. It is also recommended, though not a legal requirement, they are not mixed between axles. However, if they are mixed, the radials should be on the rear.

Pressures must be maintained as recommended by the trailer manufacturer. Low tyre pressures are the most common cause of tyre failure and variations in pressure from tyre to tyre can adversely affect the handling of the trailer.

Spare wheels are not a legal requirement but if fitted the tyre has to comply with the regulations.

Etyres, the UKs leading online tyres retailer, has been supplying and fitting trailer tyres since the early 1990’s and we can help you get your trailer in good shape for the journey ahead.

Over the years, thousands of satisfied car, van, caravan, motorhome and trailer owners have returned to us time and again to place repeat orders knowing our prices are competitive.

And because we offer a mobile fitting service you don’t have to worry about driving to a garage or manoeuvring your trailer into a tight spot in a depot, because we come to you and fit your tyres on your doorstep.

We have put together a comprehensive guide to trailer tyres covering everything from inspections and maintenance to repairs and replacements, all with the aim of making travelling safer for you and your family.

Check Your Trailer Tyres

You must check your tyres regularly – not just before a long journey. Even if you have not used your trailer for some time the tyres may start to deteriorate and there are steps you can take to slow this process down.

First look out for any obvious signs of age deterioration in the tyres, such as cuts, lumps, embedded objects, sidewall cracking and carcass deformation. Trailer tyres that are on a stationary vehicle are always likely to age more quickly than those in regular and frequent use. Tyres exposed to coastal air are also prone to faster aging. Also pay particular attention to the tread depth. Trailer tyres, like all car and light commercial tyres, must have a minimum tread depth of 1.6mm in order to be legal and roadworthy. However, in the interests of safety it is advisable to replace tyres well before they reach this legal limit.

Check the Pressure

Checking the pressure in your trailer tyres is another vital step which is essential to the safety and stability of your vehicle.

Incorrect tyre pressure can have a catastrophic effect on the handling of the trailer and can also lead to dangerous tyre failure, including blow-outs.

Tyres that are incorrectly inflated will also wear out more quickly and also increase the vehicles fuel consumption. So running them at the correct level will also save you money!

The correct inflation pressure for your trailer tyres will be given in the manufacturers handbook.

Tyres pressure should be checked and adjusted, if necessary, when the tyres are cold. Never reduce pressures when the tyres are warm, because they could be too low when they cool down.

Find Out Your Tyres Age

Unless a lot of touring miles are covered it is unlikely the tyres on a trailer will ever wear out.

However, like all tyres, they will deteriorate with age and can become distorted if they are left unused in the same position. Also surface cracking of the sidewalls can occur if the tyres are allowed to become under-inflated and remain for a long period of time in that condition.

For this reason, leisure vehicle organisations recommend that trailer tyres should be replaced when they reach five years old and they certainly should not be used beyond seven years.

It is also worth noting that etyres only buys tyres from the manufacturer when they have been ordered by a customer. This guarantees that our customers are getting the most up-to-date stock, not tyres that have been gathering dust on a store room shelf in a large depot for several years. You do not want to waste money on “new” tyres that are already half way through their life expectancy before they even see sight of your trailer.

Follow these steps to find out how old your trailer tyres are:

  • Date of Manufacture is shown on the sidewall of all motorhome tyres as part of the DOT (U.S. Department of Transport) code found close to the wheel rim. Example of a code is DOT A87C DEF 699, the final set of three, or four, numbers being the date code.
  • Tyres made between 1990 an 1999 use a three digit code followed by a triangle and indicate the month and year in which the tyre was made (699 being June 1999).
  • From 2000 onward a four digit code is used to show the week and year (0102 being the first week of 2002).
  • A small number of tyres may not have the DOT code but in these cases the date of manufacture may still shown elsewhere on the tyre, for instance if you see as a separate group of letters 4202 that is definitely 42nd week of 2002.

Fit the Correct Tyres

Replacement tyres must be capable of sustained running at 60mph with the trailer at its maximum gross weight (also referred to as MAM – Maximum Authorised Mass).

Radial and cross ply tyres must not be mixed on the same axle. It is also recommended, though not a legal requirement, that they are not mixed between axles. However, if they are mixed, the radials should be on the rear.

In the interests of added safety, it is also recommended that tyres of the same Size, Load Index and Speed Rating as the originals are fitted. This information can be found on the sidewall markings. The tyres do not have to be the same make.

The Load Index is shown on the sidewall of all caravan tyres immediately behind the size coding and in front of the speed letter code. A typical example will be 175/80/R/13 97T.

175 is the tyre width in millimeters, 80 is the sidewall height, expressed as a percentage of the width. R indicates a radial type construction. 13 is the wheel diameter in inches. 97 is the Load Index. T is the speed rating.

Tyres Sidewall Markings

The diagram below shows the markings that can be found on a typical tyre sidewall.

* do not apply in the UK.

Trailer Tyres Load Index

The Load Index is a numerical code associated with the maximum load a tyre can carry at the speed indicated by its Speed Symbol under service conditions specified by E.T.R.O 1991, passenger car tyres section 13, reproduced below.

LI = Load Index and kg + Load (kg)

Trailer Speed Symbols

The Speed Symbol indicates the speed at which the tyre can carry a load corresponding to its Load Index under service conditions specified by the tyre manufacturer. For caravans and light trailers see conditions specified by E.T.R.O 1991, passenger car tyres section 13, reproduced below.

E.T.R.O 1991 – Section 13 – Caravans and Trailers:

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 (60mph). The basic inflation pressure should be increased by 3psi/0.2 bar.

This 10% bonus loading is widely used in the UK light trailer industry, but should only be used on trailers that are to be sold within the UK. The caravan industry in the UK tends to ignore this bonus loading and use loadings at 130 Km/h/ (81mph).

Trailer Load and Tyre Ratings

A table covering popular trailer sizes is given below.

Trailer Tyres Care

You can take steps to prevent early deterioration to your trailer tyres. These include:

  • Consider covering the tyres to shield them from direct sunlight.
  • Maintain the correct tyre pressure which will minimise the chances of sidewall damage and turn the tyre occasionally to prevent flat surfaces.
  • Cleaning with caravan shampoo will stop grime damaging the surface – but and avoid using pressure washers directly onto rubber, because the force of the water can degrade the rubber and cause problems when you’re on the road.

Punctures

The use of pre-puncture sealant is not recommended by the manufacturers. However, post-puncture sealants may serve a useful purpose in an emergency when its use can enable the driver to move the vehicle to a safer location.

It is also crucial to have the tyre on the other side of the axle examined, because it may have sustained damage while bearing an extra load.

Any tyre that has sustained a puncture and run – even for a limited distance – in a deflating or deflated condition is likely to have suffered internal damage and will be in need of replacement.

Tyron Safety Bands

Etyres fitters can also fit potentially life-saving Tyron bands, which are a simple but effective safety device used on tyres.

Tyron bands work by keeping the tyre on the wheel in the event of a puncture or blow-out, which will allow you time to drive to a safe place and stop to change the wheel.

Without the Tyron band the tyre would come off the wheel rim causing it to come into contact with the road and inflicting costly damage. Usually when a tyre collapses it causes an accident – and the higher the speed you are travelling at when the blow-out happens, the greater the chance of you suffering a catastrophic accident.

Having the safety bands fitted will give you extra peace of mind with the knowledge that if you suffer a puncture or your tyre deflates, you will still be able to maintain control of your trailer whatever speed you are travelling at.

It is also worth pointing out that the police and emergency services fit them to their vehicles – so they must be worth the expense.

etyres Top 10 Tyre Safety Tips for Trailer Owners

  1. Inspect tyres for signs of damage
  2. Check tread is more than the legal minimum of 1.6mm
  3. Ensure tyres are correctly inflated
  4. Check age of tyres – if over five-years-old consider replacing
  5. Fit tyres of the correct specification
  6. Avoid sidewall impact
  7. Don’ t overload trailer or you risk having a blow-out
  8. Care for and inspect tyres even when not in frequent use
  9. Check jack operation and add a drop of oil on the screw mechanism
  10. Remember, etyres mobile service covers the whole of the UK – so if you need help with your tyres when you are at home or on holiday call us on 0800 028 9000.