Trailer Safety

Horse trailer safety

If you betray a horse’s trust in you by not ensuring your trailer is safe, the consequences can be devastating. A horse will suffer terrible injuries if it goes through the floor or ramp, even if the trailer is parked, and faces risk of death if mechanical failure causes an accident.

In addition, an out of control car and trailer have the weight to do a lot of damage so this risks the lives of everyone in and around the car. Yet the UK has no trailer MOT test, so making sure a trailer is safe and legal is entirely down to the owner of the trailer. If you own a horse trailer here is what you need to check:

Horse trailer floors and ramps

Every few months lift the rubber matting and check the floors from above and below for damage and rot, using a screwdriver to prod suspect areas. While the mats are out, disinfect the floor and let it dry before replacing them.

Aluminium floors, though likely to be more resistant to deterioration than wood, still need checking and cleaning because they can also be damaged by horses kicking and may eventually corrode.

Never use a trailer with a suspect floor. Get the floor professionally replaced; horses put immense stress on it, so the correct materials must be used. Do not use a trailer without rubber matting because it helps spread the load and absorb impact.

Check ramps for damage and rot and if they start to flex more than they used to, have them replaced. Oil all hinges and latches.

Every few months lift the rubber matting and check floors

Horse trailer tyres

Correct tyre pressure on both car and trailer, are vital to outfit stability, so before every trip check them when cold with a pressure gauge. Car tyres should be the pressure recommended by the car manufacturer for towing or a full load. If neither is recommended, try inflating rear tyres to 3psi above normal as long as it is within the maximum shown on the tyre wall. An electric tyre pump plugged into the car’s cigarette lighter makes it easier.

While doing that, check for wear and damage. Tyres must have a minimum of 1.6mm of tread over the central 75 per cent of the tread width for the whole circumference. However, trailer tyres often perish long before tread wears out, so look for the telltale sidewall cracks. Bulges caused by air getting between layers of the damaged tyre, and cuts deep enough to show the reinforcing both indicate a potential blow out.

Never use and inner tube in a trailer wheel, because they deflate suddenly when punctured. Ensure replacement tyres have the correct weight rating

Correct tyre pressure, on car and trailer, are vital to outfit stability

Horse trailer lights

Trailer rear lights are the same as a car’s plus two triangular red reflectors, though there is normally no reversing light and older trailers do not have fog lamps. Trailers must have an illuminated rear numberplate, matching the towcar’s, and show two white lights to the front. Regulations cover the power and position of lights, so do not make any changes without checking. Lights must be clean and undamaged.

When you hitch up, check all the lights work. Always check indicators separately because hazard lights are usually on a separate circuit, so they work when indicators might not, and faults can make opposite car and trailer indicators flash.

Every six months, remove lamp lenses to clean the insides, removing corrosion from bulb contacts, and clean the plug and car socket contacts using a Hella Kleenaplug (from caravan dealers) or fine emery paper. Protect contacts with WD40 spray.

When you hitch up check all your lights work.

Horse trailer hitches and towballs

Towballs should be greased before use. Modern trailers have wear indicators in the hitches to warn of towball wear, so check that or get well used towballs measured by either a garage or a caravan or trailer dealer. Worn towballs increase hitch wear and can lead to trailers breaking free.

At least every three months clean dirty grease from the hitch cup with white spirit. When dry, smear clean grease in the cup and moving parts.

Every 3000 miles, use a grease gun to inject grease into the nipples in the drawbar housing behind each hitch. Some trailers also have a nipple underneath on the pivot of the lever that links the brake cables with the end of the drawbar.

Trailers are legally required to have breakaway cables

Horse trailer brakes and wheel bearings

Trailer brakes need adjusting for wear after 500 miles with a new trailer or new brake shoes, then every 2500 to 3000 miles. You must also check brake shoe wear, usually through holes in the backs of the drums, plugged with plastic bungs. Shoes need replacing when the friction material is down to 1.5mm.

Many modern trailers have sealed¬for-life wheel bearings, but older ones need bearings regreased and adjusted every two years.

The bearings are rings of rollers on which the wheels turn and may seize if not properly lubricated. To see which bearings your trailer has, carefully remove the cap in the wheel centre and if the nut underneath is castellated, with a pin through the slots, the bearings are the regreasing type.

Your trailer handbook should explain these jobs, as does the Allen Guide to Trailer Maintenance (see further reading) but if you doubt your ability to do it yourself, use a trailer or caravan dealer. Never work under a trailer supported on a jack or bricks.

Trailers are legally required to have breakaway cables, to apply the brakes if they become unhitched, which must be clipped to a purpose-made towbar ring or other substantial part of the car.

Horse trailer breakdown cover

Make sure you have breakdown cover for your trailer. Ordinary car breakdown cover excludes recovery of a trailer with horses aboard, so you could be stranded at the side of the road. RAC members can add Horse Trailer Assistance to their ordinary cover. Equestrian breakdown support is also offered by:

Horse trailer checklist

Every trip:

  • Tyre pressure and condition
  • Lights and indicators working
  • No loose or damaged fittings
  • Breakaway cable clipped to car

Every three months:

  • Clean and regrease hitch cup
  • Ramp condition
  • Clean and examine wooden floor

Every six months:

  • Clean lights and electrical contacts
  • Clean and examine aluminium floors

Every 2500 – 3000 miles:

  • Put grease in drawbar nipples
  • Check brake shoe wear
  • Adjust brakes

Every two years

  • Grease wheel bearings

About us

The Blue Cross and The Irish Blue Cross are leading equine and animal welfare charities, providing information, advice and practical support for pet and horse owners. In the UK The Blue Cross rehomes thousands of animals each year through its network of animal adoption centres. In Ireland The Irish Blue Cross is the sole provider of horse ambulance services to all Irish racecourses and to many equestrian events throughout the island, North and South. The Blue Cross hospitals in the UK, together with The Irish Blue Cross mobile clinics provide veterinary care for the pets of people who cannot afford private vets’ fees.

— Page last updated 23/04/2021

Did you find this helpful?

We provide free pet advice as every pet deserves to be well looked after. We treated around 35,000 sick injured and homeless pets last year. We're so glad we've been able to help these pets who are unable to help themselves, but there are thousands of sick and lonely pets still in need, so we need to ask for a small favour.

All of our work is funded entirely through donations. People like you are essential to our work. If everyone who benefits from our articles is able to give a little back, we can reach thousands more pets. For as little as £1 you can make a difference - do you have one minute? Thank you.