Club 80-90 Forums

CycloneMike wrote:My understanding is that the Gross Train Weight or GTW is the maximum permitted or total combined weight of towing vehicle and trailer. This is effectively the total weight that the towing vehicle is capable of moving, (setting off, pulling along and stopping.) Which is why Land Rovers fair well due to their gearing and traction.
For example if the GTW for a T25 is listed at 3900kg, this equates to the Gross vehicle weight (GVW) of 2400kg for a fully loaded T25 + 1500kg for a trailer, which is probably where the 1500kg figure often quoted comes from.
So whilst it may be possible for an un laden T25 of about 1400kg to move a 2500kg trailer within its GTW, because 1400+2500=3900, it is not necessarily safe and could be considered dangerous. This is why there is an 80% guidance. It is not law but a safety recomendation advising that the trailer should not weigh more than 80% of the the actual weight of the towing vehicle. So it may not be considered safe to tow a 1500kg trailer with an empty van.
The purpose of the advice is to prevent the dangerous "tail wagging the dog" scenario, where an over heavy trailer will "boss" the towing vehicle about. This can start with a slight trailer weave then quickly turn into disaster! Particularly in crosswinds, under braking or travelling down hill.

You may be within the GTW but you've exceeded the 1500kg max trailer weight so its ilegal. Not loading the vehicle to the full doesn't mean the trailer can loaded extra to compensate, you can't exceed any of the plated limits. Some cars have a GTW lower than their max gross weight and max trailer weight combined!

I think the 80% "rule" was eather started by, or just heavily recomended by the caravan club, in the UK atleast. Makes sence as since caravans have a low weight to size ratio so are probubly less stable than a big Ivor Williams so are possably more vonrable. The thing I don't get is how the current trailer liceance laws seem to be written so people CAN tow some caravans without extra training where as the more stable (and in my mind useful) commercal trailer isn't aloud - maybe I'm just bitter as I fall into these towing restrictions.

How do trailer brakes work?..
Over run trailer brakes are the most common on 750-3500kg trailers. They work by a mecanisum in the hitch that when compressed it applies the brakes via a rod/cable/hydrolics. The hitch gets compressed as the trailers momentum will try and push the car as it slows down. This also happens when the trailer is being reversed so theres a system that disconects the brakes when going backwards, think that might be in the trailers brake drums - very old trailers aren't automatic reverse so needed a pin on the hitch to achive this but its been ilegal to make trailers like that for decades - as british trailers don't have a logbook or MOT though who would ever know? Theres a hell of alot of braked trailers out there with defective brakes, sometimes with lots of components missing - probubly never cause any problems till they get crashed.

Hi Glen,

Thanks for that. A most readable explanation

So the part covered with the rubber boot just behind the hitch either operates a rod or cable or hydraulics to the brakes.

Getting a good mental picture now.....


many thanks

Syncro G wrote:You may be within the GTW but you've exceeded the 1500kg max trailer weight so its ilegal. Not loading the vehicle to the full doesn't mean the trailer can loaded extra to compensate, you can't exceed any of the plated limits. Some cars have a GTW lower than their max gross weight and max trailer weight combined!

I think the 80% "rule" was eather started by, or just heavily recomended by the caravan club, in the UK at least. Makes sence as since caravans have a low weight to size ratio so are probubly less stable than a big Ivor Williams so are possably more vonrable.

Glen I am in total agreement with you, of course you should not exceed the manufacturers recommended trailer weight. I was trying to explain that you can't use an empty van to give more trailer capacity.

The Caravan Club Club do push the guidance. But it is also used by other motoring groups, such as classic car groups and horse owners who use Ifor Williams trailers. A tonne of feathers weighs the same as a tonne of lead. Disregarding cross winds, a mini digger on a plant trailer can be just as dangerous as a caravan on the back of the same towing vehicle in the wrong hands. The instability of caravans is often due to them being badly loaded, they also can have a greater pendulum effect due to length either side of the axle(s), once they start to sway.

Certainly up here VOSA are actively stopping trailers. Both to look for Tacho offences and trailer defects.

Oorwullie Is Switzerland really that exciting?

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sometimes.

but anyone pulling a trailer weighing a ton with no brakes here will probably find it expensive.