towing above 100% of kerbweight

[Rubix]

Much is said about novices not towing above 85%, and under no circumstance should anyone tow above 100%.

So why is it that some vehicles manuals state that you can tow much more than the actual vehicles kerbweight.

I know many 4x4s do , but some smaller cars do too.

Any ideas anyone, a scientific answer may be needed.

 

[JTQ]

The car manual gives you the weight it can physically tow and I think what it can haul up a 12.5% gradient.

It does not take any account of the dynamics of towing that weight, shape or mass distribution of trailer are, just that it can haul that mass.

You would I trust like to be safe to yourself, your unit and other road users and travel at reasonable speeds. Then with the character of a typical well sorted "caravan" many believe that you should limit the van weight to the order of 85% of the vehicles kerb weight for things to be safe.

I can haul around the yard a loaded farm trailer of 3.5 tonnes with my Land Rover but if I were idiot enough to go at 50 and 70 mph as permitted on a public highway I would need "certifying". Even if it was not illegal it would be a stupid thing to do.

 

[JTQ]

The car manual gives you the weight it can physically tow and I think what it can haul up a 12.5% gradient.

It does not take any account of the dynamics of towing that weight, shape or mass distribution of trailer are, just that it can haul that mass.

You would I trust like to be safe to yourself, your unit and other road users and travel at reasonable speeds. Then with the character of a typical well sorted "caravan" many believe that you should limit the van weight to the order of 85% of the vehicles kerb weight for things to be safe.

I can haul around the yard a loaded farm trailer of 3.5 tonnes with my Land Rover but if I were idiot enough to go at 50 and 70 mph as permitted on a public highway I would need "certifying". Even if it was not illegal it would be a stupid thing to do.

I meant of course 50 and 60 mph not 70!

 

[mcghee]

Many modern cars are capable of towing much more than there own weight. It is only a drivetrain limit which a manufacturer expresses, not a "safe" towing limit. I have in the past towed 6 tonnes with a Nissan Vanette 2.3, not recommended at not legal either, but probably safer than towing a caravan marginally heavier than your car. The reason for this is that a caravan has a relatively large profile in relation to its weight, and can be fairly easily thrown off course due to crosswinds. My advice would be don't try it.

 

[Lutz]

The manufacturers specify a towload limit that does not differentiate between different types of trailers, i.e. whether it is a caravan or a lowloader. Caravans, by virtue of their boxy design and relatively high centres of gravity as rather sensitive and therefore it is unwise to tow a caravan over 100% although another type of trailer may still be quite safe.