Evening all. Does anyone know why a car has a specified towing limit which is always more than the kerbweight? I always thought that a car cannot tow any trailer more than it's own weight. So why would a car which weighs 1500kg's have a towing limit of 1900kg's?
Towing Limits??
- Thread starter DanPaula
- Start date
The max tow capacity of your car is what the manufacturer has listed it will "safely" pull and brake on a certain gradient. Doesn't matter that it's over the car weight, as long as you've got the right driving licence and within max train weight you can legally tow it. That's the theory, in practice as a regular tow you'd be stupid to try it unless it was one of those that have a low max trailer weight compared to the vehicle's weight.
- Mar 14, 2005
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Not all cars have towing limits greater than their own kerbweight. In fact, a few even have a limit which is less than the 85% weight ratio recommendation.
The towing limit is not only determined by the car's ability to start or stop on a given gradient (a 12% gradient is the standard here), but it also depends on the what the vehicle engine's cooling system can handle as well as structural limitations of the underbody where the towbar is attached.
The towing limit is specified by the car manufacturer usually without regard for the type of trailer. Because a caravan is big and boxy it is more sensitive to instability than say a low loader trailer. It therefore placeds more demands on both car and driver. However, as some people only tow trailers other than caravans, the car manufacturer usually specifies an absolute limit which may be greater than 100%.
Some car manufacturers specify different towing limits for different gradients. Where this is the case it is often 8%, 10% and 12%. This is to allow heavier trailers to be towed in flat areas of the country. Also, Opel, for example, specify higher towing limits for some models if the trailer is less than 1.4m high. Although the very same models are also available with a Vauxhall badge, Vauxhall have chosen not to allow such a concession.
The towing limit is not only determined by the car's ability to start or stop on a given gradient (a 12% gradient is the standard here), but it also depends on the what the vehicle engine's cooling system can handle as well as structural limitations of the underbody where the towbar is attached.
The towing limit is specified by the car manufacturer usually without regard for the type of trailer. Because a caravan is big and boxy it is more sensitive to instability than say a low loader trailer. It therefore placeds more demands on both car and driver. However, as some people only tow trailers other than caravans, the car manufacturer usually specifies an absolute limit which may be greater than 100%.
Some car manufacturers specify different towing limits for different gradients. Where this is the case it is often 8%, 10% and 12%. This is to allow heavier trailers to be towed in flat areas of the country. Also, Opel, for example, specify higher towing limits for some models if the trailer is less than 1.4m high. Although the very same models are also available with a Vauxhall badge, Vauxhall have chosen not to allow such a concession.
Towing limits apply to all types of trailer, not just caravans.
As caravans are the least stable form of trailer the recommendation to never exceed 100% (it's not a rule) is appropriate for caravans - but other types of trailer where the weight is concentrated in the centre can safely exceed 100% IF it's within the car's towing limit.
As an example, my Subaru Outback has a kerbweight of 1520kg and a towing limit of 1800kg - I wouldn't dream of towing a caravan over 1520kg but I'd be quite happy with a car trailer at 1800kg.
As caravans are the least stable form of trailer the recommendation to never exceed 100% (it's not a rule) is appropriate for caravans - but other types of trailer where the weight is concentrated in the centre can safely exceed 100% IF it's within the car's towing limit.
As an example, my Subaru Outback has a kerbweight of 1520kg and a towing limit of 1800kg - I wouldn't dream of towing a caravan over 1520kg but I'd be quite happy with a car trailer at 1800kg.
One thing which is hardly ever mention when the topic of tow limits comes up is brakes!
I worry that a normal cars brake system can cope when it gets up to GTW, think of coming down an Alp or a pass in the Lake district in a Mondeo for example,with 1600kg on tow and the car stuffed to the limit with people and gear. In a word Scary!
That's one of the reasons I tow with plenty of capacity in hand.
I worry that a normal cars brake system can cope when it gets up to GTW, think of coming down an Alp or a pass in the Lake district in a Mondeo for example,with 1600kg on tow and the car stuffed to the limit with people and gear. In a word Scary!
That's one of the reasons I tow with plenty of capacity in hand.
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Braking performance on long descents is one of the criteria that the car manufacturers take into account when specifying towing limits. However, don't forget that the caravan has brakes of its own and if it is pushing hard enough against the car, its overrun brake will do the braking. The actual extra load on the car's brakes will therefore be limited unless the caravan's brakes have faded.
Coming down a mountain pass I've had the caravan brakes get so hot that the plastic wheelnut caps melted.
Coming down a mountain pass I've had the caravan brakes get so hot that the plastic wheelnut caps melted.
Yes I understand the theory Lutz.
Excuse me though for feeling safer going downhill in my vehicle towing at about half it's max tow.
Excuse me though for feeling safer going downhill in my vehicle towing at about half it's max tow.
Having experienced almost total brake fade in the Lake District in a mk2 Cortina, despite use of 1st gear, thank goodness modern cars just don't have the problem.
Using the gearbox correctly is the best way to avoid brake fade on steep hills.
Using the gearbox correctly is the best way to avoid brake fade on steep hills.
So you can tow a low trailer upto your towing limit but don't exceed kerbweight with a high sided trailer such as caravan. Correct???
It's not just the high sides that make caravans less stable, it's all the weight around the perimeter. Caravans have much higher yaw momentum than equivalent weight goods trailers where the load is concentrated in the centre.
- Mar 14, 2005
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Hi Dan and Paula
You would be legal from the weight point of view if you follow you adage posted 24 Mar 2008 05:38 PM, though strictly there is slightly more latitude, but that is nit picking.
However simply keeping to a certain weight ratio does not automatically give you a stable outfit. You must pay careful attention to the mechanical condition of the car and caravan, and load the caravan carefully to keep heavy weights close to the axle and away from the extreme ends of the caravan. And of course drive within the limits of the outfit and the driver.
You would be legal from the weight point of view if you follow you adage posted 24 Mar 2008 05:38 PM, though strictly there is slightly more latitude, but that is nit picking.
However simply keeping to a certain weight ratio does not automatically give you a stable outfit. You must pay careful attention to the mechanical condition of the car and caravan, and load the caravan carefully to keep heavy weights close to the axle and away from the extreme ends of the caravan. And of course drive within the limits of the outfit and the driver.
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