Monthly Archives: January 2015

Emergency caravan braking requires a learned skill!

caravan-braking-on-cornersHave you had to do a emergency caravan braking on a sharp corner? Or have you found that stray animal in the middle of the road at a bend and you have to brake and turn? If you have done this successfully you would most probably have applied the caravan or camper trailers brakes remotely from the vehicle first, then applied the vehicle brakes. Why?

If you apply the vehicle brakes hard and fast and turn the wheel, the vehicle will turn but the caravan or camper trailer is still in a straight-line. It will tend to push the rear of the vehicle out and induce a dangerous spin inertia on the vehicle.

If you apply the caravan brake hard and fast just a second or 2 before the vehicle, there is the reverse effect. The caravan or camper trailer acts like a large parachute on the rear and slows the whole turn inertia down. You feel more in control to get out of a difficult predicament.

Platinum offroad camper trailer

Platinum offroad camper trailer

For this to happen, you need 2 things:

  1. The brake controller in your vehicle has to be so close to where you normally keep your left or right hand. You need to be able to locate and slide/activate it fully without taking your eyes off the road.
  2. You need very good brakes on the caravan or camper trailer  that can apply fully braking and not fade.

For the first point, there are many electric brake controller installers that want to install the manual controller “out of the way” or on a dummy dash position that has minimum impact on how the vehicle looks. Please say “no thanks” unless it is the perfect position. If looks are a concern, here is an alternative: On a fairly expensive Range Rover, the author has a “hard shell velcro strip” on the top of the brake controller and this presses up on a discrete metal bracket with the matching “hard plastic” velcro. This sits just under the dash 100-150mm from where the left hand is on the wheel. It can be applied as fast as a flash. Several practice runs are made at the start of every trip to get the reflexes and “feel” just right. On every trip so far it has been used at least once!

Compliance-to-ADR-rules-for-brakingThe second point is the most important. The Australian Standard on braking stipulates a measurement of the effectiveness of the braking with a tow vehicle. The problem with this measurement is if you have a powerful tow vehicle, the caravan or camper trailer braking test will probably pass every time. The 6 pot disc brakes on the Range Range will even pull up an un-braked trailer within the standards. So this doesn’t give good assurances for emergency caravan braking when you are applying JUST the caravan brakes.

offroad-camper-trailer-air-suspension-2862-600x400-resized-600.jpgA simple way to measure how effective your brakes are is by doing an emergency “pit stop” at a low controlled speed and then measuring the distance covered. This is broadly how the Australian Design Rules describe the testing of Caravan and camper trailer brakes. Rule 128 stipulates the exact testing process. Manufacturers should do this on each model to ensure that they comply. Then do this on the caravan brakes only and you can compare it to our findings below. Please do this in a safe section of private road with no traffic. Use a maximum speed of 35klm/hr. No faster please!

Brake manufacturers issue guidelines from what they estimate their brakes should be able to achieve but we have never seen these documents state compliance to the Australian standard brake tests. Why not?

There are 9 factors that link the braking capability of your caravan or camper trailer with the braking outcome as described by the standard:

  1. The size of the wheels and tyres: a larger rolling diameter requires higher braking capacity
  2. The weight of the caravan or camper trailer: the heavier the weight, the higher capacity required
  3. The weight of the vehicle: The heavier the vehicle, the stronger the stopping capacity if the vehicles brakes are more effective
  4. The matched balance between the drivers and passenger’s side braking components and/or the electric signalling system: Any imbalance and the caravan or camper trailer will push to one side regardless which can be dangerous.
  5. The speed of the vehicle: the faster the speed the greater the braking capacity need. For double the speed, it is 4 times the capacity required.
  6. The road conditions: Uneven loose stones give less grip
  7. The weather, specifically if it has been or is raining: water can cause aquaplaning and brake fading
  8. The vehicle’s braking ability: How many pots and what size on the vehicle?
  9. The change in drawbar weight when the braking is applied; and the effect this has on the rear brakes of the vehicle: if the nose goes down because the caravan or camper trailer brakes are highly effective, there is more pressure on the rear of the vehicle for potentially a better result.

Given these factors, it is impossible for a braking component supplier to make a compliant statement with respect to the standard without a practical test. It is the caravan or camper trailer manufacturer that should do a practical test for the peace of mind of their users!

The test describes a precise way to calculate the braking deceleration of the combined vehicle and caravan or camper trailer. There is a standard of braking level of 3.8 metres per second per second that has to be complied with. Don’t be concerned with this number, we will give you practical meter distances in this article for you to compare with.

Before looking at some data, consider again the impact of your vehicle size.

At Kimberley we use a Hilux Diesel with a GVW of 1650kgs and a Toyota 200 Series with a GVW of 2650kgs. Both vehicles are at least 5 years old and fairly represent a “typical” tow vehicle in their class. Neither have been modified nor have non-standard braking systems. This gives a fair range of results and representation for users.

The results are in meters apply brakes with an off-road camper trailer or off-road caravan.

Distance to perfect stop in a straight line from 35km/hr to zero.   Vehicle and 1.2 tonne Kimberley Kamper power assisted Disc Brakes   Vehicle and 2.1 tonne Kimberley Kruiser S Class  power assisted Disc Brakes   Vehicle and 2.8 tonne Kimberley Kruiser T Class  power assisted Disc Brakes
 With Hilux Dualcab Ute  towing (Amarok Dual Cab Ute with T Class Kruiser) (1.65 tonne)  6.05m  5.7m  4.84m
 With Land Cruiser 200 Series
(2.65 tonne)
 5.55m  5.43m  4.59m

There are some interesting points here to note. The power assisted discs are very powerful brakes. Infact the stopping power is in excess of the independent report published by “AL-KO Sensabrake TM” for their own braking system (we calculate the deceleration from their report).
The Tandem axle braking is superior to the single axle caravan because the double braking capacity outstrips the additional weight.

The other interesting thing is the Heavier single axle Kruiser is less than the Kamper with the 200 Series. Why is this? The weight distribution on the Single axle S Class is just perfect for maximum braking. The wheels don’t lock and the brakes are right on the money. This is 220% of the requirements of the Australian Design Rules!

The results in meters of applying the brakes manually on the off-road caravan or camper trailer ONLY and stopping on just these brakes.

So the vehicle brakes are not used and this is a measure for emergency caravan braking.

STOPPING USING THE CARAVAN OR CAMPER TRAILER BRAKES ONLYDistance to perfect stop in a straight line from 35km/hr to zero.   Vehicle and 1.2 tonne Kimberley Kamper
power assisted Disc Brakes
  Vehicle and 2.1 tonne Kimberley Kruiser S Class
power assisted Disc Brakes
  Vehicle and 2.8 tonne Kimberley Kruiser T Class
power assisted Disc Brakes
 With Hilux Dualcab Ute  towing (Amarok Dual Cab Ute with T Class Kruiser) (1.65 tonne)  7.95m  20.02m  14.95m
 With Land Cruiser 200 Series
(2.65 tonne)
 10.95m  21.0m  16.54m

There are some interesting points here to note. The lighter combined vehicle mass with the caravan or camper trailer gives the best result. This is to be expected.

The Tandem axle braking is superior to the single axle caravan because the double braking capacity outstrips the additional weight.

These results are at 35 km/hr. If you are going much faster you need a much longer distance. But this data gives you a practical guide of the “parachute” effect of apply the caravan or camper trailer brakes ahead of the vehicle.