It is very important that the braketest gives a realistic picture of the dynamic behaviour of the car as when braking on the road. This can only be accomplished when testing with the car in movement

Brakedynamics are displayed for each wheel and the maximum brakeforce is shown in figures, including the handbrake. Retardation is calculated. Difference in brakeforce L/R and F/R is stated. With sideslip plate the side-slip is measured for front and rear wheels. Pedal force and brake force amplification is measured with an optional pedal force gauge.     Click on thumbnail to view the full picture.

The brakes are the most important safety equipment on a car. Therefore it is very important that the braketest gives a realistic picture of the dynamic behaviour of the car while braking on the road.
It should be remembered that the braking result is dependent not only on the brakes but also on the equipment “above” the wheels and the brakes, namely the suspension system, shock absorbers and the chassis, the weight of which parts are transferred to the road by means of the wheel struts, wheels and tires. Further-more modern cars are increasingly equipped with technical support systems designed to help the driver in critical and unforseen situations by damping or cor-recting any wrong decisions.
Most cars are fitted with limiter valves or proportional valves which control the distribution of the brakeforce between the front and rear wheels in order to avoid blocking of the rearwheels which may result in skidding. Nowadays an increasing number of cars are also fitted with ABS-systems and a number of vehicles are constructed with 4-wheel drive.
The mechanical construction of the wheel struts, suspension and steering gear in modern cars is complicated and designed to optimize the dynamic behaviour of the car under all driving conditions including braking. All these relations have to be taken into consideration when evaluating the safety of a car.
When the brake is activated in a moving car, the weight of the vehicle is propelled dynamically against the front axle causing the front brakes to be dominating. It is very important to register this dy-namic course of the brake force in order to conclude how the car brakes under realis-tic conditions.
The use of a modern plate-braketester which incorporates measuring of the dy-namic brake force and weight of each wheel is a natural consequence of this development. On a plate-braketester the braking ability of a car can be tested under completely realistic conditions as the test is made when the car is moving at a speed of 10-15 km/h. Through modern com-puter technology all forces are measured several thousand times pr. second thereby ensuring that all details in the dynamic flow are measured.
The measured results are displayed in colours on a big colour screen making it easy to observe the dynamic flow of brakeforce and suspension. On the OPTO-PLUS plate-braketester model 510 the dynamic brakeforces and the dynamic weight are shown for each wheel sepa-rately. Limiter- and proportional valves , ABS-systems and permanent 4-wheel drive systems are functioning realistically as on the road and can therefore be analysed for correct function.
Time used for such an analyzis is minimal and corresponds roughly to the time it takes to drive over the plates and brake the car. Therefore the plates can be installed in a driving lane in the work-shop, either flush-floor or simply mounted on top of an even floor.
Also in relation to the client who wants his car tested this form of test is excellent. Car owners today are increas-ingly aware of the safety aspects of their cars and want to know how they stand in respect to the condition of their vehicles. The plate-braketester is an instrument offering a quick analysis of a realistic test where the results are displayed in an easy comprehensible form in coloured graph-ics. Terms like steering gear, brakeforces, suspension etc. are easily understood as is the result of the test without it beeing necessary to use many explanations. For the workshop this is an excellent oppor-tunity to offer their customers a service product which increases their satisfac-tion and at the same time augments the image of the workshop.
Traditionally a roller-braketester is the most used type of brake tester whereas a plate-braketester like the OPTO-PLUS 510 is relatively new, its development having been made possible through ap-plication of modern PC-based systems with big computing power enabling the test results to be shown in graphic form and in colours.
A test on a roller-braketester can be understood as “the road turning “ under the wheels, while the car itself stands still. According to its nature this kind of test is static and in reality only the effect of the braking function is tested whereas the dynamic influence from weightdistribution, limiter-and pro-portional valves, suspension, wheels and tires are not taken into consideration.
Whether one or the other system is the better is dependent on the individual needs of the workshop and the required range of tests. Both systems have their advantages and deficiencies. Modern Plate Tester design has considerable advantages, making it very useful as a test instrument.
 
In the table below a comparison has been made between the 2 systems and their main characteristics. This picture shows the suspension dynamics for each wheel. At the same time a dampingfactor is calculated for each wheel as well as the L/R symmetry. Total weight and testspeed are indicated.