3 Types of Brake Testers
Purchasing a car is one of our more serious decisions ranking as one of our largest investments after a house or business. Though appearance can be important, our main concern is affordability and dependability. Depending on the buyer, one or all of these factors are considered since they are central to the final decision. For most people, dependability is number one followed rather rapidly by affordability. Everyone wants to have the best possible mode of transportation with as few hassles as possible. It would be nice if it looked great, but that tends to fall at the end since sharp-looking vehicles are very expensive.
When the final decision is made, there is a sense of triumph and joy realizing we have something new in our life that will get us from point A to Point B with little trouble or inconvenience. Though few of us have mechanical ability, we judge the quality of the engine by the sound that it makes listening for any inconsistencies or unrecognizable sounds. If it sounds good, it is assumed it runs well.
A strange and unusual aspect of car purchasing is ignoring its most important part – the brakes. For some reason, it is taken for granted that the brakes have been tested and approved. Very few car buyers ever ask about the quality of the brakes or when they were last tested, a safety feature that should be at the top of everyone’s list.
Experts recommend that brakes should be tested and checked three times every year. Though road tests are commonly used, they are the least likely to identify any problems. There are three preferred tests recommended by mechanics. Unlike a road test, instruments are placed on the brakes to determine efficiency, performance, and wear.
It is important to understand that brakes, especially on modern high-performance vehicles, are crucial to optimal vehicle performance. To emphasize this point, imagine that you are driving down the highway at 70 miles an hour. If you have fully operational brakes and need to stop suddenly, it will take over 400 feet before your car comes to a complete stop. For this reason, it is important to have one of the three following tests performed yearly on your car.
Roller Brake Tester
Roller brake testers use a floor-mounted set of rollers to measure brake force. Two wheels of the vehicle are mounted on to each of the rollers, which are covered with a plastic material that provides friction. A third roller, located by each of the primary rollers, detects the presence of the vehicle and whether there is tire slippage. The wheels are turned at a constant speed over the rollers as the vehicle sets motionless. Measurement is calculated by the torque force produced by the deceleration of the wheels against the rollers, which operate at low speed to avoid stress on the wheels or vehicle. This type of test does not require the operator to be in the vehicle and is done remotely. A special feature of this test is the measurement of the brakes on each wheel to see they are working in unison. The tester accurately measures time lag, which can help avoid “jack knifing” when the brakes are applied. It also measures prime movers that maximize the balance and efficiency of the vehicle.
The plate tester is somewhat similar to the roller brake test. As with the roller version, two parallel plates are installed in the ground and mounted on a force transducer that measures force, weight, and pressure. The data collected by the transducer is sent to a computer. Force inducers are perfectly suited for computers since they produce either analog or digital data and come in several sizes. As the wheels cross the skid plates, the brakes are applied to cause the plates to slip producing a calculation of braking force. The operator of the vehicle must approach the plates at a constant speed and be aligned with the plates. The brakes are applied at precisely the moment the wheels hit the plates to ensure the accuracy of the test. In many cases, the process has to be repeated a couple of times to guarantee a proper reading.
The decelerometer test is a road test where a devise is strapped to the passenger seat of the vehicle. The equipment measures inertial force as the vehicle decelerates. The speed of the vehicle is predetermined prior to beginning the test and must be constant for it to be accurate. Regardless of brand of decelerometer being used, the g-force principle or gravitational force equivalent, the reaction of one force against another, is used to measure the efficiency of the brakes. Since this method of brake testing is inexpensive, it is used to test new cars and high performance ones. Unlike the other tests, it does not provide data on the effectiveness of the individual wheels or whether there is damage to the brakes.
It is interesting that we take for granted a mechanism that is so important to our safety. What is really astounding is how easy it is to get brakes tested with a minimum of expense or time. The next time you are flying down the highway at 70 or 80 miles an hour, think about what you have to rely on to save your life when everything in front of you stops. These three methods of evaluation could be the key to whether you walk away or not.