Brake Testers

How a Brake Tester Works

The vehicle moves onto the brake tester, and its wheels are put between the two big main rollers. The specifications about the vehicle are entered, and the rollers automatically start spinning at a certain speed. Following this, brakes are applied, applying force onto the motor.

While the vehicle is motionless while being tested by the rollers, its total braking force is determined by the brake tester mechanism. The vehicle’s braking efficiency is then calculated by the tester mechanism’s automated weighing system.

Types of Brake Testers

There are at most three types of brake testers used to determine the braking effort and efficiency of a motor vehicle:

Roller Brake Tester

This is a way of permitting the dynamic evaluation of a motor vehicle’s braking system while the motor vehicle itself remains stationary.

A roller brake tester consists of a mechanical floor unit that comprises electrical motors, double independent sets of three measuring rollers, braking force transducers, and extra safety sensors.

The driving rollers function at a low speed using a motor and gearbox setup. During a test, the maximum braking force is measured by applying the vehicle’s brakes, inducing a reactive force on the electric motor.

An electric transducer coupled with strain gauges then determines the induced individual forces that are acting on the deceleration stage in order to calculate the separate braking forces on each wheel.

Plater Brake Tester

This is a method of determining a vehicle braking system during a dynamic test. The unit comprises 2 moving parallel plates fixed on force transducers. Braking force measurement is done when a vehicle moves over the plates and applies its brakes.

This braking action results in individual plates ‘slipping’ forwards, enabling the calculation of braking force. Brake imbalance between the right and left hand sides can also be determined by the variances in voltage measured on each individual force transducer below the chassis.

Decelerometer

This is a handheld tool for measuring the dynamic braking forces during the course of a vehicle road test. A vehicle decelerometer functions as if it were an accelerometer, as it determines braking efficiency by utilizing those forces measured during a vehicle's deceleration.

A decelerometer is a straightforward process by which braking effort may be accessed swiftly and easily, but it is normally utilized as an indicator of tolerable brake performance.

Low efficiency readings mast lead to more investigation on either a roller brake tester or a plate brake tester.

Considerations When Choosing Brake Testers

The considerations when selecting brake testers include:

Method of Operation

• Roller brake testers measure the force reaction created by the brakes against a roller rotated by a motor, while a plate brake tester has strain gauges fixed to a plate held on bearings, and it measures the force needed to hold the plate while a vehicle brakes on top of it.
• Decelerometers are put in a vehicle and feature a pendulum which moves if a vehicle is braked.
• The amount of pendulum ‘swinging’ is determined to show deceleration during braking.

Brake Test Safety

• Roller brake testing is a moderately safe testing method, since the vehicle is static during the brake test. Instead, the rollers spin underneath the wheels.
• With both the decelerometer and the plate brake tester, testing requires that the vehicle be driven and braked on the plates, usually in the limited space of a roadside or vehicle workshop.
• This can be a danger to other workshops or road users.

Accuracy of Results

• Roller brake testers utilize the same braking surfaces when testing all wheels on all vehicles, guaranteeing accurate comparative tests.
• Plate brake testers utilize the same braking surface for all the wheels on every vehicle, while the decelerometers tests on road; therefore, the braking surface could differ from very good to very bad based on road condition.
• While a roller brake tester tests all vehicles at a constant speed, the plate brake testers and decelerometers tend to brake test at variable test speeds based on how a vehicle is driven.

Brake Test Adaptability

• Roller brake testers are able to test the complete range of every brake applied on a vehicle, from zero to maximum braking, or wheel lock constantly and repeatedly without influence of weight or momentum transfer.
• The decelerometers and plate brake testers cannot test the complete range of a vehicle’s brake successfully.
• Decelerometers cannot test separate axles, while plate brake testers are able to compare the brake balance across separate axles. Roller brake testers can consistently and repeatedly make a comparison of the brake balance across individual axles.

Advantages of Brake Testers

Below are some of the advantages of the individual testers:

• Being quite affordable and fairly portable, the decelerometer enables ease of use in many environments.
• Plate testers have less moving pieces and offer a more in-depth test, enabling weighing of vehicle axles.
• Roller brake testers can be set up for air pressure testing, bind (rolling resistance), and ovality (cracked or warped discs/drums).