Roller Brake Testers
If you’re involved in the automotive industry in any way and particularly if you run an MOT Bay, then you know how important it is to ensure that vehicles are operating safely and efficiently. One crucial aspect of vehicle maintenance is the brakes, which are responsible for slowing down and stopping the vehicle.
That’s where the Roller Brake Testers (often known as MOT Brake Testers) come in. These machines are designed to accurately test the effectiveness of a vehicle’s brakes, allowing mechanics and technicians to identify any problems or issues that need to be addressed. In this article, we’ll take a closer look at Roller Brake Testers, including how they work, the benefits they provide, and some common questions and concerns about their use. So whether you’re a seasoned mechanic or just learning about these devices, we hope you find this article informative and helpful.
What is a Roller Brake Tester?
Roller brake testers are specialised devices used to test the braking performance of vehicles. These devices use a series of rollers that the vehicle’s wheels pass over, allowing the tester to measure the braking force applied by the vehicle and determine if it meets safety standards.
Roller brake testers, also known as brake tester machines are valuable tools for ensuring the safety of vehicles on the road. By accurately measuring the braking performance of a vehicle, they can help identify potential problems and ensure that the vehicle is operating at its best.
Anyone who owns or operates a vehicle should have its brakes tested regularly to ensure that they are functioning properly and that you are driving a safe and reliable vehicle.
The advantages of roller brake testers
A key advantage of roller brake testers is their ability to test the braking performance of a wide range of vehicles, from small cars, vans and light commercial vehicles, to larger trucks and buses. The smaller Class 1 roller brake testers are also widely used for motorcycle brake testing. Hence why roller brake testers tend to be the most widely used brake testing systems used in MOT testing centres and are often placed just in front of the 4 post MOT ATL lift ready to be used for the rest of the MOT test.
The disadvantages of roller brake testers
As well as a roller brake tester needing a 3 phase (415v) power supply to power the heavy rollers, the other consideration when looking at the alternative brake testers is that the roller brake tester is very heavy, and sits in a cartridge unit that needs to be embedded into the ground, such that it sits at floor level within the garage or MOT Bay, and so as part of the installation the floor needs to be cut out and concreted to make a suitable area for the RBT to be placed and securely fastened into before it can be operated, hence the cost of the civil works and potentially the electrical upgrades must be factored into the purchase price of the roller brake tester
What are the 3 types of Brake Tester?
There are three main types of roller brake testers:
- roller brake testers
- plate brake testers
Plate brake testers are less popular but can be used for vehicles with permanent 4-wheel-drive systems, and consist of a moveable plate on each of 2 platforms, that the vehicle is driven onto, and then the braking motion allows the plates to move slightly to record the stopping ability of each of the vehicle wheels.
Roller brake testers are embedded into the ground such that they sit at the same level as the floor, they are equipped with rollers that rotate as the vehicle wheels are rotated on them, allowing for a more realistic simulation of driving and braking conditions.
Deceleromters are handheld electronic devices that can be taken in a vehicle during a test drive and brake test, and they will test the braking efficiency by calculating the rate of deceleration. This should be used where a plate brake tester or roller brake tester is unavailable or unsuitable.
What is a Roller Brake Tester?
A Roller Brake Tester, or RBT, is a device used for testing the condition of a vehicle’s brakes. It measures the force required to stop a vehicle’s wheels when travelling from speed. This data gives technicians an indication of how well the brakes are performing. RBTs are highly accurate and provide technicians with a reliable assessment of the brakes’ condition, and whether further investigation into the braking system is necessary.
The RBT allows for a dynamic assessment of the braking system of a motor vehicle as if it were being used on a road, whilst the vehicle itself is in a relatively static condition. This type of brake tester is typically used in UK garages as part of an MOT/ATL inspection lane for the MOT test, as passing the brake test is part of the annual MOT test for vehicles in the UK.
How are brakes tested on an MOT?
Initially after checking the use of the brake pedal for wear or excessive play, a visual inspection of the brake pads, brake disks and braking system, looking for visible wear or leakages must be done.
Next, the efficiency and braking balance will be checked on a roller brake tester (RBT). In certain cases where a roller brake tester may not be used (for example on certain 4-wheel drive vehicles), it may be necessary to perform brake efficiency and balance on a manual road test, with a portable brake testing device called a decelerometer.
The braking performance numbers must be reported to DVSA as part of the MOT test, and if the RBT or decelerometer are connected MOT equipment, this data would automatically be sent to the MOT Testing System (MTS) and will be recorded against the MOT currently being performed.
How does a roller brake tester work?
Roller brake testers work by way of two sets of two large ceramic rollers (4 large rollers in total) linked to a computer running the RBT software. The wheels from one axle (front or rear) are driven to be positioned between the rollers and the rollers spin, these produce friction between the rollers and the vehicle tyres. As the brakes are applied the friction force increases and this figure will be collected by the roller brake tester system to assess the forces applied at each wheel.
The roller brake tester also has weighing cells on each side of the unit with a further safety roller that can detect when a vehicle is present – this monitors both the arrival of the vehicle into the RBT as well as any tyre slippage.
How do you use a roller brake tester?
A roller brake tester works by the vehicle being driven onto the set of rollers (it’s not important which axle is tested first) ensuring that the wheels are centrally located to the 2 sets of rollers.
With the vehicle stationary, the rollers are started in a forward direction and accelerate up to a constant speed of around 3mph, during this acceleration process any minor inconsistencies in the wheel alignment within the rollers will correct themselves.
As the wheels are rolling, the brakes are applied gradually and the readings for each are recorded by the RBT, to assess if the braking effort for one wheel is significantly better or worse than the other, as well as ensure that the overall stopping ability is suitable to pass the MOT test.
The brakes may be applied and released several times during the test to ensure no binding upon release as well as to ensure that the braking ability and force remain consistent each time the brakes are applied.
To use a roller brake tester, the vehicle is driven over the rollers at a specific speed, and the tester measures the braking force applied by the vehicle’s brakes. This information is then used to calculate the braking efficiency of the vehicle and determine if it meets the necessary safety standards.
Truck roller brake testers work by having a truck drive onto a set of ceramic-coated rollers, which produce friction. These are linked up to the testing system, and the brakes can be tested by keeping the vehicle static while turning the wheels at a consistent speed.
If there is a parking brake on the axle you are testing, you would test that next, but if there isn’t, move the vehicle to test the next axle.
The service brake test for the front wheels and rear wheels uses the same procedure and Reasons for Rejection (RfR), so the instructions apply to both axles
If the vehicle or system cannot be tested on a roller brake tester, set up the decelerometer in the vehicle in accordance with the equipment manufacturer’s instructions.
Can you fail MOT for brakes?
Yes, there are a range of tests that need to be carried out and can fail the MOT, these include:
- Brake condition and operation
- Service brake performance and efficiency
- Secondary brake performance and efficiency
- Parking brake performance and efficiency
- Additional braking device (retarder) performance
- Anti-lock braking system (ABS)
- Electronic braking system (EBS)
- Brake fluid
For full details see the latest guidance on the DVSA website:
At what speed is the brake test carried out?
Speed using a Roller Brake Tester (RBT):
Standard Class 4 or Class 7 brake tester rollers usually spin at between 2.5 and 5km per hour or around 3 miles per hour
Note: The roller brake tester sets the speed of the test as the rollers themselves are spinning and the vehicle is simply braking
Speed using a plate brake tester:
For each brake check, the mechanic must drive the vehicle forwards at a steady speed of about 4mph up to the plate tester.
Speed using a decelerometer
Drive the vehicle on a level road at a steady speed of approximately 20mph (32kph) and progressively apply the service brake to maximum
What is the minimum brake performance for MOT?
If braking effort from any wheel of the vehicle is less than 70% of the maximum effort recorded from the other wheel on the same axle, or in the case of testing on the road, if the vehicle deviates excessively from a straight line, then this is a major MOT Failure.
If the braking effort from any wheel is less than 50% of the maximum effort recorded from the other wheel on a steered axle then this is deemed dangerous.
For full up-to-date MOT brake guidance from DVLA see:https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/1-brakes
What is the minimum brake efficiency for MOT?
For passenger cars the minimum service brake efficiency is 50 per cent (58 per cent for cars first used on or after 1 September 2010) And for the parking brake (hand brake) efficiency must be 50% of the required value to prevent this being deemed dangerous.
For full upto date MOT brake guidance from DVLA see:
Are brake pads checked as part of an MOT test?
Yes, the brake pads are checked as part of the annual MOT test, as well as the brake linings, fluids, braking efficiency and the entire braking system. As this is the only means of efficiently stopping a vehicle at speed it is one of the most important MOT tests to be completed.
What is the brake pad limit for MOT?
For MOT if a brake pad is worn down to the wear indicator or if the Brake lining or pad is contaminated with oil, grease etc, then this is a major MOT failure. If the pad is below 1.5mm, or the pad is missing or incorrectly mounted this is deemed as dangerous.
What is the calibration interval of the roller brake tester?
Roller brake testers (RBT), plate brake testers, ATL and motorcycle weighing facilities, and headlamp beam testers.
RBTs, PBTs, ATL and motorcycle weighing facilities, and headlamp beam testers can be calibrated anytime during the six months following their last date of calibration.
For the latest DVSA guidance see:
Help with your roller brake tester
If you are considering or even in the process of purchasing or setting up a roller brake tester (RBT), or indeed any other type of garage equipment either stand-alone or as part of an MOT Bay build and need some information, helpful free advice or additional garage or MOT equipment give Concept Garage Equipment a call, we would love to help you get your garage equipment set up and paying for itself as soon as possible.
We can offer you advice over the phone at 0113 469 0572, we sell roller brake testers online and over the phone, including delivery, installation and staff training in the correct use of the brake testing equipment or any other garage equipment up to a full MOT Bay.
Call us today on 0113 469 0572 or use the website contact form today, we are here to help.
Note: All information is accurate at the time of writing, November 2022.