Every vehicle workshop needs some kind of brake testing equipment. But not all brake testing systems are created equal.
If you’re serious about brake testing — or you’re looking ahead to MOTs — you need to understand your options (and what the DVSA recommends).
Here’s what you need to know about the three most common types of brake testing equipment:
Decelerometers
Good for:
- Vehicles where a roller brake test isn’t possible
- A backup test if your main brake tester isn’t working
- Quick ‘field tests’ on smaller vehicles
A decelerometer is the most basic type of brake testing equipment. And in most cases, it’s the least desirable (and least eligible) way of testing brakes. Especially in the eyes of the DVSA, who only allow decelerometers in specific circumstances — or as a ‘last resort’.
A decelerometer works by measuring the slowing of the vehicle itself: its actual deceleration. That means a brake test involves real driving and real braking.
But despite this ‘real-world’ braking, it doesn’t give the most accurate or detailed results. It’s a measure of the deceleration of the vehicle as a whole, which means you’re missing out on:
- Braking results for each axle separately
- Any imbalance between the left and right sides
- Controlled and repeatable testing conditions.
Because of the limitations of decelerometers, it’s rarely recommended by the DVSA. But there are some situations where a decelerometer might be necessary, such as:
- Vehicles with a weight that’s too high for a brake tester
- Vehicles with an unusual shape or design — that won’t fit a brake tester
- Some hybrid or EVs with a parking brake that can’t be disengaged for a static brake test.
So for commercial vehicle workshops that are serious about brake testing (and especially if they’re planning for MOTs), a decelerometer won’t be enough as your main type of brake testing equipment.
Roller brake testers
Good for:
- In-depth analysis (each axle, each side)
- Consistent and repeatable conditions
- Accurate and reliable MOT results
There’s a reason why the DVSA recommends roller brake testers as the gold standard for brake testing systems:
They’re the most accurate and reliable — with the most consistent and repeatable test conditions.
Unlike a decelerometer, a roller brake tester doesn’t measure a vehicle’s braking as it moves. Instead, it simulates movement by turning the wheels while the vehicle is in a static position.
That means you can repeat multiple tests without worrying about variations in:
- Driver behaviour
- The speed of the vehicle
- Dirt or moisture on the road or tyres.
On top of that, you can also get specific data on different parts of the vehicle — testing each axle or wheel separately, as well as testing your parking or emergency brakes.
Compared to a decelerometer (which are usually portable and low-cost), a roller brake tester does come with more of a commitment:
It’s often a more costly investment, and the installation of an in-ground brake tester will come with some structural work (as opposed to a mobile brake tester, which doesn’t need the same level of installation).
But for any workshop that needs a high level of accuracy and specific data in its brake testing, a roller brake tester is almost always the best choice.
Plate brake testers
Good for:
- Faster routine checks
- Lower maintenance and repair needs
- More portable than an in-ground brake tester
Plate brake testers sit somewhere in between a decelerometer and a roller brake tester.
By driving a short distance (at a slow speed) over the length of the plate brake tester’s surface, the tester uses pressure-sensitive plates to measure the forces from each wheel as the vehicle brakes.
Like a decelerometer, the test involves a moving vehicle, and measures the real-world action of a driver braking over a short distance.
But like a roller brake tester, you’re measuring more than just the total deceleration of the vehicle. A plate brake tester can also give you accurate data about separate wheels and sides of the vehicle.
That makes a plate brake tester much more accurate than a basic decelerometer. But in most cases, it won’t be as good as a roller brake tester. Because a plate brake tester works with a moving vehicle, the test results are vulnerable to inconsistent conditions — like moisture or dirt on the surface or the tyres.
It does, however, come with fewer moving parts than a roller brake tester, which can mean fewer repairs and simpler maintenance in the long run.
Still not sure?
If you’re expanding your workshop (or just looking at upgrades), we’re here to help.
We’ve worked with countless heavy-duty workshops to help them assess and decide on the best types of equipment for what they need — with a team of workshop experts on hand to talk you through your options.
You can see our full range of brake testers in our online shop — or start a chat with one of the team and tell us what you’re looking for.
This article was originally published by Totalkare.
