The eye-watering costs of failed MOTs
Having crunched the numbers we found there were a total of 20.2 million winter MOT tests across 2020 and 2021, with 1 in 5 (20%) vehicles failing their annual car safety test. With the cost of living crisis and the aftermath of Christmas, the last thing anyone needs during the winter months is yet another cost. However, our analysis reveals that with an average of 2 million failed MOTs each winter, and the most recent research putting the average cost of a failed test at £326.85, Brits will fork out a staggering £653.7 million for failed tests this winter.
The most common reasons to fail an MOT in the winter
To help shine a light on the areas of a car that drivers should prioritise looking after, our research has revealed the leading reasons cars fail their MOTs in the winter months. While it’s important to remember a vehicle can fail an MOT for multiple reasons, it’s clear that tyres, brakes and a car’s suspension should be carefully looked after if you want to avoid issues in your next test.
The 20 most common reasons cars fail an MOT in the winter:
Rank |
Reason for failure |
% of cars that fail an MOT for this reason |
1 |
Tread depth |
36.47% |
2 |
Tyre faults |
23.06% |
3 |
Brake discs |
20.61% |
4 |
Brake pads |
18.80% |
5 |
Coil spring |
16.42% |
6 |
Pins and brushes |
14.62% |
7 |
Registration plate lamp(s) |
12.29% |
8 |
Rigid brake pipes |
12.10% |
9 |
Service brake performance |
12.07% |
10 |
Non-component advisories |
11.65% |
11 |
Position lamp |
11.50% |
12 |
Headlamp aim |
10.65% |
13 |
Exhaust system |
10.63% |
14 |
Ball joint |
10.62% |
15 |
Headlamp |
10.35% |
16 |
Engine oil leaks |
10.06% |
17 |
Wipers |
9.70% |
18 |
Stop lamp |
9.00% |
19 |
Shock absorbers |
8.60% |
20 |
Joints |
8.27% |
Tread depth
The most common reason cars fail an MOT is because of a lack of tread depth – accounting for 36.47% of failures. Good tyre depth is essential for maintaining grip and allowing your car to brake successfully. A lack of tyre depth can heighten your chances of having an accident, especially in the wintertime when icy or wet roads already make braking more difficult.
The minimum legal requirement for tread depth in the UK is 1.6 millimetres, although we advise you to replace your tyres well before, at 3 millimetres; any less and your stopping distance when braking will start to increase. Testing your car’s tread depth is imperative not least if you’ve bought a used car. To do this, take a 20p coin and run it along the tread groove. If the outer band of the coin disappears you’re good to go, but if you can still see the outer band, it’s time to replace your tyres.
On top of keeping an eye on tread depth, you must also ensure your tyres are correctly inflated and that you limit heavy braking, acceleration and sharp steering.
Tyre faults
Several different issues fell under tyre faults, the second highest reason for MOT failures. Among them were seriously damaged tyres, visible or damaged tyre cords, a tyre not being fitted correctly and a tyre fouling another part of the vehicle.
Taking care of your tyres is pretty straightforward though. It is recommended that you change them every 20,000 miles or every 10 years (whichever comes first), and you should regularly check them for visible damage. Look out for cracks or cords which are a telltale sign you need to replace your tyre.
Brake discs and pads
Appearing at third and fourth were brake discs and pads. These essential components are vital to your car’s braking system and having issues with either or both could significantly affect your ability to stop.
In the winter, colder temperatures and excessive braking can overwhelm your braking system. To help reduce the risk of issues with your discs and pads we suggest keeping your car in a sheltered area, such as a garage if you have one. Try not to ‘ride on the brakes’ i.e. keeping your foot on the brake for long periods of time. Instead, select a higher gear to control speed and utilise your hand brake and engine braking when coming to a stop.
Coil springs
Part of your vehicle’s suspension, coil springs absorb the impact from potholes, bumps and rough terrain. The cold weather in winter can affect the steel in the springs making them brittle and more likely to break when impacted by harder, tougher and gritted roads. It’s therefore unsurprising to see them contribute to more than 1 in 7 (16.4%) cars failing their MOT across the winter months.
To help minimise damage to your coil springs, try to avoid potholes where possible and ensure you wash under your car to remove salt from gritted roads which can erode the springs.