A new study has revealed that suspension-related issues are now the single biggest cause of MOT failures in the UK, accounting for 38.1% of failed tests.
At first glance, that may seem surprising. Traditionally, many drivers assume the most common MOT failures involve simple issues like blown bulbs or worn tyres. But the research suggests something more concerning is happening beneath the surface.
Hidden mechanical faults are becoming increasingly common — and they often develop gradually, without obvious warning signs.
For fleets, that raises an important question – how many of these issues are developing unnoticed between inspections?
The Problem With “Invisible” Faults
Components such as springs, shock absorbers, and dampers gradually wear down through everyday use. Over time, potholes, poor road surfaces and heavy mileage can weaken these parts until they eventually fail an inspection.
The challenge is that many of these faults don’t dramatically change how a vehicle feels to drive, at least not immediately.
A leaking shock absorber or damaged spring can quietly reduce stability, braking performance and handling long before a driver notices anything is wrong.
This is why suspension defects are often discovered only at MOT stage — when the problem has already reached the point of failure.
The study also highlights another underlying issue… the condition of the UK’s road network.
Potholes and deteriorating road surfaces are placing increasing strain on vehicle suspension systems and steering components.
For vehicles covering significant mileage, especially vans or fleet cars travelling daily routes, that stress accumulates quickly.
This mirrors broader trends already emerging in fleet maintenance data. Rising wear rates across tyres, steering components and suspension systems are becoming more common as vehicles spend more time navigating damaged road surfaces.
The Wider Pattern in MOT Failures
Suspension faults may be the leading cause of failure, but they are far from the only issue fleets should be watching.
The same research found:
- Electrical and lighting faults appearing in 37.4% of failures
- Tyre defects affecting around one quarter of vehicles
- Brake issues also appearing in roughly a quarter of tests
- Steering faults showing up in nearly one in four failure reports
What these categories have in common is that many of them start as minor wear issues or advisories. If they aren’t addressed quickly, they eventually progress into full MOT failures.
This is something fleet operators will recognise from other industry data, where overlooked advisories often become more serious maintenance problems later on.
Why Fleets Should Treat This As a Warning Sign
For organisations running multiple vehicles, MOT failures are more than a compliance inconvenience.
They can lead to:
- Vehicle downtime
- Missed schedules or deliveries
- Unexpected repair costs
- Increased operational risk
More importantly, many suspension and steering defects directly affect vehicle stability and braking performance, which makes them a genuine road safety concern.
For drivers covering thousands of miles each year, even small mechanical issues can escalate quickly.
Fleets that rely solely on annual MOT tests to identify mechanical issues are increasingly likely to encounter preventable failures.
Instead, many operators are moving towards mid-year safety inspections, closer monitoring of driver-reported vehicle behaviour, tracking recurring advisory patterns and using fleet data to identify vehicles with repeated issues.
Catching suspension wear early not only prevents MOT failures but also reduces repair costs and keeps vehicles safely on the road.
At Driving Monitor, we understand the importance of vehicle health to keep you moving, which is why Telematics Monitor and Fleet Monitor are an integral part of our offering.
