A new study conducted by HiQ Tyres & Autocare has found that suspension-related defects are now the leading cause of MOT failures across the UK. The study showed that suspension problems, often involving broken springs or leaking shock absorbers, were cited in nearly 40% of all failed tests.
The six-week study analysed MOT failure reports from a representative sample of HiQ Tyres & Autocare centres nationwide, uncovering a shift away from easily spotted issues such as worn tyres or faulty lights, towards hidden mechanical faults that often go unnoticed by drivers. Because suspension components are difficult for drivers to inspect and can degrade gradually over time, these faults frequently remain undetected until vehicles are examined on a ramp during their MOT.
Electrical and lighting faults, such as blown bulbs or faulty headlights, were the second most common reason for failure, appearing in 37% of reports, while tyre defects and braking issues were each recorded in roughly a quarter of reports. Steering faults featured in nearly one in four failure reports, further underscoring safety concerns around the overall condition of vehicles on Britain’s roads.
The findings also highlight broader changes in driving conditions that may be accelerating vehicle component wear. Poor road surfaces and potholes place additional strain on vehicles’ suspension and steering systems, while the growing presence of heavier vehicles on UK roads – including electric cars with longer service intervals – may be contributing to an increase in strain on structural components and deteriorating road conditions.
Craig Sprigmore, Retail Director UK & Ireland, HiQ Tyres & Autocare, said: “Many drivers expect MOT failures to come down to simple issues like tyres or lights, but what we are increasingly seeing are hidden mechanical faults that develop slowly and go unnoticed until inspection day. Suspension problems are a prime example: drivers may not feel any immediate change in the way the vehicle drives, yet these faults pose a serious safety risk.
“Heavier vehicles, particularly electric models, place more strain on suspension systems, and longer servicing intervals mean problems are less likely to be detected before MOT day. It is no surprise, then, that suspension faults are now the leading cause of MOT failures, particularly given that electric cars now account for more than 20% of the total new car market in the UK.”
The analysis builds on HiQ’s previous research into potholes and poor road conditions, which previously revealed that more than one in four tyre replacements in the UK are directly linked to the country’s deteriorating road conditions.
The MOT (Ministry of Transport) test is an annual check that ensures cars, light commercial vehicles and motorcycles over three years old in the UK meet road safety and environmental standards. Drivers pay up to £54.80 for a car MOT test (class 4 vehicle), so costs can escalate rapidly if vehicles fail and require work or replacement parts, particularly where maintenance has been delayed.
Common suspension defects recorded in the study included worn or damaged components, broken springs and leaking shock absorbers, all of which can impact vehicle stability, braking performance and handling. Lighting and electrical faults ranged from faulty lamps and indicators to misaligned headlights and other electrical malfunctions, while tyre and brake failures were frequently linked to worn tread, structural damage and deteriorating braking components.
Sprigmore concluded: “We’re dedicated to providing customers with the best possible care for their vehicles. We want to remind drivers that we offer free vehicle safety checks at our autocare centres nationwide. Regular vehicle maintenance is essential, and complacency is not an option when it comes to road safety. We strongly encourage drivers to keep up with routine car servicing and take advantage of free safety checks, which can help identify potential issues early and reduce the risk of MOT failure.”
