Nearly four in ten MOT failures across the UK are now linked to suspension defects — faults that most drivers have no way of spotting themselves, according to new research from HiQ Tyres & Autocare.
The six-week study, which analysed MOT failure reports from a representative sample of HiQ centres nationwide, found that suspension problems were cited in close to 40% of all failed tests, making them the single most common reason for MOT failure. The findings represent a notable shift away from the visible, easily checked issues that traditionally drove failure rates, pointing instead to hidden mechanical faults that develop gradually and often go undetected until a vehicle is examined on a ramp.
Broken springs and leaking shock absorbers were among the most frequently recorded suspension defects, both of which can affect vehicle stability, braking performance and overall handling without producing obvious symptoms for the driver.
Electrical and lighting faults ranked second, appearing in 37% of failure reports. These included blown bulbs, faulty headlights and misaligned lamps. Tyre defects and braking failures each featured in roughly a quarter of reports, while steering faults appeared in nearly one in four cases, a spread of results that HiQ says underscores broader concerns about vehicle condition on Britain's roads.
Craig Sprigmore, Retail Director UK and Ireland at 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."
The research highlights a broader set of pressures on vehicle components. Poor road surfaces and potholes place additional strain on suspension and steering systems, while the growing weight of vehicles on UK roads (notably electric cars, which are heavier than their combustion-engine equivalents) may be contributing to faster component degradation.
Longer service intervals on modern vehicles compound the problem further, reducing the frequency with which faults are likely to be caught before MOT day arrives.
Sprigmore noted: "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 study builds on previous HiQ research into road conditions, which found that more than one in four tyre replacements in the UK are directly linked to the country's deteriorating road surfaces, a figure that sits alongside RAC data recording a 17% increase in pothole-related suspension incidents during the final quarter of 2024 alone.
The MOT test — the Ministry of Transport's annual roadworthiness check for cars, light commercial vehicles and motorcycles over three years old — costs drivers up to £54.80 for a standard Class 4 vehicle. When suspension or other mechanical faults require remedial work, the overall cost can escalate rapidly, particularly where maintenance has been deferred.
Sprigmore urged drivers not to wait for the annual test to identify problems: "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."
HiQ operates a network of more than 190 autocare centres across the UK and offers its HiQ2U mobile service for customers who require tyre replacements, brake checks and other services at home or at the roadside.
Source: HiQ Tyres and Autocare Road Safety Survey 2025. SMMT new car registration data cited for EV market share figures.
Tagged with: MOT failure causes, suspension defects, vehicle safety checks, HiQ Tyres Autocare, pothole damage, EV tyre wear, shock absorber failure, broken springs, MOT test UK, free safety check, road surface deterioration, tyre retail UK
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