An investigation of nearly 500 secondhand cars for sale in the UK found 16% are being sold with ‘potentially dangerous’ tyres
A new probe into secondhand car sales has revealed that around one in six motors (16%) on sale in the UK are equipped with ‘potentially dangerous’ tyres that may not survive until their next MOT. The study also discovered that around 8% of vehicles are being flogged with tyres that would earn a ‘warning’ for their condition during an MOT, and many are being sold at or below the legal tread limit of 1.6mm – shockingly, even from dealerships.
The research, commissioned by Halfords and conducted in partnership with Professor Peter Wells, director of the Centre for Automotive Research at Cardiff University, scrutinised nearly 500 cars up for sale in over 100 locations across the UK. The findings, unveiled during Tyre Safety Month, showed that about one in six vehicles (16%) were being sold with a mere 3.6mm of tyre tread or less.
This amount was deemed ‘potentially dangerous’ by Professor Wells, as cars typically burn through 2mm of tread over the course of a year – the next time many will receive an MOT and have their tyres inspected. Tyre performance also starts to go downhill at this stage. New tyres usually come with 8mm of tread.
Many vehicles were found to be in an even worse state. About one in 12 (8%) had a paltry 3mm of tread or less – the level which would result in cars receiving a ‘warning’ at an MOT if tested in the condition they were being sold.
This is also the point where performance noticeably worsens – by approximately 20% in wet conditions – meaning they are strongly advised to be replaced. Out of the 481 vehicles studied, four were found to have tyres with a tread of 1.6mm or less. Three of these had over 10 months remaining on their MOT, indicating they would likely be illegal by that time.
Although technically within the law, tyres with a tread of 1.6mm are significantly compromised – it would take them 171 metres to stop a vehicle travelling at 70mph in wet conditions, compared to just 94 metres for a vehicle with new tyres. This could be the difference between stopping safely and crashing at 46mph.
One car, valued at £8,000, was available for sale from a dealership with visibly worn tyres with a tread of 1.55mm and a ten-month MOT. In another instance, a major brand dealership was offering a £15,000 car with a 12-month MOT and tyres with just 1.6mm of tread.
Both cars were available for test drives. At present, secondhand cars can legally be sold with a 12-month MOT and a tyre tread of just 1.6mm – the minimum legal limit. However, just 0.01mm of additional wear would make them illegal.
This could occur after approximately 33 miles, meaning the vehicle could be illegal by the time the new owner drives it home. Data from Halfords reveals that in the past year, more than 6,000 vehicles brought in for servicing were found to have less than 1.6mm of tread, making them illegal. An additional 16,500 had between 1.6mm and 2mm of tread.
Adam Pay, the managing director of Halfords Garages, has criticised current regulations regarding tyre tread depth on cars sold: ” The current rules for tread depth on cars sold do not put motorists’ safety first. Most motorists do not check tyres between MOTs and expect a car they have bought will be safe until its next MOT. The fact it is legal to sell a car with a 12-month MOT that, in a matter of miles or days will be illegal, at best lacks common sense and at worse could cost lives. The law needs an urgent rethink.”
Professor Wells, who collaborated with Halfords on the research methodology and data analysis, described the findings as “extremely worrying” and “an accident waiting to happen”. He estimated that around 1.2 million cars are being sold each year with potentially dangerous tyres, while over 75,000 are likely sold with illegal ones.
He warned: “Tyres are one of, if not the most safety-critical aspect of a vehicle. Once they approach 3mm, their braking and roadholding ability has already begun deteriorating noticeably and it only gets worse from there.
“The difference in stopping distance between new tyres and ones with 1.6mm of tread is 75 metres if travelling at 70mph in wet conditions. That’s the difference between stopping in time, or crashing at 46mph. There is a question of whether 1.6mm should be road-legal at all.”
Backing Mr Pay’s call for higher limits, Professor Wells said: “I would propose that imposing a legal limit of 3.6mm, or even 4mm, would be sensible.”
A recent consumer survey among drivers revealed that the majority of Brits were in agreement. More than eight out of 10 (81%) reckon it should be a legal requirement for all secondhand cars sold in the UK to have sufficient tyre tread to last until their next MOT.
The study also revealed that more than half (53%) of those who bought a used car in the past year had to replace a tyre on the vehicle. When asked how they would feel if they purchased a secondhand vehicle with less than 3mm of tread, 40% said they would feel ‘let down’ and 35% felt as though they were being ‘put in danger’.
TyreSafe – the UK’s charity dedicated to promoting tyre safety, which also organises Tyre Safety month every October – has welcomed the research findings to raise awareness of the issue.
Stuart Lovatt, chairperson of TyreSafe, said: “This is the most detailed study we have seen into the state of tyres on vehicles being offered for sale in the UK and suggests that huge numbers are being sold with sub-standard tyres. Our aim is to reduce tyre-related incidents on Britain’s roads and this research highlights how careful consumers have to be when buying a car and the importance of taking personal responsibility for checking your tyres are safe.”
Halfords is offering free tyre checks across the country to assist drivers who have recently bought a second-hand car and want to ensure their tyres are up to scratch. This includes the 10-Point Check, which is free for Halfords Motoring Club members, as well as the Free Tyre Check and a variety of tyre tread gauges that drivers can use to check their own tyres. More information about tyre safety can be found at halfords.com/tyre-safety.html
Motorvise conducted the tread depth testing, inspecting the tyres of 481 vehicles for sale at more than 100 dealerships throughout the UK. Several cars being sold privately were also included in the checks.
The methodology and data analysis of the survey was overseen by Professor Peter Wells. The research relating to drivers was carried out by OnePoll between September 30 and October 2, 2025, among 2,000 UK motorists.
A Department for Transport spokesperson said: “Selling dangerous vehicles that are not up to standards is illegal and private sellers found fraudulently selling cars with unsafe tyres should be held accountable. We take road safety seriously and urge all drivers to ensure their vehicles are safe and legal before taking them on the roads.”
The DfT added that the DVSA’s market surveillance team worked closely with local Trading Standards teams to carry out checks on garages selling part-worn tyres, who can face prosecution if they break the law. The DVSA’s Market Surveillance Unit ensures vehicles and components sold in the UK comply with their legislative requirements by conducting physical testing and documentation inspections.
Any retailer selling part-worn tyres which fail to meet these requirements is breaking the law under the Consumer Protection Act 1987 and could be subject to a substantial fine or prison sentence and misrepresenting the condition of a vehicle during sale, including tyre safety, is considered fraudulent.
It also said that tyres were safety-critical components and were checked as part of the MOT test, ensuring tyres have adequate tread depth and are free from cuts or bulges. Any vehicle with defective tyres will fail an MOT test and is not permitted to be driven on the road.
The DfT said that vehicle owners were responsible for always maintaining their vehicles in a roadworthy condition, not just for the time of an MOT test. It also recommends that drivers regularly monitor tyre tread depth and replace tyres well before they reach the legal minimum of 1.6mm.