Birmingham City Council trading standards officers carried out a series of inspections of part-worn tyres being sold in the city and found that nine out of ten failed to meet the minimum legal standards.
Among the failures were tyres which had nails embedded, illegal tread depth, exposed cords, inadequate markings and one tyre which was 17 years old.
The investigation comes just weeks after TyreSafe found that more than one in ten drivers is more likely to buy part worn tyres compared with 12 months ago.
“The results from the Birmingham investigation are extremely worrying and confirm our worst fears about part worn tyres,” explains Stuart Jackson, chairman, TyreSafe.
“Although guidelines do exist about the condition of tyres being sold as part worns, they are clearly not being adhered to by all traders.
"The types of faults found are extremely dangerous and if fitted to a vehicle, could have caused serious accident and injury.
"We would always recommend fitting brand new tyres.”
This year was Council's ninth annual investigation and saw it buy 10 tyres from retailers across the city.
Over the course of the entire programme, the team bought and tested more than 190 part worn tyres with 25% found to have some form of structural defect. In this year’s survey 30% of tyres had structural failings including illegal tread depth and a nail embedded in the casing while 90% did not have the correct markings required by law, which identify them as a part worn tyre.
To validate the hidden dangers of part worn tyres, TyreSafe examined six of the tyres bought by Birmingham Trading Standards by x-ray to identify any further internal damage. All of the tyres showed signs of impact damage resulting in unstable stress points or fatigue in components which would make them much more likely to suffer a blowout.
These highly dangerous defects would not be visible under normal inspections that part worn tyres must undergo before going on sale.
As such a safety critical component, many regulations govern the sale of part worn tyres. Among them tyres must be permanently marked as part worn, they must have at least 2mm of tread depth around the whole tyre and the original grooves must be clearly visible in their entirety. Any repairs to the tyre must have been carried out in accordance with British Standards BS AU 159.