Corrosion of steel belts in older tyres was evident that may compromise strength and cause failure
A report produced by the Transport Research Laboratory (TRL) has shown that the age of a tyre can influence its structural integrity, lending weight to the government’s plans to ban the use of tyres over 10 years of age from coaches, buses and minibuses.
The research project was commissioned largely based on the efforts of the Tyred campaign. It was launched after a coach crash on the A3 in 2012 that claimed three lives after the failure of a drive axle tyre.
As part of the TRL study, 31 tyres were subjected to laboratory testing. All were of size 295/80 R22.5, had not been re-treaded and were aged between three and 19 years.
Each one that was aged eight years or above exhibited corrosion in one or more of the steel belts, with it being most prevalent in the uppermost belt in the tyre’s structure.
“This is important to consider, as loss of integrity as [that belt] can be associated with the separation of the tread and deflation of the tyre,” says the report.
The government has already issued advice that tyres aged 10 years or older should only be used on a drive axle. At that time that the consultation commenced, it had not been able to identify any research that supported the argument that a tyre is liable to fail based purely on its age.
In November 2018, DVSA declared that the discovery of a tyre that is more than 10 years old fitted to a coach or a bus would likely trigger a follow-up investigation of the operator, and possible referral to the Traffic Commissioner.
