Tyres with the wrong speed rating can affect the safety of the vehicle to which they are fitted. This is the word from Bridgestone which said that using a tyre at a higher speed that it is rated for could cause it to fail.
“Our national speed limit is 120km/h, but many cars are capable of 250km/h or more,” said Bridgestone’s General Manager for Field Engineering and Technical Services, Hiroshi Nakanishi. “Although we strongly discourage people from driving at unsafe or illegal speeds, we have no control over the way vehicles are used. For this reason, tyres must be able to cope with the car’s top speed.”
He commented that motorists were sometimes tempted to fit tyres with a lower speed rating to save money, but that this was false economy. “Fitting tyres with the wrong speed rating not only compromises safety, but may invalidate your insurance policy,” Nakanishi commented
He advised motorists to consult their vehicle’s owner’s manual to determine the required speed rating. “A car with a maximum speed of 190km/h would require a T-rated tyre. Fitting a tyre with a Q rating (160km/h) to such a car would be a safety hazard, because such a speed could be reached inadvertently, like on a downhill stretch,” he said.
TR – Speed Rating (Speed Symbol), Maximum Speed of 190km/h
QR – Speed Rating (Speed Symbol), Maximum Speed of 160km/h
Nakanishi said that a full list of tyre speed symbols was available on the Bridgestone website, www.bridgestone.co.za, to assist drivers in understanding the speed ratings of their tyres. “Consult a fitment centre if you are unsure about the correct speed rating for your vehicle’s tyres,” he concluded.