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Time to fix re-torqueing confusion
Page 30
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I WAS INTERESTED to read the letter from Alan Everett raising the issue of wheel torque (CM 14 June).The British Tyre Manufacturers' Association (BTMA) is very much aware not only of the apparent failure in the market to adhere to wheel torque settings but also of the unclear situation regarding re-torqueing procedures.
Recent reports of loose wheels and in some cases wheel loss give cause for concern, and an investigation by BTMA has highlighted exactly the issue Mr Everett raises, whereby correct wheel torque settings are either unknown or are not being adhered to. Either way, this is a serious issue.
What is equally alarming is a discrepancy in the wheelnut/stud re-torqueing procedure. Tyre fitting/servicing companies commonly adopt a 30-minute waiting period for the re-torqueing of nuts/studs after a wheel has been put back on a vehicle. Many of the vehicle manufacturers, however, do not recognise a time-based waiting period but instead stipulate a distance-based one, typically 50-80km.
The time-based process has been a long-standing practice within the tyre fitting/servicing industry and our research suggests this is so because of practical difficulties in adhering to a distance-based process. For example, if a wheel is replaced on the roadside, it may not be practicable for the tyre fitter to follow the vehicle for 50km, and the vehicle driver may not have the equipment to carry out the procedure himself.
Additionally, there appears to be a level of ignorance regarding over-tightening of the nuts/studs. Some fitters/mechanics seem to believe tightening above the recommended torque adds to vehicle safety.This is not so and it has been known for this practice to lead to distortion and excessive wear of the wheel stud holes and wheel fixing components, leading to loose wheels and wheel loss.
Despite not being directly tyre related, this is one of most frequent issues to arise following a tyre replacement and hence BTMA has taken the initiative in calling for discussion both across the industry and with the government to identify a workable code of practice for the benefit of all.
AJ Borten Chief Executive British Tyre Manufacturers' Association