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Chicago Pneumatic highlights importance of correct tightening specifications


Tyre changing on any type of vehicle is a regular job for mechanics and it can seem quite straight forward. As such, operators can tend to overlook the tightening specifications recommended by the vehicle manufacturers. This practice should be avoided however, as it can lead to downtime and serious safety consequences.

Workshop equipment manufacturers, Chicago Pneumatic has highlighted three important steps to follow to ensure the right level of torque is provided when tightening.

Be aware of the manufacturers’ specifications and refer to them
Manufacturers always provide recommendations for each tightening job, and these can be found in the specifications book, or maintenance manual, which is more commonly called ‘blue book’. Before you start tightening you should double check the book to ensure your job is performed to the best standard.

With new innovations in materials and tools, it’s important to keep your knowledge current and follow the latest specifications. For example, nowadays most wheel rims are made from aluminum instead of steel but this does not mean that aluminum rims are harder and more torque is needed. The rim material affects the torque that should be applied. Continuous training is highly recommended and this can be offered by different providers.

Surface preparation is key
A substantial amount of torque is “lost” or wasted by friction during tightening. Chicago Pneumatic advises preparing the surface properly by cleaning all the elements to eliminate any rust, dust and dirt. Once you finish cleaning and before you start tightening inspect all components: wheel, studs and long nuts.

“Clamping force can be affected by other factors: parts quality, airline set up and tools maintenance or calibration,” said Christophe Roland, Very High Load Specialist at Chicago Pneumatic.

Prevent over-tightening
Wheel nuts that are over-tightened can often become damaged or broken, especially when hitting bumps in the road. This can result in a potentially catastrophic failure of the wheel, posing a serious risk to the safety of the heavy vehicle and its drivers. It’s important to use the right combination of tools to prevent this and achieve the right level of torque.

Roland added: “If you spot any signs of deformation or stretch on a stud, there is a high probability that tightening is above manufacturers specifications. Therefore, it’s key to replace the stud as soon as possible, and review your tightening processes. ”