Are you using the right level of torque for a job? Tool specialist Chicago Pneumatic has issued some useful advice on how to adjust to the right levels of torque and why over tightening can cause problems especially when changing wheels. 

CP says that tightening specifications recommended by vehicle manufacturers are often overlooked in workshops and this can lead to avoidable downtime and have serious safety consequences. A common misconception often heard in the field by CP Technical staff is, “The more you tighten, the better”. However, this is false as in most cases, more torque means more tension applied to a bolt, resulting in overtightening which increases the risk of stud break.

Another myth that CP wants to dispel is that the more a van or truck is carrying, the more you need to tighten. Believing this can lead to overtightening and its disastrous consequences, so manufacturers’ recommended torque specifications should be followed at all times.

CP also point out that proper torque requires using the correct tools and procedures:

Manufacturers always provide recommendations for each tightening job, and these can be found in the specifications book, maintenance manual, or in online technical data. Before you start tightening you should double check to ensure your job is performed to the correct standard and to make sure that new materials and technology have not changed the required torque level.

A substantial amount of torque is “lost” or wasted by friction during tightening. Therefore, CP advise preparing the surface properly by cleaning all the elements to eliminate any rust, dust and dirt.

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 vehicle and its driver. It’s important to use the right combination of tools to prevent this and achieve the right level of torque. Christophe Roland, High Load Specialist at Chicago Pneumatic says, “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. ”

Chicago Pneumatic recommends 3 tools to prevent over-tightening; a Manual Torque wrench, a    Torque limited impact wrench + torque wrench and a pneumatic or cordless nutrunner, designed for tyre changing.

For more information and other useful tips go to the expert corner at www.cp.com