One of the key aspects of DIY car maintenance that is often overlooked is checking the
torque on the wheel nuts. Many drivers know of checking the tyre air pressures but ensuring that the wheel nuts themselves are properly secured is also critical, this is especially important when replacing wheels after a puncture or 'blow out'! Just as there are the consequences of increased tyre wear and poor handling by pumping too much or too little air into tyres, there are more significant dangers if over-tightening or insufficient tightening of the wheel nuts occurs. Most cars are supplied with cross-type wrenches or wheel braces which are designed for speedy wheel removal and installation.

However, to ensure correct assembly and the security of the wheels staying where they are intended to be, on the car, a torque wrench should be used for final controlled tightening to the vehicle manufacturer's specifications.

Although garages and workshops frequently remove and tighten wheel nuts with an electric or air impact gun for speed, it is always recommended by the vehicle manufacturer that final stage tightening takes place with a suitable torque wrench.

This is therefore no different for the DIY maintenance enthusiast who does not have the luxury of a powered gun but instead has only a cross type wrench or wheel brace to work with.

The required torque, normally specified in Newton metres (Nm) or Pounds feet (lbf.ft) can be determined by consulting the 'owners manual' or 'general maintenance book' supplied with the vehicle and is usually stated in the section on tyre care and maintenance.

Torque specifications for wheel nuts should always be adhered to and the tightening sequence should always be so that opposing nuts are tightened, working around the wheel in a clockwise direction.

The tightening sequence ensures that wheels are fitted square to the wheel hub, thereby preventing any vibration that would not only make driving uncomfortable but could also pose a danger if severe enough to hamper steering and vehicle control.

It is imperative that an appropriate quality torque wrench is used to ensure that the correct torque is applied. The torque specified in the 'owners manual' has been determined by the manufacturer to be sufficient to ensure even clamping load over the complete wheel so that environmental factors such as changes in temperature, vibration and severe breaking/acceleration will not deteriorate the quality of the bolted assembly.

Norbar Torque Tools, having over 60 years exper ience in the industry, is pleased to be able to offer a complete range of torque tools for both the DIY and Professional Mechanic. A special DIY tyre care kit is currently available consisting of a `click type' torque wrench with Nm and lbf.ft graduations and a selection of sockets to suit most conventional wheel nut sizes.

For further information please contact Miss Dione Chong or Mr Lim Chi Kah at Norbar
Torque Tools Pte Ltd on 6841 1371.