Lug nuts are basically fasteners specially used for securing wheels on a vehicle. If you've ever changed a car tyre or seen someone do it, you would've noticed people going crazy while tightening them.
Little do people know that each of these little nuts has an optimum torque rating which defines the right amount of tightness required for the specific nut on the car.
Torquing
Lug nut torquing is expressed in foot-pounds. Tighten the nuts a quarter turn at a time following the criss-cross sequence shown above. This is very important. Failure to tighten the nuts in this criss-cross sequence will cause a misalignment of the wheel. Continue until all nuts are tightened to the manufacturers specified torque.
Your car owner's manual is your bible when it comes to understanding your manufacturer's specification for torquing the lug nuts. Always follow whats written in your owner's manual and if you don't have one, you can visit an official dealer or service center of your vehicle's manufacturer to get the information.
CAUTION: Improper torque can cause distortion, fatigue cracks or alignment problems. After running the vehicle for a short distance, check the nuts for tightness. Parts will usually seat naturally and torque on nuts will drop. Re-tighten all nuts to the specified torque.
Also Read: Tightening Lug Nuts: The Criss-Cross Pattern Explained
Tools
There are basically two tools you can use to tighten the lug nuts:
1. Impact Drivers: Impact drivers don't really offer controlled torquing that stops at one measurement. Electric, often cordless, impact drivers provide a rotational hammering action and are used in situations that require excessive overdosing of torque.
However, it is possible to utilize impact drivers by using a torque limiting extension bar. The torque limiting extension is designed in such a way that it starts to flex at a specific torque rating. The flex from the extension is able to absorb the extra torque from the driver which stops the transmission of any extra torque immediately. The extension bars come in kits and are usually color-coded for different torque values. For example, a black bar for 30 ft/lb, green for 65 ft/lb and so on.
Wrench: Wrenches are of two types - one allows you to measure the specific torque you're applying while the other is a generic one without such features. The former is called a torque wrench which allows you to apply a specific torque to the lug nuts. It usually comes in the form of a socket wrench with special internal mechanisms.
A torque wrench is optimal for lug nuts as it allows the operator to set the required torque to be applied to the nuts so that an optimal fitment can be achieved. This helps avoid any over-torquing or under-torquing of the lug nuts, ensuring proper alignment of the tyres. It is also much more safer.
Image Credits: yourmechanic
