Relationship Between The Specified Torque & Wheel Nuts When Replacing Tires

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Aside from tire assembly to wheels, which requires specialized equipment and skills, many people would like to save on labor costs by replacing (removing and installing) whole wheels, such as spare tires and winter tires, by themselves.

However, the tightening torque for the nuts required when installing wheels on a car is specified, and in some cases, there is a risk of serious problems if the torque is not correct.

In this issue, we will explain the existence of the specified torque to be observed when changing tires and its relation to wheel nuts (bolts).

What Is The Important Specified Torque (Tightening Torque) When Replacing Tires?

The proper tightening torque for tire wheel nuts on automobiles is 10 to 12 kg (approx. 100 to 120 N-m) for standard cars and 8 to 10 kg (approx. 80 to 100 N-m) for light cars.

However, it varies depending on the type of car and vehicle weight, as well as the frequency of highway driving and daily driving distance, so it is necessary to do a thorough preliminary check for proper torque when replacing tires yourself.

How To Check The Specified Torque (Tightening Torque) & The Correct Way To Tighten

If you want to check the specified tightening torque for your car, refer to the car’s owner’s manual. Another way to check is to contact the sales dealer of the model of the car you are driving.

As for the correct tightening method, you need to tighten the nuts by using a cross wrench or impact wrench in the order of diagonal lines for 4 and 6 nuts and in the order of a star for 5 nuts, so that the tightening condition will not be uneven.

The final step is to use a torque wrench to adjust to the proper tightening torque, so the initial tightening should be done with a slight “weak? So, the initial tightening should be done with a slight “weak” amount of effort.

Since it is unexpectedly difficult to adjust the tightening torque, it is recommended to ask a professional contractor to perform maintenance on tires to ensure that all possible measures are taken.

What Types Of Nuts Are Used When Changing Tires?

In a word, there are actually several types of wheel nuts for tires according to size, shape, and use, and you must choose the one that fits.

  • Diameter of the hub bolt on the car side
  • Pitch (thread) of hub bolt
  • The shape of the mounting surface (taper, flat, spherical)
  • Through nut or bag nut

As mentioned above, there are various types of nuts, from the size of the nut to the difference in threads, to the shape of the mounting surface, to the bag nut where the hole is not visible, to the through nut where the hole is visible from the outside, to the steel nut, duralumin nut, Chromoly nut, and titanium nut, etc.

Nuts made of various materials exist. If the wheels are brand-name and expensive, they may have “lock nuts” that cannot be removed without the original sockets, and if the sockets are lost, the work may not be possible even with professional help.

In such a case, the supplied socket may not be able to be removed even by a professional.

What Will Happen To The Bolt If The Specified Torque (Tightening Torque) Is Incorrectly Applied When Changing A Tire? What Are The Dangers?

There are two types of cases in which the specified torque is incorrect: too tight or too weak. In the case of over-tightening, the entire hub bolt may be threaded off, resulting in costly repairs.

In the worst case, the entire wheel may come off the vehicle, endangering not only the driver but also others. When replacing tires, be sure to install them according to the specified torque (tightening torque).

In addition to tire replacement, it is generally safer to have a professional take care of suspension-related servicing and maintenance, such as brakes and steering.

If you are not accustomed to changing tires, or if you are unsure about the specified tightening torque, ask a professional to change your tires.