Best Torque Wrenches

• What you need to know
• Torque wrenches are used to tighten fasteners with a specific amount of force.
• A distinction is made between mechanical torque wrenches (beam wrenches, click wrenches, and indicating torque wrench) and electronic torque wrenches.
• For maintenance and repair on cars, motorbikes, bicycles, and lawnmowers, there are models in different sizes and with adapted tightening torques.
• When purchasing a torque wrench, consumers should look for good ergonomics, high precision, and easy handling.

Torque wrenches: precise and versatile

A certain torque is often specified for screw fastenings. This is where a torque wrench comes in handy: it is basically a socket wrench that emits a signal at a torque set by the user. Many torque wrenches have a mechanism that prevents further tightening. The tool allows a nut or bolt to be tightened safely without exceeding any limits.

Safe traveling with optimal tightening

With a torque wrench, users ensure the integrity of the connection. This is important in sanitation, for example. Here, excessive tightening forces can quickly damage the gas or water pipes.

For cars, torque wrenches are used to mount and dismount complete wheels. The identically set torque on a wrench helps to fix cylinder head gaskets between the valve cover and cylinder head. Mountain bikers also benefit from perfectly fitting screw connections. This means they can even tackle off-road tests without having to fear the breakage of an important screw connection.

An invention from the 1930s

The desire to tighten bolts and screws with a specific torque arose in the course of industrialization. At the beginning of the 20th century, more and more powerful combustion engines and vehicles were being developed. At the same time, the risks associated with manually tightened bolts and screws increased. The torque wrench with a beam as a torque indicator – which is hardly used today – was developed by the Chrysler Corporation in the early 1930s. In 1935, Conrad Bahr and George Pfefferle finally brought the first adjustable torque wrench with a click function onto the market.

Where the torque wrench comes in

The torque wrench made it possible for the first time to tighten bolts, nuts, and screws with a consistent torque that was independent of the user’s individual effort. With a precision tool like the torque wrench, the investment in high quality pays off, as the fastening can only be tight and secure if it is neither too loose nor too tight.

The consequences of a loose screw are obvious — which is probably why most drivers tend to overtighten wheel nuts when in doubt. The fear of losing a wheel on the highway is obvious. Less obvious, however, is the mechanical process triggered by overtightening a bolt or nut. The consequences, however, are no less severe: the mechanical stress in the bolt fastening, rim, and other wheel parts results in increased wear and can ultimately lead to the fastening breaking off.

This scenario can be prevented by using a torque wrench. The appropriate torque can be found in the manufacturer’s technical specifications. When it comes to cars and other machinery, safety is paramount. Accordingly, working without a torque wrench in the modern industrial world is virtually unthinkable. Nowadays, even do-it-yourselfers know the value of a good wrench and are increasingly moving away from rough manual tightening. After all, muscle power is not a good indicator of torque.

Changing wheels on your own

Car owners who manually change their tires every spring and fall should do so with the help of a torque wrench. In car workshops, due the hectic working pace, car wheels are often tightened to a uniform torque, instead of one specific to the model.

Car manufacturers always use different model-specific tightening torques for wheel replacement. Depending on the vehicle model, 40 Newton meters (Nm) more or less than the average value of 120 to 130 Nm may be required. Overtightening the bolts can lead to hairline cracks or distortion of the rims. Aluminum and magnesium rims are particularly sensitive to improper handling when tightening nuts and bolts.

Torque wrenches for cyclists

Increasingly, cyclists are also recognizing the usefulness of torque wrenches. If you take a look at the bolted connections on a high-quality road or mountain bike, you will discover specifications such as 3.5 or 9 Nm — an indication of the torque required for secure fastening. Cyclists who like to work on their bikes themselves are well equipped with a wrench for the torque range from 1 to 25 Nm. To also change sprockets and bottom brackets that require a higher tightening torque, you could consider a second torque wrench that is good for up to 65 Nm.

The right wrench for home, workshop, and business

A torque wrench is a safe, reliable and precise tool for car drivers, cyclists, and craftsmen. But how does the wrench actually recognize that a certain torque is applied? Torque wreches differ considerably in their design. The mechanics and, in some cases, electronics integrated into the tools are geared towards the various fields of application. For hobby mechanics, therefore, only a certain type comes into play. A distinction can be made between mechanical and electronic torque wrenches.

The different types

With the large number of torque wrenches of different types, sizes, and designs, it is often difficult to make a purchase decision. The main question should be for what purpose the wrench is needed and what the respective requirements are. A car driver, for example, needs a different torque wrench than a motorcyclist or a cyclist. This is already made clear by the different torque ranges. In the following, we explain the advantages and disadvantages of the different types of torque wrenches.

Indicating torque wrenches

The simplest type of torque wrench is the indicating wrench. With this type, a scale or a mechanical clock indicates the applied torque. This original form of torque wrench consists of a beam, which transmits the user’s force to the screw fastening and bends in the process. A second beam attached to the tool head which is not loaded serves as a reference. The torque can be read from the scale. Due to its simple design, the precision of the indicating torque wrench is not the highest. Since ascertaining the torque can be a bit awkward, this type is no longer widespread among do-it-yourselfers or craftsmen.

Click wrenches

Click wrenches are one of the most popular mechanical torque wrench types. The limit value is indicated by means of an acoustic and haptic signal. However, they allow the connection to be overtightened. Therefore, their usage requires some prior experience. With a little practice and the right tightening technique, however, accidental over-tightening can be easily avoided.

If you are using a torque wrench for the first time, you will be tempted to tighten the screw or bolt with a lot of force. When working with this precision tool, however, a different approach is called for, especially if it is a signal-generating click wrench without a fixed torque barrier. You should move the wrench calmly and evenly until you hear the click sound. But with a bit of practice, you will soon get the hang of it.

A variant of the click wrench is the slipper. This model builds up a slip after reaching the correct tightening torque and no longer transmits addtional force. One disadvantage of the slip wrench is its high price. This is why it is typically only used by professionals. For ambitious do-it-yourselfers who rely on the highest precision, a slipper is a great investment.

Mechatronic and electronic torque wrenches

Mechatronic and electronic torque wrenches are to be distinguished from mechanical wrenches. These special ratchets are mainly used in mechanical engineering.

What matters when purchasing

Experienced do-it-yourselfers and craftsmen appreciate high-quality tools. When it comes to torque wrenches, you should not go for the cheapest option, but look out for an advantageous price-performance ratio, instead. If you opt for quality when buying a torque wrench, you will be rewarded with robust and undamaged screw connections.

What size should the socket of the torque wrench be?

The size of the socket for the nuts depends on the area of application. 1/4-inch ( 0.64cm) torque wrenches are often used for bicycles. Wrenches of this size are also suitable for other work, for example, on mechanical or motor-driven gardening tools. For motorbikes, 3/8-inch (0.95cm) wrenches are mostly used. If you are looking for a torque wrench for your car, a half-inch (1,3cm) socket is the right choice. Wrenches with half-inch sockets are capable of transmitting the often required high torque of over 100 Nm.

Matching the torque range to the application

It is not possible to loosen luster clamps with a large screwdriver. Nor is a large torque wrench with a torque of up to 300 Newton meters suitable for repairing a bicycle. The required tightening torques for the screwed connections should be known before buying in order to be able to cover the majority of all necessary fastenings with a torque wrench.

Strong material for strong connections

For high-quality torque wrenches, manufacturers use correspondingly high-quality material. For example, corrosion-resistant chrome vanadium steel is often used for the tool shaft and the socket. The mechanics of good torque wrenches are solid and durable. With proper use, users can expect a long service life. Since a torque wrench is a precision tool, users should handle the tool with care.

Rough adjustment, fine adjustment, and readability

Good torque wrenches offer a two-stage adjustment. This often makes it possible to achieve better precision when maintaining the preset torque. When buying a wrench, consumers should look for easy handling and good readability. Since good lighting conditions cannot always be guaranteed, this point should also be taken into account when choosing the right tool.

Accessories for the torque wrenches

Most DIY enthusiasts and craftsmen who buy a torque wrench already have a set of nuts and bits. If you don’t yet have a set of sockets, it is worth buying a high-quality socket set. A suitable box or tool bag is also recommended for safe transport of the precision tool. In a shockproof case, the calibrated wrench will arrive at the workplace undamaged.

Notes on handling and care

Do-it-yourselfers and craftsmen should not deprive their torque wrenches of something they themselves indulge in after work: rest. Ideally, you should release the preload in the torque wrench after each use. That way, the accuracy of the wrench will remain high. How exactly the tension is released depends on the wrench in question. The operating instructions provide more information on the correct tensioning of the wrench.

Overtightening can be dangerous

Even before wheel fasteners or other screw fasteners break off, tension and fine cracks appear in specific parts, which can both impair service life and cause preliminary damage. However, it is not only the wheels that are at risk if wheel nuts are not tightened properly. Damage can also occur to wheel hubs, brakes, and parts of the wheel suspension. For drivers, the negative influences on safety-sensitive car parts are usually not visible, which is why they assume that they have been properly mounted. However, due to the dynamic driving forces that occur at high speeds, the dangers can manifest with a time delay.

Do not use additional extensions as levers

Most torque wrenches determine the applied torque via lever force. Therefore, an extension of the lever arm can lead to a falsification of the result. If the torque wrench is selected in the correct Newton meter range, it should not be necessary to use a temporary lever extension. An exception to this is a lever extension supplied or integrated by the manufacturer, as this extension has been taken into account in the design and calculation of the tool.

A torque wrench is for tightening — not loosening

A torque wrench should not be used to loosen tight screws and bolts. This can lead to material fatigue and falsification of the measurement results. Depending on the construction and design of the device, premature wear is also a possible consequence.

Care

Although it is a measuring device that requires careful handling, the torque wrench is a low-maintenance device. Dirt can simply be removed with a soft cloth. The internal mechanics require no care and are designed to be maintenance-free. While a torque wrench does not require a lot of maintenance, careful handling is advised.

A fall from the table onto the hard floor can affect the measuring accuracy. But even without such incidents, you should calibrate your torque wrench annually to ensure continued precision. To do this, send the wrench to the manufacturer or hand it over to a specialist company.

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