Torque is a rotational force that can be measured in inch-pounds (in-lb), foot-pounds (ft-lb) or Newton-meters (Nm). When you twist a threaded fastener (like nuts and bolts on your bike), it produces friction that binds the joint together. Each fastener on your vehicle should be optimized for a certain force level, defined as the “torque range”.
Sometimes, you can see the required torque spec clearly visible on the side of the bike sections – check the stem or the seat post. For other fasteners (for example, on your wheels), read the manufacturer’s manual.
Why is torque measurement essential for fasteners?
Since every fastener is made to be filled with a certain amount of friction, lugs/nuts/bolts that are too tight or too loose can trigger some huge issues during your ride. To avoid these issues, you should use torque wrenches in such a way:
- Under-tightened bolts could make loose when you’re riding. The danger of bolts coming loose varies from rattling or clanking the vehicle parts, premature damage on certain bike parts, and/or running or dropping the parts. This could be a major problem that contributes to the collision;
- Over-tightened nuts can bend the threads or sections of the vehicle they keep in place or can cause the bolts or sections to split due to stress. This is a special concern with carbon bike frames and sections that can be destroyed under the applied force and weight if you push too hard;
Measure torque before using a wrench
The torque wrench is a device for calculating the rotating resistance of the fastener. The only way to be completely confident that you fixed the fasteners on your wheel safely is to use this tool. There are two most popular types of torque wrenches:
- Beam-type torque wrenches have a basic shape that can be used to secure a broad range of fasteners. To use these tools, connect the right bit to the wrench socket. Hold the handle and adjust the fastener until the torque spec fits the reading at the end of the pointer. Just make sure the cursor is empty at rest. When it’s off, you should use an instrument like a screwdriver to snap the pointer back into position between two ending points.
- Click-type torque wrenches are the most popular tools that can be applied for fastening or loosening the bolts. Make sure the picked wrench suits the torque requirement on the fastener you intend to tighten. To function, connect the right bit to the wrench socket. Pick the appropriate torque setting and secure the fastener before you hear and feel the release of the torque with the specific “click” sound. Preset torque drivers are handled in the same way.
Check the manual to each tool before using it. Typically, different torque wrenches are used in the same way but the applied torque range varies.
How to use a torque wrench: a two-step instruction
A torque wrench is a special instrument built to twist the lugs/nuts/bolts at different levels. It’s almost always used to operate on vehicles and motorcycles, so it should only be used to secure it. Torque wrenches are hand-adjusted, and you don’t require any other equipment for fastening or loosening the nuts. To use a torque wrench, change the handle and configure it to a particular torque point.
Using the tightening part at the end of the handle may secure it in place. Then, place it over the plug/nut/bolt, and twist it clockwise to make it secure. When finished, change the handle settings back to 0 and lock it in a secure spot. Keep your torque wrench tuned at least once a year to ensure increments and readings stay correct.
Despite the type of a chosen torque wrench, you should follow 2 steps:
1. Adjust the tool:
1) Loosen the fastener at the top of the tool’s handle. Check at the ending point of the handle to locate the drive head that will perform within the torque range when tightening a fastener. Typically, it looks like a plastic or metal cap caught in the back of the wrench. It’s always a different range from the majority of the torque wrench. Turn it clockwise by hand to remove the bit so that you may adjust the settings of the tool. You don’t need to take it off your hammer, just loosen it until you don’t notice a lot of resistance.
2) Check the settings and features of a specific wrench. Inspect the range around the handle to locate the increments – this would be the configuration of the applied torque. There would be 1 set of larger numbers on the wrench body and 1 set of smaller numbers on the handle. As Paul Meyer from AutoThema said, the lower figures are the lesser ones, and the bigger ones are the big ones. Torque is determined by foot-pounds (ft-lbs). Your torque wrench will display 2 sets of numbers on the scale of a torque wrench. The lower figure is the foot-pound ratio. The greater amount is the ratio in Newton-meters.
There’s also a middle line on the wrench to indicate where the handle is mounted. If the ending point of the handle is 200 on the tool’s range and the smallest increment is 5, then the torque level for the handle is 205 ft-lbs.
3) Switch the lever to boost or lower the torque levels on the wrench. Hold the tool on the side opposite to the fastener. Switch the handle clockwise to lift it, or to lower it clockwise. Start spinning the handle until you hit the target hash mark. When you decide to hit a certain torque number, through the handle to the increment within 5 ft-lbs overall. So if you realize that you ought to hit 140 ft-lb, lift the handle to the hash mark about 135-145 ft-lb. Several torque wrench handles are slipping up and down instead of bending straight into the position.
4) Flip the handle to adjust the tool. When you’re near to the number you want, switch your eyes from the handle height to the dial itself. Ignore the readings as you gently click the knob. When you move clockwise, the amount is rising. When you move in the clockwise direction, the amount goes down. There are a couple of negative numbers after 0 and you can go down a little as well. Some wrenches turn independently of the handle, so you will twist it by rotating the button, not the handle.
5) To calculate the required torque you need to apply, add the smaller digit on the handle to the amount on the larger hash label. After you have changed the handle’s height and turned the lever, measure the overall torque and ensure that it is correctly calibrated by adding the numbers together.
The example: take the increments (torque range) on the handle and add the amount on the dial to get the required torque setting. And if the increment is 4 and the handle is 60, the gross torque is 64 ft-lbs. You must add the negative figures. If your increment is 130 and the step of the range scale is – 2, you should add 130 to – 2 to get 128 ft-lb of the applied torque maximum.
6) Tighten the locknut back to the end of the lever by hand to secure it. To secure the position of the torque in the wrench, turn it back to the shaft. Wear the lever on the non-dominant side and hold it steady. Twist the bolt (or any other fastener) clockwise by hand before it doesn’t move any further. It is going to keep the handle in place. If the fastener is closed, you can’t change the setting of the torque.
2. Tighten the fastener properly (nut/lug/plug/bolt):
1) Place your socket on your wrench’s ending point. To use your torque wrench, begin by sliding a socket that fits the fastener to the drive head. Whether you have an extender or connector that you are using, you should slip it through the head gap instead. These tools come in various types, but connectors are nearly always compatible. Torque wrenches are costly, and they only come in one size – though, you may invest in the set of torque wrenches of different sizes.
2) Twist the fastener by hand before capturing the threads on the screws. Before twisting, you should secure and position the fastener over the thread for the screw. Turn the fingertips around the vehicle’s fastener clockwise before the threading has captured the screw. Switch the nut or bolt until it is no longer rotated by hand. Torque wrenches have a lot of strength, so if the nut or bolt is not properly compatible with the screw, you might break the threading on all of them.
3) Attach the plug to the top of the fastener that you want to attach. Keep the handle of the torque wrench in the non-dominant side with the fastener on the threading. Using the dominant hand to direct the connector, or extender to the fastener. Slide the wrench over the bolt before the two bits are clear.
4) Hold the handle, then make it turn in the clockwise direction. Keep rotating while locking the bolt. Bear in mind that almost all tools of this type can fully turn automatically. That is why you don’t have to reposition the bolts and nuts. Sometimes you should turn the wrench in the counterclockwise direction. Handheld wrenches without digital features, you may need to reposition the bolts and nuts. Then force the tool back. But make sure to work within the limits of the tool’s torque range.
5) Stop spinning the handle when pressing the fastener. When the automated wrench turns as you move it, holding the nut or bolt closed. If you start clicking as you turn it clockwise though, avoid squeezing the nut or bolt. The clicking noise when the fastener is tightened means that you have achieved the required torque point. Avoid turning it on the electric wrench until you hear the knob fighting. And if the handle is set to 200 ft-lbs of torque, the bolt is fixed to that point as soon as it begins clicking as you attempt to fix it.
Handheld wrenches can automatically adjust once the nut or bolt has been set to the appropriate torque range.
Tips for users of torque wrenches:
- Never hold the wrench near the socket – hold the very end;
- Even the most calibrated wrenches won’t do for loosening the bike’s bolts. Bikers should pick Allen keys instead;
- Before storing the wrench (especially if it has many torque settings), you should return the settings to 0;
- Always lubricate the threads of the fastener on which you are going to use a torque wrench. Dry threads may affect the torque accuracy readings;
- Torque wrenches won’t be able to tighten the cross-threaded bolts;
- It is better to tighten the fasteners in 2 steps – the first stage to the half torque value and then to the final torque range picked for the fastener;
- Before using a wrench, you should clean any rusted or dirty threads of fasteners.
Final thoughts
Now when you know how to use a torque wrench safely. Make sure to follow the manufacturer’s directions if the manual comes with the tool. Always use a wrench with safety-toe shoes and without exceeding the torque limits. Otherwise, your safety on the road would be compromised.