How to use a torque wrench
Bike are expensive and require a basic tool kit to maintain and look after them properly. A torque wrench is a simple but essential tool that will protect your bike from damage caused by overtight or undertight bolts. Therefore it’s important to know how to use a torque wrench correctly.
What is a torque wrench?
Bikes are a collection of components held or clamped together by a series of bolts. They secure everything so they they are safe to ride. It’s tempting to just do them up as tight as possible but if a bolt is too tight, it may actually damage your bike. If it’s not tight enough, components risk coming loose.
All bolts on a bike are given a specific torque or a small range they should be tightened to. Torque is the rotational force applied to a bolt when it is tightened. This is where a torque wrench comes in really handy. Without one, it’s simply guess work but with a torque wrench you can set it to the desired torque (measured in Nm, Newton-Metres), tighten the bolt and it will ‘click’ when it reaches the correct amount of force. It’s important to stick to these limits. Bike manufacturers work them out specifically for each component. Most components have the torque printed them. If not refer to the manufacturers specifications.
Further Reading
Choose the right torque wrench
There are different torque wrenches available so choosing the right one for your bike is important. The torque required on bikes is is usually quite low so a bike specific wrench is probably the best choice. They tend to be smaller which reflects the amount of torque needed. Bigger, longer torque wrenches may be more suited to automotive scenarios and may not offer the much smaller torques 2-15Nm, typically found on a bike.
It’s also important to have the right bits for the end. Allen key and Torx bits are the most common. Make sure you have the right sizes for all your bolts.
Some torque wrenches are pre-loaded to a fixed torque, say 5, 6 or 7Nm. These can only be used on bolts that require that specific torque but can be useful and quick for bolts on stems and seatpost clamps, for example.
Using the wrench
- Set the torque value
Refer to the manufacturers spec or take the number printed on the component. Adjust the the torque wrench to the desired value. -
Attach the correct bit
Fit the appropriate bit for the bolt, make sure it is seated correctly. -
Tighten the bolt
Hold the handle perpendicular to the bolt. Tighten slowly until the wrench ‘clicks’ which indicates it has reached the desired value. If you are tightening a number of bolts, tighten them in a diagonal or opposite pattern. -
Zero the wrench
When you have finished with the tool, always dial it back down to zero to store it.
Remember, proper torque prevents over-tightening (which can damage components) and under-tightening (which can lead to safety issues. Happy cycling! 🚴♂️🔧
