How to use a click torque wrench
Unlock the handle, turn it until the two scales read your value, and lock it again. Pull slowly and evenly on the handle and stop the moment it clicks. Store it at its lowest setting, and have it checked every 12 months or 5,000 uses, and before using it again if it has been dropped.
Sources checked
Pick one that reaches your value
A click wrench can only be set within the range on its scale. Tekton’s micrometer wrenches come in two ranges: 2 to 20 N·m on a 1/4 in. drive, and 20 to 140 N·m on a 3/8 in. drive. The vehicles on this site take 62 to 165 lb-ft on their wheels (central-lock wheels aside), and 168 of the 443 need more than 140 N·m (103 lb-ft), so check the top of the range before you buy.
If the wrench reads in different units from the spec, convert the spec first with the torque converter; the torque units guide explains what each unit is.
Setting the value
A micrometer wrench has two scales. The main scale, marked with the major steps, runs along the handle body; the micrometer scale, with the fine steps, runs round the knurled handle above the locking collar. The value is where the two meet.
- Unlock the handle. Pull the locking collar down until it rests against the knurled handle, and hold it there.
- Turn to the nearest major step. Turn the handle until its top edge lines up with the major graduation closest to your value.
- Fine-tune. Keep turning until the mark you want on the micrometer scale lines up with the vertical line on the main scale.
- Lock it. Let the collar go and try to twist the handle both ways. It should stay put with the collar fully up; Tekton’s handle only locks on an exact step, not between two.
Pulling to the click
- Fit the socket to the drive and onto the nut or bolt.
- Hold it at the groove. Tekton’s manual has your middle finger resting in the groove in the knurling, which is where the pressure should go; held elsewhere, the reading is off. Don’t slip a pipe or extension over the handle: that makes the torque wrong and can damage the wrench.
- Pull slowly, with even pressure. Pulling fast or hard can carry you past the setting before you notice the click, and bearing down with your body weight can overshoot it or hurt you.
- Stop at the click. Stop the moment you hear or feel it. Pulling on after the click can overtighten the fastener; take extra care at low settings.
Not for loosening
Don’t use a torque wrench as a ratchet to break a fastener loose. If the wrench has a direction switch, Tekton’s manual says to turn it to its lowest value before setting a value in the new direction; you may hear a soft pop as the mechanism shifts.
On a wheel, the click comes at the end of a sequence: the lug nut guide covers the star pattern and the passes.
Crowfoots and adapters
A crowfoot wrench or torque adapter on the drive can move the fastener away from the drive square, which changes the wrench’s effective length. Turned at a right angle to the handle, it changes nothing. Pointed along the handle, beyond the drive or behind it, it does, and Tekton’s manual has you set the wrench to:
Setting = spec × L ÷ (L + C); the extension calculator works it out for you. L is the wrench’s effective length, from the center of the drive to the center of the handle, measured with the wrench set to the spec. C is how far the tool moves the fastener: plus if beyond the drive, minus if behind it. For a 110 N·m spec on a wrench 408 mm long:
| Fastener | Set the wrench to |
|---|---|
| 28 mm beyond the drive | 102.9 N·m |
| At a right angle to the handle | 110.0 N·m |
| 28 mm behind the drive | 118.1 N·m |
Storing it
- At the lowest setting. Store it at the lowest value on the handle, not at zero and not below the scale. That takes the load off the spring inside, which would otherwise tire and throw the reading off.
- Clean and dry. Wipe it with a clean, dry, lint-free cloth. Don’t soak it in any liquid or cleaner, which can damage the parts inside.
- Exercise it after a rest. If it hasn’t been used for a while, click it a few times at a low setting so the lubricant inside coats the moving parts again.
When to have it checked
Tekton’s manual calls its wrench a precision measuring instrument, and like any other it’s checked on a schedule. Unless your workshop’s own schedule sets another interval, ISO 6789 sets it at 12 months or 5,000 load cycles, counted from the wrench’s first use. A wrench that has been dropped or damaged should be tested before it’s used again, whatever its date.
Under ISO 6789-2, an adjustable click wrench is checked against a torque tester at the bottom of its range and at 60% and 100% of its maximum, and may read up to 4% off at each: about 5.6 lb-ft on a 140 lb-ft wheel. Tekton rates its own at ±3%.
Questions
Should I turn a torque wrench back to zero after use?
No. Store it at the lowest value printed on the handle: that takes the load off the spring inside, which keeps it accurate. Tekton’s manual says not to turn the handle below that setting.
Can I loosen lug nuts with a torque wrench?
No. Tekton’s manual says not to use the wrench as a ratchet for breaking a fastener loose. Use a breaker bar or the lug wrench, and keep the torque wrench for the final tightening.
How often should a torque wrench be calibrated?
Unless your own schedule says otherwise, ISO 6789 sets the interval at 12 months or 5,000 load cycles, counted from the wrench’s first use. Have it checked before then if it has been dropped or damaged.
How accurate is a click torque wrench?
ISO 6789-2 allows a click wrench to read up to 4% off at each point it’s tested. On a 140 lb-ft wheel that’s about 5.6 lb-ft either way. Tekton rates its micrometer wrenches at ±3%.
Does a crowfoot or adapter change the torque?
Only if it moves the fastener away from the drive square along the handle. Turned at a right angle to the handle, it needs no correction; pointed along it, set the wrench lower (beyond the drive) or higher (behind it), as worked out below.
Sources
- Tekton: Micrometer Torque Wrenches Product Manual: setting the value, applying torque, storage and off-axis correction (checked October 23, 2026)
- ELORA: Calibration service: how often a torque wrench should be checked under DIN EN ISO 6789:2017 (checked October 23, 2026)
- Atlas Copco: STpad user guide: ISO 6789-2:2017 parameters for click wrenches (test torques and maximum deviation) (checked October 23, 2026)
Spotted a number that doesn’t match your manual or a source? Tell us; corrections are logged on the sources page.