Product Test: Torque Wrenches
Correct torque values are the difference between failure and prolonged success
Correctly tightened fittings are critical for reliability and safety, making these the main reasons for using a torque wrench. Ensuring components are correctly fitted needs to be more specific than tightening as far as you can and then a bit more. Equally, components that are under-tightened, such as cylinder heads, will prematurely fail – and without a torque wrench this is easily done. For example, a fitted engine offering resistance to your ratchet turns makes it easier to tighten 90 lb ft cylinder head nuts than a loose engine on a trolley or the floor.
Torque wrenches are available in an array of drive socket sizes, measuring scales and physical size, so matching one or more to your needs depends on intended use. A one-off engine rebuild is a different discipline to regular suspension work for off-road use, for example, or for fitting a variety of wheel types in a professional environment.
All the wrenches tested are ISO 6789 compliant, meaning they are calibrated for accuracy before sale. A certificate issued with the wrench will give the calibration results you can expect at different settings across the torque ranges. This is important because it allows you to fine-tune the wrench to critical settings if necessary. If your wrench use is confined to an annual service or one-off restoration, buy a wrench with the broadest range possible to match the torque values provided in a workshop manual.