Growing up, torque wrenches were a seldom-used item, but as bike parts have become increasingly delicate, and my own obsession with precision has grown, they've become indispensable tools. 🤔
Beam-type torque wrenches are frequently touted as being more accurate than the more popular click-style, but I've yet to see convincing evidence for this widely held opinion. A quality wrench will be accurate to less than 4% at max, and less than 1% in the first 20% of its span—that's well within the range spec'd for most fasteners. A bicycle crankarm fixing bolt torque spec is 305-391 in-lbs/34.5-44.2 Nm, a small-block Ford cylinder head stud calls for 65-70 lb-ft/88-95 Nm—that's a 28% range for the crankarm, and 7.6% for the head stud.
Click-style wrenches easily cost twice as much, if not more, and have other minuses:
• They can lose accuracy if dropped
• If the spring isn't backed off all the way in storage, they may lose calibration
• They require periodic recalibration to ensure accuracy
• A ham-fisted mechanic can still overtorque a fastener by continuing to load the wrench after the click
Beam-style wrenches are also not without problems:
•You have to see the scale to read it
•They're subject to parallax error—you must view the scale squarely, for accuracy
Both wrenches may lose calibration if taken beyond their approved torque range.
Click-type wrenches are terrific in hard-to-reach spaces, where there's no clear sight line to the tool. But beam-types are indispensable for things like checking preload on gearboxes and bearings, able to determine the force required to rotate a part.
It's tough to beat the satisfyingly positive Click! and tactile reward that comes with snugging a fastener home with a click-type wrench, but I tend to favor beam-types when I can see the workspace clearly. Which means for bicycles and motorcycles, I like beam wrenches. On cars, I'll use a beam if I can but frequently only a click-type wrench will do.
Either type is acceptable. The important thing is to own one and use it. It's a good habit. 😎