I co-introduced the first consumer tensiometer in 1985 and still sell them today, so I have a bias (or 2) and some perspective.
What do they do?
Experienced builders are right, a great wheel does not require a tensiometer. Even for beginners, everything you need can be learned by trial and error.
Using a tensiometer reduces the chance of incorrect spoke tension, the most common fault of wire wheels. Both the average and the distribution of tension must be in a narrow range for components to blend optimally into a single, rugged structure.
Squeezing spokes, plucking them, and feeling nipple turning resistance are ways to monitor tension besides a dedicated measuring tool. A tensiometer prevents misinterpretation from:
– Thick spokes feeling tighter than thin because they are stiffer to squeeze.
– Nipples suggesting higher tension if they resist turning due to corrosion or lack of lubrication.
– Material and geometry of rim holes and nipples greatly affecting twisting friction.
Tensiometers can see through all of this, a boon for beginners.
A training tool
More than enabling appropriate tension, as you see tension numerically, associations form without conscious effort. You become trained to sense tension just as a heart rate monitor trains you to know your rate.
After thousands of observations, wheel tension becomes more and more intuitive. Rim models, tensions with various spokes and nipples, time to finish, and eventual long term outcomes, all become associated. This mental landscape is best built with a tensiometer and as experience accumulates your expertise grows. This intuition separates masters from learners and enables very fast builds.
Since numbers are better than adjectives like “tight,” “not so tight,” “really tight,” etc.; component makers, builders, journalists, and riders can exchange ideas and discuss experiences with a shared numerical language. Kilograms of force and newton meters enable instruction and conversation. This ongoing discussion shapes product development and wheel designs. Without it, the cycling world would be more random and hazardous.
These days it is best to show you use a tensiometer and have respect for the subject. Sure, it’s part marketing but people tend to make snap judgements, especially when trust is involved. There are so few tools in wheel building despite its engineering feat. Callouses and name dropping go only so far to establish credibility. Modern consumers will often defer to a very neat and well equipped workshop over a spartan layout in spite of good reviews.
There are two levels at work in your building. One is the wheel before you, wanting to be the best it can. Two is the learning brought by experience. Building your intuition for component, especially spoke, behavior is an immense treasure – the key to speed, a reservoir of patience, a resource for advising riders, and a stimulus for design insights. No wonder many builders…