Reading a Gram Scale Versus a Flex Board
Two of the most useful instruments on a fitting cart measure completely different things — and confusing what each one tells you is a common source of fitting mistakes.
Walk into most club-fitting shops and you'll find a deflection board bolted to the wall and a digital scale sitting somewhere less prominent, often treated as an afterthought. Both instruments matter, but they answer entirely different questions, and it's easy to assume one can substitute for the other. It can't.
What a Flex Board Measures
A deflection board clamps a shaft at a fixed point, applies a standardized load at the tip, and measures how far the tip bends. That reading gets converted into a flex classification or a numeric deflection value, describing the shaft's stiffness profile — how it behaves under load, and often how that stiffness is distributed between the tip, mid, and butt sections.
What a Gram Scale Measures
A bench gram scale does one thing: it weighs the shaft. No load, no bending, no classification — just a direct mass reading, typically accurate to a tenth of a gram on a good bench unit. It tells you nothing about stiffness and everything about how much material the shaft carries and how much effort your swing has to spend moving it.
Stiffness and mass are independent properties of the same object. Measuring one tells you almost nothing reliable about the other.
Why Fitting Carts Skew Toward the Flex Board
Flex has historically been easier to market and easier to standardize into a single letter consumers recognize — Regular, Stiff, Extra Stiff — while weight has stayed a specification number buried in product literature. That marketing history is part of why so many fitting conversations start and stop at flex, even though weight is arguably the more direct measurement of what a golfer's hands actually feel during the swing.
Using Both Instruments Together
On our bench, every shaft gets weighed before it's flex-tested, and both numbers go on the same build sheet. Flex tells us how the shaft will bend under your load; weight tells us how much effort your transition has to spend getting it there. Neither number substitutes for the other, and a fitting that only records one is missing half the picture.
The Takeaway
If your last fitting produced a flex recommendation and nothing else, you've only seen one side of the shaft's behavior. Ask what the shaft weighs bare — it's a five-second measurement that adds a genuinely separate piece of information.
See Both Instruments in Action
Every fitting session at our bench includes both a bare-shaft weigh-in and a flex check.