69 RA: neither soft nor stiff — the honest stiffness

RA is one of the most misused numbers in tennis. It measures frame stiffness at impact — how much the frame flexes when the ball hits. Brands push it to the extremes in both directions, and both extremes cost you something. Here's why we fixed the whole adult range at 69.

What RA actually drives. Stiffness governs yield (energy returned to the ball), dwell time (how long the ball stays on the strings) and comfort. Stiffer = more return and a short, crisp contact; softer = a longer, more muffled contact. It is not, on its own, “power” or “comfort” — it's a trade-off.

How the market distorts it. Some frames inflate stiffness to manufacture power (the ball springs off a rigid platform) — great on paper, harsh on the arm and vague in feel. Others smother it to chase comfort — pleasant, but “dead”: the ball lands short when you brush. Both hide the real variable — trajectory — behind a stiffness number.

Why 69. It's the honest floor of modern yield. Modern tennis is tangential: you brush to create spin, and that costs linear energy. You need enough frame yield to keep depth — but not the rigidity that kills feel and comfort. 69 sits exactly there: enough response for the modern stroke, without the harshness. Not soft, not stiff.

So where does comfort come from? Not from a soft frame. It comes from the right setup (mass and balance that let you relax), the right string (that absorbs and snaps back), and a properly fitted handle. We remove what holds you back; we don't add fake softness.

Beyond RA: the two numbers that say more. RA is a single point. The stiffness profile (how stiffness is distributed along the frame) and torsional stiffness (resistance to twist) tell you far more about how a frame really behaves. We're measuring the stiffness profiles of our frames and will publish them on each product page.