One of the most common questions we hear from golfers is: "Which AutoFlex model should I play?" It's a fair question, especially because AutoFlex doesn't use traditional flex labels (Senior, Regular, Stiff, X-Stiff) the way most shaft manufacturers do. Instead, Dumina uses swing speed ranges — a more precise and reliable way to match a shaft to your swing.
This guide gives you a complete swing-speed reference for every AutoFlex model — the SF Series, Dream 7, FlexOne, JOY365, AutoPower Flex, and AutoPower Snipe — so you can find your recommended model in about 60 seconds.
Traditional shaft fitting assigns flex based on feel: if a shaft feels too stiff, you go down a flex; if it feels too loose, you go up. That subjective approach works for conventional shafts, but AutoFlex's KHT technology changes the equation. Because the shaft walls are extremely thin (as little as 0.4 mm in some models), the flex profile responds differently to different swing speeds. The same shaft model can behave like a Regular for one player and a Stiff for another, depending on how fast they swing.
That's why Dumina publishes swing speed ranges rather than flex labels. Each model is engineered to perform optimally within a specific speed window. Play the right model for your speed, and the shaft loads and releases exactly as designed — delivering maximum energy transfer at impact.
Don't guess your swing speed. Most driving ranges and golf shops have a launch monitor or radar device. Even a basic device like a PRGR or Voice Caddie will give you a reliable driver swing speed number. Write it down — that's your starting point for finding the right AutoFlex model.
| Model | Swing Speed (mph) | Flex Equivalent | Weight (g) |
|---|---|---|---|
| SF305x | 70–90 | Senior | 41 |
| SF405 | 85–100 | Regular | 45 |
| SF505 | 95–100 | Stiff | 50 |
| SF505x | 100–110 | X-Stiff | 55 |
| SF505xx | 110–120 | XX-Stiff | 57 |
| Model | Swing Speed (mph) | Flex Equivalent | Weight (g) |
|---|---|---|---|
| Dream 7 305 | 60–75 | Senior | 39 |
| Dream 7 305x | 70–85 | Senior / Regular | 42 |
| Dream 7 405 | 80–95 | Regular | 44 |
| Dream 7 405x | 90–105 | Stiff | 50 |
| Dream 7 505 | 100–110 | Stiff / X-Stiff | 53 |
| Dream 7 505x | 105–115 | X-Stiff | 55 |
Finding the right model is only half the picture. Swing weight — the measurement of how heavy the club feels during the swing — plays a major role in how the AutoFlex performs for you. Dumina recommends a swing weight range of C5 to D2, depending on the model and the player's preference.
A lower swing weight (C5–C8) makes the club feel lighter and can help generate more clubhead speed, but may reduce feel for some players. A higher swing weight (D0–D2) provides more clubhead awareness and can improve consistency, but may feel slightly heavier through the swing.
The build matters too. Because AutoFlex shafts are extremely light, the head weight and grip choice have a bigger-than-normal impact on the final swing weight. This is why we strongly recommend a professional build — not just a simple shaft swap — when installing an AutoFlex. See our self-fitting guide for detailed swing weight setup instructions.
Beyond the premium SF Series and Dream 7, Dumina also offers KHT technology at more accessible price points through the AutoPower line:
These models use the same KHT thin-wall technology as the SF Series but with slightly thicker walls and fewer cosmetic options, which keeps the price lower while maintaining the core performance benefits.
Even with a perfect swing speed match, there's no substitute for a professional fitting. A qualified fitter will consider not just your swing speed, but also your tempo, transition, angle of attack, and spin numbers — all factors that can shift the recommended model up or down within the speed ranges.
For example, a player swinging 98 mph with a smooth tempo might be perfectly suited to an SF405. A player swinging the same 98 mph with an aggressive transition and late release might need the SF505 for better stability. Only a launch monitor and an experienced fitter can make that call.
Plus, the fitter will handle the critical build details — tipping, swing weight adjustment, and grip selection — all of which have a significant impact on how the finished club performs. Find an authorized Dumina dealer for a proper fitting.
Match your driver swing speed to the chart above for a starting point, then get fitted to confirm the model, tipping, and swing weight. That's the fastest path to experiencing what KHT technology can do for your game.
Visit an authorized Dumina dealer for a professional fitting, or shop online at our official retailers.