Analysis
Flex, weight and kick point: what a golf shaft changes
Flex, weight, kick point and torque explained: what each one is supposed to do, what the evidence says it actually does, and why a swing-speed chart is only the start of choosing a shaft.
The flex letter on the sticker, “stiff” or “regular”, is the part of a shaft club golfers talk about, and the industry has never agreed what it means.
Flex: useful label, no standard
Flex describes how much the shaft bends under load. The usual ladder runs L (ladies), A (senior or “amateur”), R (regular), S (stiff) and X (extra stiff), and charts match each one to a driver swing speed. A recent MyGolfSpy guide puts regular at roughly 84–96mph, stiff at 97–104mph and extra stiff at 105mph and above.
The same guide admits that flex is not standardised. One brand’s stiff can play closer to another’s extra stiff, so a golfer swinging 100mph could sensibly end up in either. The letter tells you where a shaft sits within its own family, not how it compares with a shaft from someone else.
Flex does change ball flight. In a fitting example published by Erik Henrikson of PING’s fitting science team, a golfer with a 95mph swing launched a regular-flex driver shaft about 2° higher, with roughly 360rpm more spin and 11 yards more carry than a stiff option, and with a tighter dispersion pattern. That’s one player, and the two shafts also differed in weight and model, so it isn’t a rule.
Three golfers, three flexes, no pattern
An older MyGolfSpy Labs test looked at this independently. Three golfers hit the same driver head with regular, stiff and extra-stiff versions of one shaft, matched for weight, torque and bend profile, on a FlightScope launch monitor. No consistent pattern emerged across the three. Distance swung by up to 22 yards depending on flex, and the fastest swinger lost ball speed in the extra stiff a chart would have handed him. As the testers put it, “clubhead speed is only a starting point”.
Three golfers is a tiny sample, but it lines up with what PING’s engineers have said more recently: individual golfers respond differently to the same shaft, partly because they change how they swing based on what the shaft feels like. Tempo and how hard you load the club at the start of the downswing matter as well as raw speed.
Weight: the easiest spec to compare
Weight is easier to compare across brands because grams are grams. Driver shafts typically sit around 55–65g, steel iron shafts around 95–120g and graphite iron shafts around 65–85g, according to MyGolfSpy’s guide.
In PING’s explanation, heavier shafts tend to produce a lower flight that leans left to right, while lighter shafts lean towards a higher, right-to-left flight. We think weight deserves as much attention as flex because it shapes how the club feels to time: too light and it can feel hard to control, too heavy and it can feel like hard work by the back nine.
Manufacturers now build whole clubs around this. PING’s G440 MAX HL driver, for example, combines a lighter back weight, a lightweight grip and the ALTA Quick shaft, offered at 38g or 45g, with a 46-inch length. PING says slower-swinging players in its testing gained about nine yards on average. That’s a manufacturer figure from its own testing, not an independent result.
Kick point and torque: weaker than their reputation
Kick point (or bend point) is where the shaft flexes most. Conventional wisdom says a lower kick point and a softer tip launch the ball higher with more spin, and PING’s broad guidance agrees. But PING’s shaft engineers told MyGolfSpy this year that the softer-tip-means-higher-launch rule only held roughly half the time in their testing, depending on the player.
Torque is how much the shaft twists, measured in degrees. Low-torque shafts feel firmer, and torque is often sold as a control spec. PING’s view is that torque mostly changes feel, with little measurable effect on average. Its testing also found higher-torque shafts tended to leave the face slightly more open at impact, which could suit a player whose miss is left rather than hurt them.
Stock or “made for” shafts
Stock shafts have a mixed reputation; PING’s engineers told MyGolfSpy that many are chosen mainly to hit a cost target. PING argues its own stock shafts are designed around its heads rather than picked as an afterthought, and that the head should do the big adjustments to ball flight, with the shaft used for fine-tuning. That’s a manufacturer’s position, but the order of priorities is sound: get the head, loft and length right before paying extra for an exotic shaft.
Choosing a shaft: chart first, launch monitor second
- Use the chart to narrow the field. If your driver speed is in the high 80s, start with regular and the lighter end of the range, then test either side.
- Don’t compare letters across brands. An S from one company isn’t an S from another. Compare like with like, or rely on the launch monitor.
- Try weight before flex. If the club feels whippy or hard to time, a heavier or lighter version of the same model may make more difference than a different letter.
- Judge by results, not feel alone. Look for a better strike pattern, tighter dispersion and sensible launch and spin, not just one big drive.
- Get fitted with your own swing in the room. Titleist, for instance, says a fitting typically takes 30–60 minutes per club category on a launch monitor. Ask whether shaft changes carry an upcharge before you start.
Sources
Spotted an error? Tell us and we will fix it. Our editorial standards.
