Written ByJamieA shaft flex chart turns your driver clubhead speed, how fast the head is moving just before it meets the ball, into a flex letter.
A golf shaft flex chart by swing speed gives a starting range, because maker bands overlap and differ. UST Mamiya’s R band runs 80 to 95 mph and its S band 90 to 105, so a 92 mph swing sits in both. Testing or a fitting settles what a chart cannot.
The catch is that shaft makers do not use the same bands, so one swing can be Regular or Stiff on UST Mamiya’s scale and X on the guide for one Mitsubishi shaft.
Golf shaft flex chart by swing speed
This table is Golfer Geeks’ starting point, the same bands the site’s driver and iron guides use. No maker publishes it as an official chart, and no industry standard sets it.
| Driver clubhead speed | Where to start |
|---|---|
| Under 70 mph | L (Ladies) |
| 70 to 80 mph | A (Senior) |
| 80 to 95 mph | R (Regular) |
| 95 to 105 mph | S (Stiff) |
| Over 105 mph | X (Extra Stiff) |
Between 90 and 105 mph, UST Mamiya’s R and S bands overlap from 90 to 95 and the Kai’li White 60 g guide moves to X at 91. If your speed sits near the edge of a band, test the flex on each side or get fit.
What each maker’s own chart says
Three makers’ pages used here publish mph bands. Shown separately, they disagree.
UST Mamiya. The Helium NCT and dRVR wood shaft pages both list L under 70 mph, A at 70 to 85, R at 80 to 95, and S at 90 to 105 (UST Mamiya’s product pages). A and R share 80 to 85, and R and S share 90 to 95.
Mitsubishi. The Kai’li White 60 g row of the fit guide puts under 80 mph in R, 81 to 90 in S, 91 to 105 in X, and over 106 in X or TX. The 70 g and 80 g rows sit a step stiffer at the same speeds. The guide carries a note that the guide is “for reference only” and that the maker recommends a professional fitter (Mitsubishi’s Kai’li White page). Mitsubishi describes Kai’li White as a low-launch, low-spin shaft, so read it as an example of the spread.
TaylorMade. The custom shaft booklet sorts its driver and fairway shafts into six average-clubhead-speed groups: under 72, 72 to 81, 82 to 92, 93 to 102, 103 to 109, and 110+ mph (TaylorMade’s custom shaft booklet). The booklet also tells fitters to consider angle of attack alongside swing speed.
Put side by side, a 91 to 95 mph swing is R or S for UST Mamiya and X for the Kai’li White 60 g. Those are different shafts, an ultra-light UST shaft against a low-launch, low-spin Mitsubishi shaft, so neither maker is wrong. It is the same speed mapped to different letters by different scales.
Callaway’s driver buying guide states the principle without mph bands: slower swing speeds benefit from more flex, and faster swings require less.
Why the same letter means different things
There is no standard for flex. A Club Champion fitting blog says there is “no 'standard’ for shaft flex/profile” and that “A stiff shaft from OEM A will be decidedly different in kick point and other details than a stiff shaft from OEM B” (Club Champion).
The names do not line up either. UST Mamiya uses L, A, R and S, and its Recoil iron shafts add an F0 to F4 scale. PING’s G430 Max driver page lists Soft Regular, Regular, Stiff and X-Stiff across its shafts, and 5.5, 6.0 and 6.5 on a Project X HZRDUS shaft. Mitsubishi’s online fit tool offers L, A/R3, R2, R, S, X and TX.
That is as far as the evidence goes on what a 5.5 flex shaft means. PING’s page lists 5.5, 6.0 and 6.5 as the flex options on that Project X shaft. Those numbers sit on a different scale from the letters, and this article has no maker conversion between the two, so a conversion table here would be false precision. For one data point, the spec block in the Cobra OPTM Max K driver review lists its Project X 6.0 shaft as Stiff.
How to find your driver swing speed
The direct way to get your driver swing speed is a launch monitor. Driver clubhead speed is measured in mph, and TrackMan defines club speed as the speed of the club head’s geometric center just prior to first contact (TrackMan’s club-speed page).
If you have never been measured, one session gives you the number the table above needs.
Where the average golfer lands
TrackMan’s published Combine averages for male amateur driver club speed are 110 mph for scratch or better, 101 for a 5 handicap, 95 for a 10 handicap, 94 for the average golfer at 14.5, and 92 for the bogey golfer. For female amateurs they are 90 for scratch or better, 87 for a 5 handicap, 83 for a 10 handicap, and 79 for a 15 handicap. TrackMan does not state its sample or method on that page, so treat these as published averages.
Placed against the maker bands, 92 to 95 mph sits inside UST Mamiya’s R band, inside its overlapping S band, and inside the Kai’li White 60 g X band. Those are different shafts, so the point is narrow. A golfer at the published average is in the range where the makers’ bands overlap and disagree.
For the women’s figures, take UST Mamiya’s bands. 79 mph falls in A, 83 in both A and R, 87 in R, and 90 in both R and S. The letter depends on the maker there too.
Senior flex vs regular flex
Senior sits below Regular in the starting-point table. UST Mamiya has no Senior label; its A band runs 70 to 85 mph and its R band 80 to 95, so an 80 to 85 mph swing appears in both. In that overlap, testing decides.
Is Senior flex only for older golfers? The maker bands in this article are keyed to swing speed and say nothing about age. My beginner drivers guide says a Senior flex shaft should do the trick for a driver swing under 80 mph, and the table above sets its lower edge at 70.
The letter is a rough label, so check the band the maker publishes for that shaft. For the other driver decision that comes up at the same time, see choosing driver loft.
What about irons
This article uses no maker-published speed bands for steel iron shafts, so no iron chart is printed here. UST Mamiya’s Recoil ESX graphite iron shaft page (a discontinued model) keys its flexes to driver swing speed, with the F3 step at 80 to 95 mph.
In my guide to choosing irons for beginners, I recommend regular flex for most beginners. Shaft material, graphite versus steel, is a separate decision covered in graphite vs steel shafts.
When a chart is not enough
A chart is not enough on its own, and the makers say so. Mitsubishi’s fit guide carries its reference-only note and recommends a professional fitter, and True Temper’s FAQ says the company cannot fit a golfer by phone or email and that a golfer should see a professional fitter. TaylorMade’s booklet asks fitters to consider angle of attack alongside speed. Speed is one input among several.
My advice for a true beginner is blunter than any chart: do not get fit for clubs, do get lessons, and buy something with a regular shaft off the rack. For a faster or more experienced swing, how to get fitted for golf clubs explains the process. The guide to the best beginner golf clubs covers the rest of the bag.
Shaft flex questions
How do you determine what shaft flex you need?
A starting shaft flex comes from measuring driver clubhead speed in mph with a launch monitor, then reading that speed against a chart. Between 90 and 105 mph the makers’ bands overlap, so a speed near the edge of a band is worth testing in both flexes.
What swing speed needs a stiff shaft?
The swing speed that needs a stiff shaft is not agreed: UST Mamiya puts S at 90 to 105 mph and the Kai’li White 60 g guide puts S at 81 to 90. Golfer Geeks’ starting point for Stiff is a driver swing of 95 to 105 mph, as in the mid-handicap drivers guide.
Is S stiff or senior?
On UST Mamiya’s scale, S is a fast-swing band at 90 to 105 mph, well above its A band at 70 to 85, so S and senior sit at different ends of the range. Golfer Geeks’ starting point puts Senior at 70 to 80 mph, and none of the maker pages cited here define Senior as a band of its own.
What does a 5.5 flex shaft mean?
A 5.5 flex is one of the flex options listed on PING’s page for a Project X HZRDUS shaft, alongside 6.0 and 6.5. Those numbers sit on a different scale from letter codes, and this page uses no maker conversion. The Project X 6.0 in the Cobra OPTM Max K driver review is listed as Stiff.
What shaft flex do I need if I don’t know my swing speed?
A golfer who does not know their swing speed can treat the starting-point table as a guess. The Golfer Geeks advice for a true beginner is regular flex off the rack and lessons before a fitting. Otherwise, one launch-monitor reading turns the guess into a number you can read against any shaft flex chart.