Fitting Updated

Shaft flex chart

There is no single shaft flex chart: each maker draws its own lines. In the 6 shaft charts below, from UST Mamiya and Mitsubishi, stiff starts anywhere from 81 to 91 mph of driver swing speed, and the same 85 mph swing reads R on UST Mamiya's LIN-Q M40X and S on Mitsubishi's TENSEI 1K Black. Type your speed and read each maker's own answer.

Your speed on each maker's chart

This is an example: a driver swing speed of 85 mph. Type your own speed and the answers below follow.

The flex each maker's chart gives at the speed typed above
ShaftFlex at 85 mph
UST Mamiya Helium NCT (lightweight)A or R
UST Mamiya LIN-Q M40X WhiteR
UST Mamiya Recoil Dart (iron shaft)F2 or F3
Mitsubishi TENSEI 1K Black 65, 75 and 85S
Mitsubishi TENSEI 1K Pro Blue 50R or S
Mitsubishi VANQUISH VV 4 (lightweight)R

Every chart, as its maker prints it

Driver swing speed in miles per hour, with the driver carry in yards where the maker prints one. A dash means the maker leaves that band empty for that shaft. Mitsubishi heads its top column ">106" on the TENSEI 1K Black and VANQUISH VV pages and "106+" on the TENSEI 1K Pro Blue page; on all three the column before it ends at 105 mph, so 106 mph is read here as the first speed of the top column.

Each maker's flexes by driver swing speed, from its own page
ShaftFlexes by driver swing speedStock on the clubs we cover
UST Mamiya Helium NCT (lightweight)
UST Mamiya's page, read 15 Oct
L: under 70 mph, carry under 175 yards
A: 70 to 85 mph, carry 175 to 210 yards
R: 80 to 95 mph, carry 200 to 240 yards
S: 90 to 105 mph, carry 225 to 260 yards
none
UST Mamiya LIN-Q M40X White
UST Mamiya's page, read 15 Oct
R: 80 to 95 mph, carry 200 to 240 yards
S: 90 to 105 mph, carry 225 to 260 yards
X: over 105 mph, carry over 260 yards
none
UST Mamiya Recoil Dart (iron shaft)
UST Mamiya's page, read 15 Oct
F2: 70 to 85 mph, carry 175 to 215 yards
F3: 80 to 95 mph, carry 200 to 240 yards
F4: 90 to 105 mph, carry 225 to 265 yards
PING G740 iron set, Srixon ZXi4 iron set, PING i540 iron set
Mitsubishi TENSEI 1K Black 65, 75 and 85
Mitsubishi's page, read 15 Oct
–: under 80 mph, carry under 210 yards
S: 81 to 90 mph, carry 210 to 239 yards
S or X: 91 to 105 mph, carry 240 to 259 yards
X or TX: 106 mph and over, carry 260 yards and over
PING G440 MAX fairway wood, PING G440 SFT fairway wood, PING G440 MAX driver, PING G440 SFT driver, Mizuno JPX ONE driver, PING G440 K driver
Mitsubishi TENSEI 1K Pro Blue 50
Mitsubishi's page, read 15 Oct
R: under 80 mph, carry under 210 yards
R or S: 81 to 90 mph, carry 210 to 239 yards
S: 91 to 105 mph, carry 240 to 259 yards
X or TX: 106 mph and over, carry 260 yards and over
none
Mitsubishi VANQUISH VV 4 (lightweight)
Mitsubishi's page, read 15 Oct
R2: under 80 mph, carry under 210 yards
R: 81 to 90 mph, carry 210 to 239 yards
S: 91 to 105 mph, carry 240 to 259 yards
X or TX: 106 mph and over, carry 260 yards and over
none

KBS says its MAX Graphite iron shaft is fitted by swing speed rather than flex, but its page prints no speeds in text; Mitsubishi's Kai'li charts list more flexes than columns, and its original VANQUISH chart does not say which row is which shaft weight, so all three are left out rather than guessed. Project X (True Temper), Aldila and Nippon print no swing speeds on the shaft pages we read on 15 Oct.

Iron shafts, by 7-iron speed

Callaway's iron fitting guide starts the flex from the head speed of a 7-iron, not the driver: Ladies under 60 mph, Light 60 to 70 mph, Regular 70 to 80 mph, Stiff 80 to 90 mph and X-Stiff 90 to 100 mph. A 7-iron swings slower than a driver, so these numbers sit lower than the driver charts above and cannot be read against them. (Callaway's guide, read 5 Oct.) UST Mamiya does it the other way round: it fits its Recoil Dart iron shaft by your driver speed, in the chart above.

Why the letters don't match

The flex letters are each maker's own. A regular from one maker can play like another's stiff, and some makers use their own codes:

So read the chart for the shaft you are actually buying, and use the flex letter only inside one maker's range. The senior flex guide explains what a softer, lighter shaft changes, steel vs graphite shafts lists every forgiving iron set's stock shafts, and the best driver shafts page compares the weight and flight of seven driver shafts.

Questions buyers ask

What flex shaft do I need for my swing speed?

Type your driver swing speed into the finder above and read each maker's flex for it. At 85 mph, for example, UST Mamiya's LIN-Q M40X chart says R and Mitsubishi's TENSEI 1K Black chart says S: the makers draw their lines in different places, so check the chart of the shaft you are buying.

What swing speed is regular flex?

In the charts here, regular runs from under 80 mph (Mitsubishi's TENSEI 1K Pro Blue 50) to 95 mph (UST Mamiya's LIN-Q M40X). Callaway's iron guide puts regular at 70 to 80 mph of 7-iron head speed, which is a different measurement from driver speed.

What swing speed is stiff flex?

Stiff starts at 81 to 91 mph of driver speed in these charts, depending on the shaft. Two Mitsubishi charts print both regular and stiff, or stiff and extra stiff, for one band: there the maker leaves the choice to a fitting.

I don't know my swing speed. What can I use instead?

UST Mamiya and Mitsubishi print a driver carry distance beside each speed band, and the chart lists them. A launch monitor in a shop or a fitting bay measures your speed in a few swings, and the fitting cost guide lists the free ones.

Is senior flex the same as A flex?

Usually: A, senior, lite and amateur name the same step below regular, and some makers use their own codes. UST Mamiya's Helium NCT chart, the one here that prints an A flex, puts it at 70 to 85 mph of driver speed and its L under 70. Srixon calls its R2 "Senior", and UST Mamiya's iron shafts use F2, F3 and F4. The senior flex guide explains what the softer, lighter shaft changes.