shaft-flex-guide

Golf shaft flex recommendation by swing speed. Get instant, data-backed shaft flex and weight suggestions for driver and irons based on club head speed and swing tempo.

For full charts and fitting guides, visit GolfLaunchLab:

• Golf Shaft Flex Chart
• Golf Swing Speed Chart
• Golf Club Distance Chart

Installation

Python (pip)

pip install shaft-flex-guide

JavaScript (npm)

npm install shaft-flex-guide

Python Usage

from shaft_flex_guide import recommend_flex, get_full_recommendation

# Single club recommendation
result = recommend_flex(swing_speed=95, club_type="driver", tempo="medium")

print(result["recommended_flex"])          # "S"
print(result["flex_label"])                # "Stiff (S)"
print(result["shaft_weight_range_grams"])  # "55-70g graphite"
print(result["explanation"])
# "At 95 mph with medium tempo, a Stiff (S) flex driver shaft will give you
#  the best combination of control and launch."

# Iron recommendation
iron_result = recommend_flex(swing_speed=75, club_type="iron", tempo="fast")
print(iron_result["recommended_flex"])     # "R/S" shifted to "S"

# Comprehensive driver + iron recommendation
full = get_full_recommendation(driver_speed=100, tempo="medium")
print(full["summary"])
# "Driver: S flex (55-70g graphite); Irons: S flex (85-105g steel/graphite)"

print(full["driver"]["explanation"])
print(full["iron"]["explanation"])

# Provide explicit iron speed
full2 = get_full_recommendation(driver_speed=100, iron_speed=78, tempo="slow")
print(full2["summary"])

Parameters

recommend_flex(swing_speed, club_type="driver", tempo="medium")

| Parameter | Type | Values | Description | |-----------|------|--------|-------------| | swing_speed | float | any | Club head speed in mph | | club_type | str | "driver", "iron" | Which club (default: "driver") | | tempo | str | "slow", "medium", "fast" | Swing tempo (default: "medium") |

Returns a dict with: recommended_flex, flex_label, flex_range, shaft_weight_range_grams, explanation.

get_full_recommendation(driver_speed, iron_speed=None, tempo="medium")

| Parameter | Type | Values | Description | |-----------|------|--------|-------------| | driver_speed | float | any | Driver head speed in mph | | iron_speed | float or None | any | 7-iron speed in mph (estimated as ~78% of driver if omitted) | | tempo | str | "slow", "medium", "fast" | Swing tempo (default: "medium") |

Returns a dict with: driver (recommend_flex result), iron (recommend_flex result), summary.

JavaScript Usage

const { recommendFlex, getFullRecommendation } = require("shaft-flex-guide");

// Single club recommendation
const result = recommendFlex(95, "driver", "medium");

console.log(result.recommended_flex);         // "S"
console.log(result.flex_label);               // "Stiff (S)"
console.log(result.shaft_weight_range_grams); // "55-70g graphite"
console.log(result.explanation);
// "At 95 mph with medium tempo, a Stiff (S) flex driver shaft will give you
//  the best combination of control and launch."

// Fast-tempo iron recommendation
const ironResult = recommendFlex(75, "iron", "fast");
console.log(ironResult.recommended_flex); // "S" (shifted from R/S due to fast tempo)

// Comprehensive recommendation
const full = getFullRecommendation(100, null, "medium");
console.log(full.summary);
// "Driver: S flex (55-70g graphite); Irons: S flex (85-105g steel/graphite)"

// Provide explicit iron speed
const full2 = getFullRecommendation(100, 78, "slow");
console.log(full2.driver.recommended_flex); // "R" (S shifted softer by slow tempo)
console.log(full2.iron.recommended_flex);   // "R/S"

Flex Reference

| Driver Speed (mph) | Flex | Label | |---|---|---| | Under 60 | L | Ladies | | 60–74 | A | Senior/Ladies | | 75–94 | R | Regular | | 95–104 | S | Stiff | | 105–114 | X | Extra Stiff | | 115+ | TX | Tour Extra Stiff |

Tempo adjustments shift one flex stiffer (fast) or softer (slow).

For the full interactive chart, see golf-shaft-flex-chart on GolfLaunchLab.

Related Resources

• Golf Shaft Flex Chart — full flex guide with visuals
• Golf Swing Speed Chart — speed benchmarks by handicap and age
• Golf Club Distance Chart — expected distances by club and swing speed

License

MIT License. Copyright 2026 GolfLaunchLab.