Spinning Wheel Ratio Calculator

Drive ratio from whorl and drive wheel diameters.

Drive wheel diameter (in)

Whorl diameter (in)

Treadle speed (RPM)

Target TPI

Tab to move between fields

Drive ratio

Flyer RPM660

Twists per minute660

Drafting speed (ft/min)9.2

Yarn output (yd/hr)183.3

Yarn Weight CategoryWorsted / Aran

How to Use This Calculator

Measure and enter your spinning wheel's drive wheel diameter in inches.
Measure the whorl (pulley) diameter in inches for the whorl you are currently using.
Enter your comfortable treadling speed in RPM (a relaxed pace is typically 50–80 RPM).
Enter your target TPI for the singles yarn.
Read the drive ratio and flyer RPM to understand how fast your flyer is spinning.
Use the drafting speed in ft/min output to calibrate how fast to draft fiber for your target TPI.

How the result changes with Whorl diameter (in)

Drive wheel diameter (in): Diameter of the large drive wheel in inches.
Whorl diameter (in): Diameter of the flyer whorl (pulley) in inches.
Treadle speed (RPM): How fast you treadle — comfortable pace is typically 50-80 RPM.
Target TPI: Desired twist per inch for your yarn.

Drive ratio: Ratio of drive wheel to whorl diameter (flyer turns per treadle turn).
Flyer RPM: Revolutions per minute of the flyer/bobbin.
Twists per minute: Number of twists inserted per minute at your treadle speed.
Drafting speed (ft/min): How fast you should draft fiber to achieve your target TPI.
Yarn output (yd/hr): Approximate yards of yarn produced per hour at sustained pace.

Identify Input Parameters
4 parameters
Drive wheel diameter (in) = 22, Whorl diameter (in) = 2, Treadle speed (RPM) = 60, Target TPI = 6 = 4 input(s) provided
Calculate Drive ratio
Drive ratio = driveWheelDiameter / whorlDiameter
11 = 11
Calculate Flyer RPM
Flyer RPM = treadleRpm * driveRatio
660 = 660
Calculate Twists per minute
660 = 660