Gear Calculator

Gear Ratio / RPM / Speed Calculator

Determine Speed

Stock Tire Size:
width (mm):
profile (%):
diameter (in):
circumference (in):
adjustment (%):
Adjusted circ. (in):

Engine Speed:
RPM:
Gear Ratio:
Gear Ratio:
Final Drive:
Final drive:

Speed (mph) is:

Determine RPM

Stock Tire Size:
width (mm):
profile (%):
diameter (in):
circumference (in):
adjustment (%):
Adjusted circ. (in):

Wheel Speed:
Speed (mph):
Gear Ratio:
Gear Ratio:
Final Drive:
Final drive:

RPM is:

Determine Ratio

Stock Tire Size:
width (mm):
profile (%):
diameter (in):
circumference (in):
adjustment (%):
Adjusted circ. (in):

Wheel Speed:
Speed (mph):
Engine Speed:
RPM:
Final Drive:
Final drive:

Gear Ratio is:

Determine Speed: Use this calculator when you know your gearing and want to find your Speed at a given RPM

Determine RPM: Use this calculator when you know your gearing and want to find your RPM at a given speed

Determine Ratio: Use this calculator when you know your final drive, but want to find your Gear Ratio for a given RPM & speed.

Note: The circumference of the tire is computed for an ideal circle for the given tire dimensions.
You can use the "adjustment (%)" to raise or lower this by a percentage as you see appropriate

B5 S4 6-speed gearing is:		VW 1.8T trannys coded: EBQ, EMT, EGX, FBW
Gear Ratios:	Manual (Automatic)	Manual
1st	3.500:1 (3.665:1)	3.300
2nd	1.889:1 (1.999:1)	1.944
3rd	1.231:1 (1.407:1)	1.308
4th	0.967:1 (1.000:1)	1.029
5th	0.806:1 (0.742:1)	0.837
6th	0.684:1 (----)
Reverse	3.455:1 (4.096:1)
Final Drive	4.111:1 (3.511:1)	3.938

The above is the S4 (6-speed manual) gearing (RPM vs Speed) per data logging using APR's ECU Explorer. The bold areas are the actual datapoints logged, whereas the thin lines is the linear trendline with 0-intercept.