Driveshaft Critical Speed Calculator

Calculate the critical speed at which a driveshaft will experience dangerous resonant vibration.

Tube Outside Diameter (inches)

Tube Wall Thickness (inches)

Shaft Length (inches) Center-to-center of U-joints

Tube Material

Operating Parameters

Trans Gear Ratio (1st)

Max Engine RPM

Common Driveshaft Specs

Tube Size	Wall	Max Length*
2.5" Steel	0.065"	~42"
3.0" Steel	0.083"	~54"
3.5" Steel	0.083"	~65"
4.0" Aluminum	0.125"	~72"
3.5" Carbon	0.110"	~80"

*Approximate max length at 7000 RPM driveshaft speed with 15% safety margin