This thread is intended to provide accurate factual information about 1 piece driveshafts regarding critical speed.

All subjectivity and opinions are not intended to be expressed here.

After reading all the discussion about critical speed and 1 piece drive shafts I have decided to research this topic further.

Critical Speed: The critical speed of a spinning shaft is described as the lowest speed which excites the shaft at it's natural frequency of vibration. This will cause the shaft to bend under the stress of vibration coupled with the centrifugal forces due to the rotation. In English, this means the shaft will vibrate very badly and possibly take a permanent bend (if not destroy the car in the process) as the critical speed is exceeded. If you use the calculator to predict the critical speed of a shaft, you can clearly

see that lighter materials with higher modulus of elasticity give higher critical speeds. So do larger diameter shafts with thinner material thicknesses. Unfortunately, there is a limit to the diameter of shaft you can put in the car, so stronger lighter materials were developed to make stronger and faster spinning shafts.

I have modified a multi-purpose calculator in Excel.

It calculates:

Tire Diameter

Tire Width

RPM at MPH per gear

MPH at RPM per gear

Driveshaft Tube Weight

Critical Speed

1/2 Critical Speed

Torsional Yeild

Max Drivshaft Speed

Added -> Driveshaft RPM at MPH

Graphs

Download Here

Host 1

****Updated host 1 link as of 11/29/2020

I hope this thread brings together useful information from the multiple threads on this subject.

Most people are aware of this calculator already.

http://www.wallaceracing.com/driveshaftspeed.htm#modulus

I have recreated all of these calculations and fixed some errors they had.

I also added many more calculations that you may find useful.

Mods: Could you fix this for .xls files?

Your file of 47.5 KB bytes exceeds the forum's limit of 1.0 KB for this filetype.

I would like to upload it directly to the site.

Maybe make this a sticky?

All subjectivity and opinions are not intended to be expressed here.

After reading all the discussion about critical speed and 1 piece drive shafts I have decided to research this topic further.

Critical Speed: The critical speed of a spinning shaft is described as the lowest speed which excites the shaft at it's natural frequency of vibration. This will cause the shaft to bend under the stress of vibration coupled with the centrifugal forces due to the rotation. In English, this means the shaft will vibrate very badly and possibly take a permanent bend (if not destroy the car in the process) as the critical speed is exceeded. If you use the calculator to predict the critical speed of a shaft, you can clearly

see that lighter materials with higher modulus of elasticity give higher critical speeds. So do larger diameter shafts with thinner material thicknesses. Unfortunately, there is a limit to the diameter of shaft you can put in the car, so stronger lighter materials were developed to make stronger and faster spinning shafts.

I have modified a multi-purpose calculator in Excel.

It calculates:

Tire Diameter

Tire Width

RPM at MPH per gear

MPH at RPM per gear

Driveshaft Tube Weight

Critical Speed

1/2 Critical Speed

Torsional Yeild

Max Drivshaft Speed

Added -> Driveshaft RPM at MPH

Graphs

Download Here

Host 1

****Updated host 1 link as of 11/29/2020

I hope this thread brings together useful information from the multiple threads on this subject.

Most people are aware of this calculator already.

http://www.wallaceracing.com/driveshaftspeed.htm#modulus

I have recreated all of these calculations and fixed some errors they had.

I also added many more calculations that you may find useful.

Mods: Could you fix this for .xls files?

Your file of 47.5 KB bytes exceeds the forum's limit of 1.0 KB for this filetype.

I would like to upload it directly to the site.

Maybe make this a sticky?

Last edited: