Driveshaft Tech
Changing driveline characteristics sometimes cause unexpected results. Here are some things to consider when modifying or changing your driveline. There are some critical calculations that you should be aware of and you will need the following information.
1. Tire height
2. Gear Ratio
3. Road Speed
This information gives you the driveshaft rotational speed. (RPM) of the output shaft. Now this factors into what is known as the Critical Speed of all spinning shafts. 4 factors affect the critical speed of a shaft.
1. Shaft RPM, see above
2. Shaft material type metal, aluminum, carbon fiber & different material strength
3. Shaft diameter
4. Shaft length
Why is this important? When a tube is suspended at each end and then made to spin, there is a critical speed where the shaft will begin to 'oscillate' which causes severe vibrations that you don't want to know about. I suggest you do your own research on CRITCAL SPEED, but here are some basics.
Use the link below to calculate the driveshaft's rpm based on maximum desired cruising speed
Then use this value to decide what type of driveshaft you will need to avoid the 'Critical Speed''. Different driveshaft manufacturer's calculate the critical speed of their driveshafts based on percentage above your calculated rpm's determined above. Several manufacturer's offer calculators to determine this. https://spicerparts.com/calculators/critical-speed-rpm-calculator