Driveshaft 'weight' ?

[miller]

Wondering if anyone can educate me on a driveshaft I have.

Got it with other parts I picked up for my build. Don't even know if it will fit, yet. Haven't bothered measuring anything. It's 'about' the same size as a late 60s B model.

Question is, on the slip yoke end of the shaft, just aft of the U-joint, is a solid chunk of steel. One to one and a half inches thick, round, like a collar around the shaft, 6-7 inches in diameter.

What am I looking at? Any ideas. Or something I don't want any part of.

For my build, probably have a new shaft built, anyway...just curious.

 

[Meep-Meep]

That's called an inertia ring and its original purpose was to serve as a torsional damper (like a harmonic absorber found on your engine). The shaft is installed with the ring on the tranny end. Some cars had them and some didn't and I'm not exactly sure the criteria used to determine what got it and what didn't. I can guess gear ratio was a factor because at certain speeds there was noise associated with vibration.

 

[miller]

Appreciate that!