Anyone with a 1 piece driveshaft? D I have a problem or is this normal?

[e30-323ti]

Will add my 2c even though it sounds like a wheel bearing issue (for now).

I've had no end of issues with a 1pc drive shaft in my 1JZ+E30 track car.
Have tried thin & thick wall tubes and 2.75"& 3" diameter tubes (length was 1100mm from memory).
All had horrific vibrations at slightly varied (high ~200kph) speeds.

Run up on a hoist at the drive shaft shop you could visually see the tube start to 'whip' or oscellate at speed.
This was something that couldn't be checked on their dynamic balancer as it would only do 4or5000rpm, when it started the 'whip' at ~6000prm (shaft).

In the end I tossed it and went to a modified JZA70 2pc, and is smooth as silk.
I've now moved the engine back ~400mm so will have another go with a 1pc being quite a bit shorter now.

[Jonb42]

I pulled the wheel hub. The bearing was toast and it looked like the weld that holds the section that the wheel bearing sits in to the carrier has started to crack. Half of it isn't there. I noticed this after cleaning it up with a wire wheel. I'm gonna have to swap this for my old cars. Unfortunately the car isn't movable and its 10 degrees f outside. I'm gonna be awfully cold for a hour or so. Lol. I'll update everyone after I install the new bearing and hopefully have a on. Thanks again

[Jonb42]

I would like to start by thanking everyone for your help. I got the problem resolved for now. I put the stock driveshaft and the vibration is gone. I think I know what I did wrong or where I went wrong. Wen I purchased the 1 piece I also purchased the adapters for the fron and rear flanges. I wasn't thinking about this but when I had to shorten the driveshaft I didn't bring the adapters in with the driveshaft. I'm thinking that because the driveshaft wasn't balanced with these on it threw the balance ever so slightly. I'm going to be bringing in the driveshaft with the couplers to confirm this sometime this week. But in any case the car is running very smooth. I will let everyone know if my theory is correct. They only thing that's making me ? It is the fact that I got the couplers and the driveshaft in 2 separate orders and there were no marks showing any specific alignment of these to the driveshaft. I'm thinking about just purchasing new rubber couplers for the oem driveshaft and seeing how these handle the torque of the new setup I have. What kind of luck does everyone else have with the oem rubbers? I haven't heard of any crazy horror stories as long as you keep your eye out for them dry rotting and don't ignore the fact that they do need to be replaced every so often. Opinions are appreciated. Thanks

[George]

In general, if your adapters offer even a little play of the shaft until you tighten it, you'll get misalignment => vibration