Hollowspoke Turbo wheel will not balance

[paulburrell]

A mate of mine has a 996 turbo and when changing tyres recently found that one of the front wheels would not balance, however the fitters tried to do it. He took said wheel to another fitter and the problem was the same. The wheel is as straight as a die. He has been told that it's almost as if there's a liquid in the body of the wheel that moves around and makes balancing the rim impossible. Anyone here ever come across such a phenomena and if so is there a cure or should the wheel just be binned??

[phelix]

If the wheel was refurbished it's possible that when the valve was removed blasting media or liquid from one of the baths/rinses got into the hollow portion of the wheel and stayed there. The tyre would need to removed as would the valve and then the wheel "drained". The spokes are hollow as is the portion of the rim that the valve goes through. That's why these wheels have special metal valves.

Note this info is all from the 993tt wheels but I believe the 996tt wheels to be the same.

[BliarOut]

I used to balance the large rolls that you get in printing presses and occasionally you would get one that was a right sod to do. It was usually due to inconsistencies in the casting process. You would put the correct weight on and the imbalance would just move

To get to the bottom of it the tyre's gonna have to come off again. I would try to balance the wheel minus the tyre to see if it can be bought in balance. If it can't then there's probably a casting imperfection, or liquid as they say.... That would be unusual though, if it got in, it should be able to get out.

Has he had any steering vibration before that indicated that the last tyre was running out of balance?

Some cylinders are just an arse to balance.