Floating brake rotors...

[dougie]

I have always understood the reasons for two piece "floating" brake rotors to be as a help heat expansion to avoid warpage, and alignment with brake pads.
A friend's rice rocket track bike has developed a lot of play in rotation. You can lock the brakes, rock the bike back and forth, and hear the carrier, buttons, and disc hitting each other. Moving the disc by hand, you can see a good 1/16" back and forth play.
How can that be OK? Laying on the brakes hard causes these parts to hit, probably increasing the clearance over time and I wonder if one day .
Am I missing something? Anyone know real stuff about this?
I know most of our bikes don't have "floaters", but thought I would ask as visiting friends in the hospital is a PITA.

[Major Softie]

My Oilhead has stock floaters, and, with 60k miles on them, they have gotten pretty rattly on rough pavement, but I haven't noticed any rocking with the brake on. There are newer designs with some kind of springs in the carrier/disc interface to keep the rattling down.

I guess, like anything else, it's all a matter of degree: some rattling does not mean there's a problem, but obviously there would be a point where it's simply too worn. Your buddy's bike sounds too worn to me, but I don't know what the actual "spec" is.

[angileena]

I believe ZM was at least partially speaking tongue-in-cheek.

My first hint was when he said "you westerners," as he lives at least a few hundred miles further west than Chuey.