TR brake rotors

["Edward Woods" <fogbro1@home.com>]

List,

What's the difference between TR3, TR4 and TR6 brake rotors (discs)?
Thickness? Diameter? Other?

I have a pile of them I'm trying to sort. About the only diff I can see is
that some are slightly greater (1/4" or so) in diameter.

Thanks,

Ed Woods