It's hard to find those, I've read about them. They are most prominent in the bicycles used for the "little 500" in Indiana's raceway every year. I keep an eye out for the hubs on Ebay, but a lot of them are old and I'd hate to use one but trash it the first time it malfunctions. The ones I speak of (and probably you too) are the "Bendix" rear hubs. I would definately buy one If I had the chance though, just to try it. I keep changing my mind about what sort of wheels I want to use, and it's driving me nuts. The Bendix hubs were my obsession a few weeks ago, when they seemed to be plentiful. I guess I could go to the next Little 500 and buy one off someone!