Hello,

I'm glad that I could be of some help.

I see at least 3 versions of the FF System on ebay and various bike sites. One is a single piece crank and I am very sure that its sprocket will not interchange with the 3 piece units because of the spline pitch, shape and hole diameter. There seem to be 2 versions of the 3 piece crank. The earlier systems such as mine have six spokes in the sprocket. The later versions have five spokes. The only detailed five spoke photo that I found on the web was from an expired (unsold) ebay listing. The spline count and shape appear the same as for the 6 spoke version, but the diameter is harder to know. The five spoke version may come as a single or double sprocket and I don't know the tooth counts. I would appreciate any additional information anyone might have.

Thanks,
Mike