biopace rings
Somewhere in Sheldon Brown's stuff on-line he says that contrary to what one might guess, biopace rings are perfectly useable for fixed gear.
I have a junky MTB that I converted and put on a 42 tooth biopace just to see. At least with this set up, there is no way to get the chain to be acceptably tight throughout the rotation of the front ring. With it as tight as possible at one point, it will have far too much slack at another.
Anyone else play with this? Is it perhaps less of a problem with a larger chainring?
jim