Originally Posted by
JohnDThompson
TA made 27T rings for the "Cyclotouriste" crank; my wife has one on her bike. I don't know if they're still made. TA also used to make custom rings in any tooth count; mostly very large, often used for those land speed record attempts. I don't know if they still offer that service.
Thanks for the info.
Given current CAM capabilities it would be straightforward for someone to make one from flat plate.
I recall that there was a program available from the IHPVA that would print a pattern for a chainring of any random tooth count. It was up to the user to print this out, glue it to a sheet of aluminum, then drill and file until done. That’s how they did it in the ‘80’s.