The Formula rear hub has one side threaded for fixed - with the reverse thread for a locknut, the other side is threaded for a freewheel, but I've used an old bottom bracket lockring, so I can use a fixed sprocket instead of a freewheel on that side. It's an old trick.
If you're not sure what I mean I can post a photo.
The Formula rear hub has one side threaded for fixed - with the reverse thread for a locknut, the other side is threaded for a freewheel, but I've used an old bottom bracket lockring, so I can use a fixed sprocket instead of a freewheel on that side. It's an old trick.
If you're not sure what I mean I can post a photo.