I have a chain minder / watcher thing on my seat tube that helps guide the chain onto my granny gear. I'm dropping from 42 to 26 right now and the plastic shows some wear so I assume it's working from time to time.
My question is do they make a ring or a granny with a ring that would do the same thing? It wouldn’t be fixed to the frame but would rotate with the chain rings. Something like a bash guard on the outside but on the inside. It seems to me something larger than the granny traveling at the same speed and completely surrounding the granny with a slight taper / conical would bring the chain into place better.
I have searched around for something like this and am about to fire up the lathe and make one to find out as I haven't seen one for sale. Or am I missing something as to why it won't work?