Can't seem to find any anywhere from any manufacturer… do they exist?

just file one off 🙂

Middleburn do 22 and 24 (on a one-piece guard/ring). Never seen 23.

Edit: I made a huge assumption that you wanted trials ring for some reason. Still never seen a 23t though.

Nope I've never seen 23, if TA don't do them, they don't exist!

I have to ask though… why!?

/Dons tin foil hat
It's all part of a global conspiracy. Bike companies don't like to make prime number chain rings as they last longer.

Very odd that no-one makes them… can't seem to find any 25 tooth ones either. Must be a conspiracy!!

why not dismantle an old cassette for a 23 tooth ring and drill it to fit?

no doubt you'll find some obscure titanium one from somewhere, Tune don't do them but i bet someone does. maybe even some vintage ones around

That is a good idea – could also get a 25 or any other odd sizes that way. Cheers.

Again… why?

I have looked at all the ratios I can get from different combinations of cassettes and chainrings, and i like the ratios I would get with a 23 tooth granny ring. Unfortunately it seems i'm not allowed to have one!

The fact that not even the custom folk like Boone seem to make one I wonder if there's an actual reason it wouldn't work very well. They do 20, 21, 22 and 24.

Yeah, maybe shifting wouldn't be good because of the odd number of teeth or something.
Where did you see a 21 tooth Boone listed?

Ask these guys?
Highpath Engineering

I wonder if there's an actual reason it wouldn't work very well. They do 20, 21, 22 and 24.

3 turns and your bike collapses into a black hole ??

highpath will make ANY size for you.

As will fibre lyte if you want some carbon bling!

EDIT: must type faster