19mm is pretty standard for modern bmx bikes 22mm is odd but I come across them once in a while... I've never seen a 23.75 that I'm aware of.
I'm guessing you're felt could be that 23.75 because I've never actually measured the center hole for a one piece style crank chainwheel... I'm just guessing about that.
Your best bet would be to unassemble what you have and measure it with a set of calipers... you can find them pretty cheap at the big box stores... even the cheap ones are a great measuring tool to have for us bike guys. they take the guesswork out of everything.
Thanks for the reply. What you suggest is exactly what I did, but unfortunately not till after buying a 41T chainwheel that doesn't fit.
And you guessed is right, the Felt chainwheel does have a 23.75 mm center hole. Unfortunately I bought a 41T sprocket that only has a 19 mm center hole. But I noticed in the picture it had a spacer pressed into it's center, so I thought if I knocked it out it would fit. Wrong again. After knocking out the spacer, it's 22 mm. D@%n!t why does everything have to be so complicated.
What I'm finding out is locating a spicific size sprocket is difficult when you're picky. I want alloy. I want black, but now I'm willing to paint my own. I want a 23.75 mm center hole. I want 3 different sizes, 41, 42, 43.
So far I found a 40T, and I have the stock 44T. I wonder it I can get someone to bore the 41T I bought that doesn't fit, out the 23.75 mm? If not I found a 41T I can buy, but I'll have to paint it.
That's all I've been able to find. A 40T, a 41T, and a 44T which I don't need, and some even bigger ones. There just doesn't seem to be much verity.