Originally Posted by
YankeeBike
I've read repeatedly that a small sprocket will cause a reduction in transmission efficiency, especially at very small sizes. My question is, is it the small size of the sprocket or the limited number of teeth that matters more? ....
It has to do with both.
The loss is related to the amount of angle that the links have to turn to run around the sprocket. Larger sprocket = less angle and shorter links = less angle, though it is difficult to find roller-link chain that's less than 1/4" pitch or so.
I remember seeing that gear setup in the print magazines at the time, but never saw any in real life.
I don't think I'd worry about the chainline efficiency so much as I'd wonder about the long-term reliability (especially since new parts probably aren't available now...).