Originally Posted by Duragrouch

Agreed. And while there may not be huge difference in wear with slight reduction in chainring size, I'll bet there is more in going from 13 or 12, to 11, and with a further reduction to 9. A consideration, as the the only way I could get by with a 16"/349 wheel (Brompton, 2024 Dahon Curl, et al) with external-only gearing (and not a monstrous chainring), is a 9 high in back.

11T high was not a challenge, even my old junky brand-x 7-speed freehub accepts that. 10T or 9T, on the other hand, requires a newer special freehub.