My dahon helios D7 came with a 7 speed freehub. the helios was updated to 2x7 and then 2x9 and is still on the original sora short cage derailleur. I swapped the wheels because I found a cheap old "new stock" set of Kinetix comp for £60...
Tern b7 seems to be free wheel.
isla bike uses 7 speed cassettes on 130 hub.
https://cdn.shopify.com/s/files/1/04...f?v=1630577985
If run a cassette with a shimano derrailleur, you can upgrade the cassette to 8 or 9 speed and swap the shifter only. I have run Sora short cages and Altus M310 (sora is more precise than m310) in the following config:
7 speed cassette with shimano twistgrip 7s
7 speed cassette with shimano alivio trigger 7s
7 speed cassette with shimano tourney dropbar 7s
8 speed cassette with shimano altus trigger 8s
9 speed cassette with shimano sora trigger 9s
9 speed cassette with shimano acera trigger 9s
9 speed cassette with shimano alivio trigger 9s
9 speed cassette with shimano sora dropbar 9s
I run the following cassettes:
7s 11-30 (sunrace)
8s 11-32 (Shimano altus)
9s 11-25 (shimano )
9s 11-34 (shimano sora) - 2T over spec for m310 and 4T over spec for sora short cage
9s 11-36 (sunrace) - 4T over spec for m310 and 6T over spec for sora short cage
9s 11-40 (sunrace) - 10T over spec for sora short cage (not tested with m310)