I think given the way Bird “do” travel, I don’t think you’d really need an AM9 with more than 150mm?
I have a lot of faith in them, I think they try to design bikes to work really well for their intended use (they work pretty bloody great everywhere) if that means they’re best suited to 275 then it’s 275. Leave it to SC to make a two versions of the same bike with different wheel sizes.
The implication is that they’ve got
AM9 – race;
Aeris160 – park/alps/big mountain;
120(and now Aether) – play/trail.
I have used mine for all 3, so they are no one trick pony. A full n+1 stable is still the money no object ideal though.
While I like SC as a brand and they are nice bikes, no idea which one I want. Plus they do a Volkswagen and jump half a category upwards at each new iteration.