

Yeah, try riding a folding bike with small wheels, you wobble a lot more.
It’s not about the magnitude of the rotational inertia (which is roughly the same or maybe a bit higher on larger wheels that are probably heavier), it’s about the center of the gyroscopic effect. It’s at a greater height if you have big wheels, and closer to the ground if you have small ones.












You can order those directly from china via the big resalers like AliExpress or temu.
You’re still giving a cut to a big Amazon like company, but even when you buy things like phone cases locally, the local shops probably just brought it from one of the big resalers anyway.