So the cupped spring of the Strida does not have standard dimensions, this is really strange. It is maybe made according to Chinese standards
Coming back to the contact surfaces of the cupped spring, here is what you can find on the same website as the one of the catalogue:
I wonder also why washer 364 has a stange shape when used. Is it a flat washer when new or is it also a kind of cupped spring? In the first option, it looks like the steel is much too soft for the loads it has to stand…
