Originally Posted by
Broctoon
Galvanized (zinc plated) hardware is the cheapest and shortest lasting.
Cadmium plated, which has sort of a bright yellow finish, is next up.
Stainless, the most expensive stuff, tends to be hardest and is usually pretty tough too. But not all stainless steels are the same.
Anytime you see a bright, shiny silver finish on a cheap bike, it’s probably chrome plating over mild steel, and it will fail easily.
If you find hardware classified “Grade 8” it will be tougher than lesser or ungraded stuff. It might also be made to tighter tolerances, but I’m not sure about that.
True hot dip galvanized and zinc electro plated are not the same animal. How it lasts will depend on the fastener underneath and the process used. A hot dip galvanized grade 5 bolt would be strong and rust protected. A Gr2 electro plated wouldn't.
Grade 8 or the metric equivalent 10.9 really have no need on nearly any bicycle fastener.
nearly all SS fasteners a consumer is going to buy off a local shelf will be 18-8 302 or 304SS