Bike chains aren't typically made from stainless steel because it's more expensive, harder to work with, and less durable under high stress, often leading to premature stretching or fracturing compared to specialized alloy steels, despite its rust resistance; standard steel chains, often plated or treated, offer a better balance of strength, wear resistance, and cost, with rust managed by lubrication. While some stainless options exist, they sacrifice performance or add significant cost for corrosion resistance, and even stainless can eventually wear or become contaminated.