Originally Posted by 6USMC6
Stainless steels have chromium in them (helps to make them "stainless") and the better stainless has molybdenum for toughness.
Chrome Moly Steel (41XX) is a low alloy steel
with excellent strength, harden-ability and welding characteristics.
Stainless steel, although it does contain both chrome and molybdenum is not chrome moly. Its strength characteristics for primary structure are... lacking.
The yield strength of stainless is generally 1/2 or less of its ultimate strength.
For chrome moly it is generally 2/3 to 3/4.
This means stainless will bend long before it breaks. It also doesnt work harden very well. We avoid the use of stainless in aircraft structures like the plague. It has nasty habits, especially over time and when exposed to certain chemicals.
Stainless also tends to pull horribly when welded. I would hate to imagine the poor bugger who had to design a stainless steel welded frame and account for how much it might or might not pull...
For frying pans, cutlery and industrial use, stainless is great, but for primary structure... yikes!
I've also been impressed with KTM's use of aluminium hardware in steel structure. Yes it stops the steel from corroding, but then the bolt corrodes and breaks. Maybe they've changed this over the years? Not worth the weight saving in my opinion.