It does rust, Machined surfaces often rust, but that is partly due to it being polished with a pad with iron in it, of course as hyperextended stated depends where you live to how bad it can get. Also even if dust with iron on it gets layered onto stainless that can get damp will form a slight rust dust look. Point is it is not generally really Rusting, it is just a layer of dust or something that has polished the stainless that is put some iron particles then will form a slight layer of rust on stainless surfaces polished or not.
I agree with Neil, why should you have to put up with rust on the none swept part of the rotor on a nearly £17,000 bike ?
IT RUSTS BECAUSE THE DISC HAS HIGH IRON CONTENT!!! How hard is that to comprehend? Grease the fecking thing, spray it with WD40 or even silicone.Paint it, spit on it, wipe your............no dont do that, sperm is salty I have heard.
The term "Stainless steel" is a very broad category which describes many different alloys of, basically, iron, carbon, chromium and nickel, with other minor elements too. It refers to steels which RESIST corrosion, but are not totally immune to it. Most stainless steels will corrode to some extent, and will do so more rapidly in certain environments. Generally speaking, the physical properties of the most corrosion resistant grades will be inferior to the ones which corrode more readily ... as is the case with discs. My old jap bikes had stainless rotors and you needed to put in a request a couple of seconds in advance of actually needing the brakes to work if it was raining. They were always shiny though. The monster on the other hand, starts stopping as soon as you touch the lever, rain or shine. If your garage is heated intermittently then your corrosion could easily be the result of condensation. I'm not sure where this "iron content" thing comes from. All stainless steels are probably about 75% iron anyway.
