Quite simply,these Disc Bolts are made out of material that are of the crappest quality,there's no other way to describe it.....it really is literally monkey metal.

I have taken all of mine off,spun them up in a pistol drill,wet & dry papered them till they were gleaming,coated them with ACF50,let them sit with a liberal ACF coating for a weekend then put them back on the wheels after gently mopping off the excess to stop any excess ACF "Fling" onto the surface of the Discs and within the week....speckling again. Just crap quality steel....monkey metal. So then I did it all again but painted them in silver Hammerite....speckling within the month and I don't ride in the wet. I think the metal is corroding anyway,because it is not pure enough. A kind of corroding from inside out,it does happen alot. Happened on my Dad's Ford Focus whichwas 3 years old,it needed new front lower wishbones because of this,they were made in Spain too,funnily enough. It's basically costcutting.

Cheers - Stim