[Gustav]

So they are a brass alloy,i've been puzzling about this,i think they must be a brass alloy with a fair bit of Fe content?
They are attracted to my 7xl rotor but the force is much weaker than with steel,the brass rods i have here aren't attracted at all.

I think brass may be too hard anyway for the Rc4wd if they're only 6061,i'd use stock idlers with them unless there are some aluminium ones.

EDit:Ok i found out high strength brass has iron content for strength,just a few % so that explains the weak attraction to the magnet,unless it's an aluminum bronze,that has all sorts of stuff in it.So my brass bars are just copper and zinc i guess.