Rusty Rotors, but not on a Spyder

[BLUEKNIGHT911]

I have owned to many cars to have kept track ….. if they weren't driven regularly - all the rotors would show some amount of rust, and some did it way more quickly than others ….. None of my Spyders have EVER exhibited any signs of rust at any time..... even if left in an un-heated garage for years …. Does anyone know Why ???? …. Ron do you know why this is ??? ...…….thanks … Mike hyea:

 

[JayBros]

I offer that it's the quality of the steel the cage rotors are made of.

 

[Chupaca]

Materials....

Due to the thickness and heat treatment . One reason you can not re surface them unlike the automobile discs. :thumbup:

 

[Grandpot]

Most car rotors are a malleable cast iron. Spyder rotors are a steel alloy.

 

[Hypurone]

High stainless content in the Spyder rotors. Motorcycles have high stainless content rotors to help combat rusting and shed heat quicker... At least for as long as I have been riding (1972)

 

[PinkRosePetal]

I'm with Grandpot. Car discs are normally cast iron, though better quality ones do contain some chromium. Cast iron rusts very quickly - if you clean cast iron in warm detergent water to degrease it, it'll rust in seconds.

Spyder discs are a grade of stainless steel so resistant to rusting - though they still can if air is excluded from the surface as in washing the bike and storing it with water between the pad and the disc. For info, stainless steel is poor conductor of heat so good disc ventilation is required.

However, there's another reason. Surface water from our roads eventually ends up in the sea via our drains, streams and rivers and some years ago copper and it's alloys were removed from car brake pads because copper is poisonous to aquatic animals, especially molluscs. (Hence its use as an antifoul medium on boat hulls.) Brake pads need a heat conductor to conduct the heat from the pad to the caliper and on to the car structure and in the absence of copper or its alloys iron was used. Though pad materials have moved on in their composition, many brake pads materials still contain iron and although the cast iron disc surface rusts, pitting can also occur in a short time if the pad containing iron is in contact with a disc for any length of time in a damp situation. It's not uncommon to have a pad shaped corrosion mark on a disc, even overnight.

However, motorcycles are exempt from the no copper rule for some reason so pad to disc corrosion is less common.