i have been asked by someone to make some stainless brake discs for a trials bike..

does anyone know what spec stainless they are???

cheers

barry

didn't think any brake discs are stainless?
brake discs normally rust after a day or 2 of not being used. don't know about mototrbikes right enough

I don't know about stainless brake discs, but some years ago we fitted a stainless steel seal seat to a ships propellor shaft seal. The wear part of the seal was a material very similar to tufnol.
The stainless seat "picked up" and particles of stainless were embedded in the rubbing face the subsequent metal to metal contact wore multiple deep narrow grooves in the seat and seal face.

So in my opinion stainless discs will not be very good. The usual reason for using cast iron is that the carbon helps to lubricate the disc without making it too slippery

Stainles steel, or what appears to be stainless steel is commonly used for motorcycle discs
Exactly what grade though?

the one i have to copy is deffo stainless...

We made some wavy s/s brake discs for our racing moped (oi, stop laughing at the back). For a trials bike, and the same for our moped, as the disc speed is comparativly low and the amount of use it will see, we could just use any old grade of stainless we could find. In this application the fact it won't rust up was our biggest advantage. If I was making a disc for a 150mph race bike then no way would we make one.
So IMHO in this application, grade is not really important.

I've done a quick google on it but only found 1 reference. It was a patent on a rotor that had a skin of stainless steel on either side of an Aluminium core to make a light weight rotor. The patent suggested 304 or harder grade. Not too helpful to you but a nice idea.

Bike rotors are stainless which is why the pads are sintered brass. 420 stainless rotors with a 6061-T6 carrier is common. The centre is aluminium with a floating outer of stainless, never seen any with a skin of stainless over aluminium, I can't see how these would hold together.

The last time I messed around with bike disc's , they were made from `stainless iron' rather than stainless steel - so they were magnetic , and had very good corrosion resistance .
Back it the 70's a lot of jap discs were indeed stainless steel - maybe why they just didnt work in the rain ?

could be that the rain doesnt like you on a bike ???