can brake rotors be machined

[firedan]

Can the brake rotors on a bike be turned like a cars?  If so, how many times before they are too thin?

[scratch]

The front one, no. The rear, dunno, probably not. Japanese typically use a hardened steel, which if you grind, removes the hardening.

[The Buddha]

I thought rotors were mild steel... of course the machining and finishing process puts a decent amount of work hardening into them...
Cool.
Srinath.

[JamesG]

They are homogenous mild stainless.  They have a minimum thickness of 4mm or so. They start at only 5~6mm so bike rotors can't be turned, but they can be flattened, but that can be more expensive than picking up a new(er) one off fleaBay...

[The Buddha]

Stainless... why do they rust in like 2 days in the rain then... Yea there is stainless that does rust... but still its rather quick for stainless to rust.
Cool.
Srinath.

[JamesG]

I guess you've never seen an iron rotor left out in the rain overnight...

[The Buddha]

OK I have and the GS ones are just as bad... however I guess we end up with some steel in the surface from the pads on these things... dont we.
Cool.
Srinath.

[70 Cam Guy]

Stainless... why do they rust in like 2 days in the rain then... Yea there is stainless that does rust... but still its rather quick for stainless to rust.
Cool.
Srinath.

Some stainless can rust.  Many many different grades.  Some stainless is even magnetic

[2Twin]

I needed another one for the rear of mine. I got a re-manufactured one(Skimmed one basically) for less than 100 Australian dollars. It was from a Across 250 though which is the same as the GS. Planet discs did them. I believe they are the only ones in Aus that can do it though. The catch is that they are not legal anymore (race use only) even though they are thicker than the minimum amount. I am pretty sure he said he could do the fronts as well or replace the disc and re- use the centre hub bit.

All in all I think it is cheaper to get one from a wrecker or ebay. I couldnt find any good ones from the wreckers here or ebay when I needed it and couldnt have the bike off the road for long.

[luke1645]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=35601&item=7900184781&rd=1

[Lars]

The stainless steel thing is funny. My brake disc starts to rust 1 hour after it's put in the rain. After 1 night it can be completely brown.
I think the thickness of a new disc is 4.1 or 4.2 mm. They are extremely thin to begin with. Mine still isn't worn down after 44000 km though.