…while others are for resin and sintered? Are they made of different stuff?

yup, discs from lower series brakes seems to be resin only so probably a different grade of steel or heat treatment

According to Shimano:
“What are the differences between the metal and resin disc brake pad compounds?

Metallic pad compounds offer greater braking power and more resistance to heat-induced fade.

Resin pad compounds offer better modulation and less noise.”

http://singletrackworld.com/forum/topic/shimano-xt-m785-slx-m675-brakes-what-pads

sintered = heat build up

Macavity – Member

According to Shimano:
“What are the differences between the metal and resin disc brake pad compounds?

Metallic pad compounds offer greater braking power and more resistance to heat-induced fade.

Resin pad compounds offer better modulation and less noise.”
Posted 17 minutes ago # Report-Post

You are answering a different question to the one that’s been asked , are the discs made of different stuff , not the pads

I assume the lower end discs are made of a softer metal but I have used sintered pads on them for many years with no problems .

Are you sure its the rotors they are talking about?

On the previous versions of Shimano brakes (M775 type ones) it wasn’t the brake rotor but the brake system that was recommended for resin or organic pads only.

This was to reduce heat build up in the mineral oil which doesn’t cope as well as DOT fluid.

If you don’t live somewhere which epic mountains then you are unlikely to build up enough heat to boil the fluid so maybe able to get away with running sintered if you really want to.

http://forums.mtbr.com/brake-time/ice-tech-rotors-vs-hs1-rotors-771669.html

http://cycle.shimano-eu.com/publish/content/global_cycle/en/nl/index/news_and_info/Velotech_Disc_Brake_Test.html

Are you sure its the rotors they are talking about?

Yes, some of the very cheap ones starting SM-RT5 and designated as resin pad only. M775 brakes were not listed as resin only AFAIK. The early Deore M525 were though.

The cheaper Shimano rotors aren’t hardened SS, so wear more quickly with sintered pads, hence Shimano label them as “resin only”.

My rotors definitely say resin only. (I run XT brakes but must have bought cheaper rotors). I’ve run them with sintered pads most of the time and a bike shop did recently tell me that they were a bit too smooth and I should consider filing the surface for more bite. Possibly a result of the sintered pads.

Macavity – why do you keep posting stuff that doesnt answer the original question?

The OP was not asking anything about icetech or pad compounds.

He is asking about NORMAL Shimano DISCS. The cheaper discs have “resin only” on them and the higher model ones don’t.

andyl

You are answering your own question.