What causes this on rotors?

[02zx9r rev2]

At a stoplight today, and was looking at this ladies rotors and was wondering what cause this? My rotors will have surface rust on them from sitting for a few days but then once I start driving it goes away.

This looks like it is pitted or is that brake pad material that has transferred onto the rotor?

 

[MSCH]

humidity. brake lining removes it on the first brake application.

 

[Rand]

Pad slap and no maintenance?
looks like the pad isnt really hitting half the rotor and some minor grooving.

Could be salt air related? not sure.

 

[dippschtick]

Cheap aftermarket junk?
They look pitted.

 

[Astro14]

Even good rotors will pit if they sit for a long time.

 

[vavavroom]

Looks almost damascened if you just squint hard enough.

 

[Kira]

I echo post #4.

 

[02zx9r rev2]

humidity. brake lining removes it on the first brake application.

Well this was at a stoplight coming off the highway. I would think that would have come off by the time you were to leave where you are, get on highway, and take an exit and then come to a stoplight

 

[slacktide_bitog]

If that's rust, then it could be bad caliper, as the piston might be stuck

 

[02zx9r rev2]

I was just wondering is all. I’ve seen rotors rusted on the vanes and hats, but it looked like it was pitted and rusted.

Not sure if this was original rotors on her Audi, I didn’t talk to the older lady driving it. Just seen it at a stop light and was like hmm, let me take a picture and see if anyone can tell me what this is or what causes this.

I appreciate the responses

 

[02zx9r rev2]

I took the picture through my window with 13% tint. Didn’t want to seem so obvious. I’m sure if window was rolled down would be better picture

I would assume it would make some type of noise so maybe she knows and thinks it’s normal???

 

[BMWTurboDzl]

At a stoplight today, and was looking at this ladies rotors and was wondering what cause this? My rotors will have surface rust on them from sitting for a few days but then once I start driving it goes away.

This looks like it is pitted or is that brake pad material that has transferred onto the rotor?

The hat (2-piece aluminum) and vans look almost new so perhaps its a quality control issue. Otherwise saltwater. It is a NE car after all.

 

[atikovi]

Car sitting for months at a time. Rotors don't rust away like that in just a few weeks.

 

[KrisZ]

This is pitting left from rust due to the vehicle sitting outside, likely for few months. Totally normal, but usually needs new rotors.

 

[Audiman]

I see this all the time, mainly A1, A3, and Q3. It’s usually on cars that see a lot of around town driving that mainly uses the front brakes.

Low quality brake disc material is partially to blame along side the usage type.