Large flakes of rust? Coming off rear breaks

I was washing my truck and as I was spraying down the back Rims I noticed a bunch of huge flakes running down the driveway with the water. This happened with both the back tires. Looks like rust maybe?Anyone else have this happen?

 

Mine did it. I just re-painted the drums when I had the wheels off.

 

Yeah it looks like the black paint is flaking off with the rust underneath it. Is it normal for this to happen?

 

Do you live close to the coast?

 

Nope. And I don't drive through water or mud. Wash it 1 or twice a month. Keep it in the garage. Not even 2 years old yet. Wondering if it is just a bad paint job on them.

 

Normal, all drums do that.

Most drums are cast iron, will take forever for rust to eat those.

 

Cool. Wasn't sure it it was going to give me problems down the road. I won't worry about it for now. May look into painting them sometime later. Thanks