Skyhawk172

I searched the forums trying to get a understanding on why the rotors on my car 2009 Turbo Carrera has small ridges on the face I always thought rotors where suppose to be smooth




not mine but mine does look like these

mcfisticuffs

Wear.

Skyhawk172

so they are suppose to look like this uhm!

nwGTS

Any reasoning would only be speculation on my part but I've noticed those ridges align with the drilled venting holes.

Dan GSR

what pads are you using?

motopix

I'm confused. Are you talking about the ridges on the face of the rotor top and bottom, as in wear on the rotor where the pads contact it?

Bruce In Philly

That is normal wear... the lip, the groove/furrows... all normal. I replaced the rotors on my 2009 around 75K miles and that is how they looked.... worse I think. That is no reason to worry. How many miles on the car?

The grey "hat" inner hub thing, has a number stamped on it. That is the minimum thickness of the rotor' operating spec in millimeters. Measure the thickness using a caliper... if you are at or less than that, then the rotors require replacement. Even if you are there, there is no reason to panic.... the rotors and brakes in general are way overbuilt for normal street use.

There are folks here on this forum who can tell you what tat minimum thickness should be. Again, there is no reason to worry or panic.

Peace
Bruce in Philly

Macster

Smooth is relative. Some mild grooving is normal especially if the brakes are used hard and often, like on the track. Changing pads without changing rotors can exacerbate the grooving too.

The brake rotor in the pic appears to be near its replacement time given the nearly 1mm ridge around the outside of the rotor. That's 2mm of wear and that's the wear limit of these rotors.

Skyhawk172

Thanks for the all the replies
the car has 67000 miles
from car fax the rears where replaced at 27,000
and the fronts where replaced at 47,000

eagle1960

If you look at the holes drilled in the rotor, every so often outside the circle of the outermost holes there should be a concave dimple which does not go through. My understanding is that these are wear indicators. I think I see some of yours In the picture. If so you still have life left. There is no way to know for sure how many miles it takes to wear them out. All depends on how the car is driven.

Bruce In Philly

You have to remove the engine to replace the spark plugs on a turbo? Really? Hmmmmm...... this all looks fishy to me. Rears at 27K miles!! Really??? Usually the fronts are first to go but rarely would rotors need to be replaced at such a low mileage.... unless there is heavy track work going on. It appears this car was over maintained... in other words, it either had a hard life or was taken advantage of.

Peace
Bruce in Philly

Skyhawk172

I will take "well cared for" for a $1000.00 Alex

3Series

Measuring is the proper way. The easy way is to look at the wear dimple. Porsche rotors have a wear indicator. Sebro also has them.

Iceter

Look at the dealership that did the work. I'm putting my money on the service department sticking it to the PO.

And that's assuming that they actually did the work they charged him for.

Skyhawk172

you guys are barrel of laughs, who is the PO?