Rotor thickness inside/outside

Brakes have an occasional light rumble and I see inside disc is .350 and the other is .400. Pad thickness is ok. At least .250. There is a slight ridge on inside/outside. Is .050 disc difference cause for concern?


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No. Cheap rotors can be that far off when new.

Just be sure to check for a sticking caliper or slide pins.

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looks okay to me

By web do you mean disc?

Those interconnecting structures between the rotor plates. They look fine to me. I’m used to seeing lots of flaking there. The rotor face looks like it needs attention however…

The ridges look large to me. After you machine the rotors, the ridges will be even more pronounced. I’d replace the rotors.

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Ok. I wouldn’t give their thickness a second thought.

Find out what the discard thickness and or minimum machine to thickness is, and measure the thickness of the rotor disc, if above 0.030" from the discard thickness, then machine them, should only take about 0.010" (maybe less) from your description and the looks of them, they look like most normal rotors I see in my part of the world… Or if enough above the minimum machine to thickness -same thing, turn them…
Or just replace them, your choice… lol

That is of course if you can get them off without having to use a 5 lb hammer…

Cooling vanes..

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OK, now the question makes sense. I’d hold off doing anything until either the pads wear out or the rumble becomes significant. I’d replace pads and rotor in either case.

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The ridges are removed when machining rotors.

Tester

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Inner and outer planes have different thicknesses, sometimes it is by design, other times it is just a sloppy casting. In your case the difference is not a concern.


Look closely at the rotor below, the chamfered edge is a rough visual guide to discard thickness, if there is no chamfer remaining, the rotor is no longer useable. Follow up with a micrometer measurement. Your rotors appear to have a reasonable amount of material remaining, do you have a rotor micrometer?