Is a rotor warped?

[BMFR6]

Well I want to mount a set of stock rotors on my rain tires/rims. I have a couple sets of stock rotors and want to see if any of them are warped before I move forward. Is there an easy way to tell if a rotor is slightly warped prior to mounting it? I'm sure I can mount them, put the rim on the bike and spin it using a fixed object to gauge if it wobbles but; if there is an easier way I am all ears.

[duff daddy]

yea find a flat bench and then take a gander at it laying flat... or you can take a micromiter and measure it at different places, most of the time if a rotor is warped its twisted thus being a thickness vairation and the micrometer will tell you... but the easiest is just lay them on the glass of your car (side window) and that iwll tell you real quick

[Paul_E_D]

The rotor very rarely warps. It's the carrier that usually get bent out of spec because it's aluminum. Mount it on the wheel and spin it using a fixed object next to it. If you find a spot that's clearly out of whack, you can try to fix it by carefully tweaking the carrier in the desired direction and checking runout again.

None of mine are particularly perfect. Sand the rotor with some fine grit paper and install it.