OK, I did a dumb thing: I ordered my brakes from Hayes and went to install them last night. Dumb me! Every other RST fork I've had uses 51mm IS mount. They changed the lowers this year (as are a lot of other mfrs) to the Hayes post-mount. Only I never looked that closely at the lowers when I was figuring which adapters to order with the brakes -- thinking I knew what they were (huh!)
So now I'm scrambling for a 74mm post-to-8" rotor adapter. Local shops are out; but one (not mine ) squeezed me in an Avid on a next-day order they were placing (whew!)
Now my question is (after you get done laughing at me): Does the Avid adapter have the exact same hole offset and post standoff as the Hayes adapter? If not, I may still have to order a Hayes from an online and have it overnighted (race this weekend ) Please tell me some good news!