i got a Ritchey WCS Logic Zero PF Headset on my addict R1. when i got the headset, there were no crown race included. the seller said all was in the packaging when there was none.

so i brought to LBS and they didn't have the one from ritchey. but instead, they had a chris king crown race that they said fits perfectly and is universal.

now i got some play in the headset, so are crown race universal and interchangeable?

No, they vary. Chris King makes his own *everything* so his parts are not a good place to start mixing and matching, either. You may be able to find a suitable crown race from another maker, though.

No crown races aren't universal, but they type you use may be.

I know this sounds contradictory, but there are two basic types of crown races. The traditional race on which the balls actually run has to be a correct match for cup in the head tube, and the balls used. So for traditional headsets crown races are definitely not universal.

OTOH, cartridge bearings don't have a true crown race of the fork, it's part of the bearing. What's on the fork is only a centering cone to locate the inner baring race, and therefore no exact match is required, and many are in fact the same. However there may be a snag depending on your headset. Some lower cups overlap the outside of the crown race (we'll continue to call it that anyway) to make a tight weather seal. So there may be an issue of a correct match. This is easy enough to check, by simply fitting th race to the lower bearing and seeing if it looks close enough to work right..

the ck crown race to the lower bearing looks pretty close and snug. they have about 1 - 1.5mm gap when my fork is installed on. but i notice the top cap portion has a bit of tilt within the gaps.. so that's what worried me in the first place.. then later i felt like the bike frame will flex when i gently press down from the top tube and then lift up, all the while leaving the front wheel on the ground. the play is very subtle.. and this being my first CF bike.. i'm a bit paranoid about cracking

Maybe you need another spacer. Try removing the top cap and bolt and putting a 5mm spacer on top of the stem, then add the top cap and bolt again. Loosen the stem and lightly tighten the top bolt until you have enough preload that the headset spacers don't turn by hand anymore. Now tighten your stem again.

Any good?

Not all headset bearings use the same contact angle for the crown race and bearing. 36° and 45° are the two common angles. I don't know if Chris King uses either of those, or something of his own choosing. But if you have a mismatch, it may not ever work quite the way it's supposed to. In that case, I'd measure the bearing's contact angle and pick a crown race that fits it.