ClarkinHawaii

Checking a batch of new rims for "flatness" by holding each rim up against a large sheet of glass and seeing if there is any "wiggle". No wiggle in any of the rims, except one--it has just a tiny wiggle--meaning it is maybe less than 1mm away from being flat. Sooooo . . . how much wiggle makes a rim defective? How much wiggle is easily compensated for by spoke tensions that are within acceptable range? Thank you.

skoda2

Greetings, I've been wrenching bikes for forty plus years, and don't recall ever checking any new rim, before building.
Cheers

cny-bikeman

To accurately answer your question one would have needed to measure deflection of rims prior to building, build even if the deflection seemed borderline, determine whether the variation in spoke tension was acceptable, and record the results, which might vary with different rim styles. In other words nobody can give you more than an unsupported opinion. Further, it does not matter what one of us thinks ("The guys on the Internet said it's defective") - you need to get the provider to agree to replace a given rim. If you are a regular customer I doubt a stink will be raised about a single rim.

Bill Kapaun

Flip it over and see if you have a corresponding low spot on the opposite side.
If you don't, I'd be more concerned.
I usually run a caliper around the rims making sure there aren't any noticeable "wows". (as if a wheel was ran into a curb and spread the lips)

FBinNY 

Certainly more than that.

How much depends on rim rigidity, spoke count and the exact nature of any bend (how local, vs. spread out). Like the person above, I don't remember ever checking or rejecting a new rim for roundness or flatness.