randyjawa 

I assume we are talking about a rim that is actually bent, not just out of true due to improper spoke adjustment.

I hold the bent rim up against a rim, I know to be straight. If, at any point, the gap between the two rims exceeds 1/8"(3.2mm) I toss the rim, assuming we are talking about alloy rims. Steel rims I might allow a bit more but generally apply the same standard applies to them also.

Keep in mind, when trying to measure gap, rotate the rims and measure at different points.

In addition to wobble, you need to look at hop also, and flat spots. These can create problems.

Perhaps this is being over cautious but I have never had good luck with a rim that exceeds that much bend. My guess is pulling the rim back into true places considerable more tension on the spokes doing the work, which makes for a weak and undependable wheel, in my opinion.