Originally Posted by dabac

Well, it's not doing you any good, but I don't think that's the biggest villain in this case.
I've ridden bikes that have been off by about the double without any dramatical handlig consequences.
One I spotted during cold setting. Another remained undetected until a wheel swap revealed that the original wheel had a custom dish to compensate for the rear triangles being off.
But then I don't do much hands-off riding at the best of times.


I'm not certain I understand the geometry here. Fork blades generally point away from each other a bit. They're closer together at the crown than by the dropouts. That itself doesn't tell you anything.
Let's say you put the fork on a table, with the crown resting at the the table and the blades hanging over the edge; both fork blades need to be at the same distance from a line drawn through the steerer tube, both when looking at the fork from above and from the side.
And while doing that, the distance between the dropouts should be a good match to the width or O.L.D. measurement of the hub.
So blades can be off both sideways and front or rear. It can affect either one blade, or both. It's a bit tricker to measure than a frame.
And it can certainly do funny things to the handling of the bike.