Old 08-31-12, 12:50 PM
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Originally Posted by DScience View Post
I'm not trying to "band aid" things, but I don't KNOW for certain that the wheel NEEDS to be dished! Second, I don't have rear drop outs. It's a track bike, with rear fork ends and I've checked that those are aligned and to the best of my knowledge they are.
When you flipped the wheel around and found that the offset was flipped as well that was total proof that the wheel isn't dished correctly. If it was anything else the amount of offset to the other side would not have been the same amount as the first way.

Now if you flipped the wheel around and found that it was absolutely centered where it was offset as shown in your pictures then you'd have TWO things at play. One would be that the wheel wasn't perfectly dished and the other that the dropout stops were not quite absolutely square on. If you then zeroed out the dish in the wheel you'd find that there would still be a small amount of offset but that it would stay the same when the wheel was flipped. The remaining FIXED SIDE offset would be due to the dropout stops not being set identically.

This, of course, assumes that your dropouts have the stop screws which you can set. Not all bikes have those. Now if you're using axle tugs and the offset switches when you flip the wheel then you really don't know if the issue is with the wheel dish or if the axle tugs are not set spot on since you flipped BOTH the wheel AND the axle tugs. When you switch two things you can't tell which of the two is the issue.

And keep in mind that when you flip the wheel around to test this you're seeing DOUBLE the difference. The amount you need to pull the dish is only going to be half of the total difference from the flip.

For more than a few shops 2mm is likely felt to be good enough. Or possibly they didn't do a last minute dish check. Either fine tune it yourself or take it back and ask for it to be zeroed out for dish.

The key is in correctly interpreting what you see when you do such tests and what the test is designed to indicate.
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