For those who actually care about this, there's a simple way, which requires minimal skill or effort.
Put the bike along a wall. Brace the bar solidly against the wall with the bottom and outside top stabilizing it. Measure wall to a lever reference point. Flip bike and repeat.
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An ounce of diagnosis is worth a pound of cure.
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“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
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