Originally Posted by ShannonM

I'm going to retry the AR this Sunday afternoon. I just realized that I boneheaded the bottom bracket math. I was looking at my very inaccurate measurement of the chainring / chainstay gap, and thinking, "3-4 mm gap. 122.5 - 118 = 4.5. Nope... need a new derailleur."

In my haste, I overlooked two significant facts. First, given that I used an inch / foot tape measure and my eye to take the measurement, the odds are that that measurement is not only wrong, but wrong in the direction of "too small." Second, and more importantly, the difference in gap isn't 4.5 mm, but 2.25, because symmetry.

There's 2 or 3 118mm UN-whatevers in the box-o'-bottom-brackets at the Bike Kitchen, so I'm gonna try that and the AR FD and see if it'll work. I have hopes, since it was oh-so-close before.

One question: Is ring / stay clearance as simple as "if it doesn't rub, it works?"

--Shannon