Originally Posted by
abdon
I'm into old frames and this was one tool I wanted to add to my bag and just never got around. Well I did, and the first frame I attached to shows the hanger to be about 1/4" off at the rim.
How much misalignment is too much? If math serves me right on a 700c tire that's a 0.5868 of a degree off.
It's simply the mm gap, no need to think about degrees. If you look at online stuff, there's a few mm leeway, Park says 3mm. I know from personal experience that the more speeds in back, the closer it has to be. With my 9 and 10 speed stuff, I eyeballed it and never had a hanger-related issue. With the AXS 12 speed stuff I have, it has to be within a couple of mm. I use an inexpensive tool I got on Ebay and it works perfectly to get within a few mm, and therefore perfect shifting.