Hi,

I'm working on a dropout. I am working with manufacturer specs to set the size of different parts of the dropout but I'm not sure what size the hole of the fame hanger bolt should be.

The docs don't specify its size. It looks like 10mm from the drawing, but not 100% sure. what is it ?

10mm, 100tpi fine pitch is typical

Remember www.sheldonbrown.com has a lot of reference numbers for sizes etc. Also, www.parktools.com has a lot of good info.

Gray