The chainstays on a frame I have are dimpled, presumably for chain clearance. Both chainstays have identical dimples on the inside, and the drive-side chainstay has a dimple on the outside as well, which the other chainstay does not have.
Will this make it difficult to respace the frame to accept a larger hub? I am thinking of using the Sheldon Brown method of respacing with a 2x4. Will the dimples cause the chainstays to bend unevenly, or bend in the wrong place?