Originally Posted by
Trakhak
The advantage of the 2 x 4 method is that, if you begin with a frame whose alignment has been measured to be correct, you can bend one side at a time the correct distance. In the case of a 124-mm OLD being changed to 130 mm, that would be 3 mm per side, obviously.
My 2x4 method is not your 2x4 method - I just put the two pieces inside the chainstays next to the dropouts and lever them against each other - if the ends are 6 inches above the stays and the pieces are 2 ft long I have 4x mechanical advantage. If the stays don't bend the same on each side I clamp the bottom bracket shell in the bench vise and push/pull them into alignment, but the 2x4 works well enough most of the time.