Originally Posted by Al.canoe
The lbs owner who respaced my frame was a retired frame builder who thought it was necessary though it was a steel frame. He had the tools and he didn't charge me anything.
It may be necessary in some cases, but not if you'll be flexing the frame only 2mm on each side. Cold-worked respacing may make the frame more easy to get the rear wheel in and out, but this ain't much of an issue unless you flat a lot. And even if, it's not tough to get a 130-spaced rear wheel in and out of a 126-spaced steel frame. I've done it with a few, as have lots of other people around here.