Originally Posted by
well biked
I'll guarantee you that when you flex the stays apart by hand, each side is not moving the same amount off of center. In fact, you're probably moving one side 4mm and the other side none. So with the wheel in the frame, you've just misaligned the rear triangle by 4mm. Or maybe 3mm. Or maybe 2.5mm. Who knows.
That's conjecture. You guarantee something in the beginning of the paragraph, but by the end you don't know.
Originally Posted by
well biked
If it's worth doing, it's worth doing right. And I'll add that if someone is changing the frame spacing to run a modern 10 speed cassette with indexed shifting, for example, the derailleur hanger alignment is critical.
Likely. I wouldn't know or care as I use friction shifting exclusively.
I'm not advocating that the OP not have his frame spread. It's his bike to do with what he feels best. The new Shimano 105 hub that I just put in my '87 Voyageur with 126mm spaced dropouts went in easier than the front wheel. It has been my experience that cold setting the frame for 4mm difference isn't necessary. That is all.