Originally Posted by
unterhausen
are those measurements after you remove the 6cm of spacers?
Those rings only work if they are brazed on, so that means new paint.
The upper ring is less important than the lower ring. So depending on how thick the head tube tubing is, the top ring might not be strictly necessary.
As well as how tight the upper headset cup is pressed into the head tube end. I forget where or with which brand but I do recall frames being reamed to have a non interference fit with the cups. The cups were to be lock tighted in place.
With a view to how the upper cup fits I would have little concerns about cutting down the head tube on this bike. However do think about the reversible options first. Cutting off some part of a frame is often regretted later. Andy