Hello, can someone elaborate about this regulation:
1.3.3.2.5. The maximum outside diameter may not exceed 65 ± 0.5mm
What was the reasoning behind the Ø limitation. My feeling is that the roots of it was that over Ø65 old tube heads had therefor a too big scoop/open side.
I cannot relate or think of any “exploit” implying a “too big” outside diameter.