Re:
Raleigh standard tubing was seam welded, seat tube outside 1 1/8 inches, inside 1 inch (25.4mm)
Butted 531 usually means seat tube 20 /23G, and inside at the top 27.2mm. Plain gauge 531 probably 26,4mm inside.
It is poosible to look down the inside of the seat tube and see the electric seam weld.
Keith
Raleigh standard tubing was seam welded, seat tube outside 1 1/8 inches, inside 1 inch (25.4mm)
Butted 531 usually means seat tube 20 /23G, and inside at the top 27.2mm. Plain gauge 531 probably 26,4mm inside.
It is poosible to look down the inside of the seat tube and see the electric seam weld.
Keith