Kaisei Down Tubes


Superlight tubes with Kaisei’s famous quality, in lengths and with butting profiles for all frame sizes. Heat-treated CrMo for ultimate strength and durability.

Made in Japan.


The performance of steel bikes has been perfected to such a degree that even today, steel is the material of choice for the bikes that take us on our adventures. Kaisei makes the best steel tubing in the world, widely respected for its consistent quality and perfect roundness. Long reserved for the track bikes of Japan’s Keirin professionals (who race on steel bikes), Rene Herse now offers Kaisei tubing in custom-drawn dimensions for modern allroad and randonneur bikes.

Click here to read more about Kaisei tubing and why even today, the best bikes are made from steel tubing.

  • Heat-treated CrMo
  • "Short" sizes have shorter thin "bellies" and longer butted ends, for small frames
  • "Long" sizes have longer thin "bellies" and shorter butted ends, for large superlight frames
  • Overall lengths: Std. short: 610 mm; Std. long: 650 mm; OS short: 630 mm; OS long: 670 mm
  • Butting dimensions: see drawings