Kaisei Tubeset, Oversize


Ultimate performance for tall, heavy and/or very strong riders. Oversize tubes with ultra-thin 0.7-0.4-0.7 mm walls give the frame stiffness without detracting from its lively feel. (Down tube has 0.7-0.5-0.7 mm walls for greater resistance to dents.) The main tubes are heat treated for ultimate strength and durability.

Each set includes:

  • Oversize top tube: ø 28.6 mm, long or short thinwall “belly”
  • Oversize down tube: ø 31.8 mm, long or short thinwall “belly”
  • Seat tube: 28.6 mm diameter, for 27.2 mm seatpost, standard or long thinwall “belly”
  • Head tube: standard or OS
  • Seatstays: single taper
  • Chainstays: 22.2 mm round, 0.7, 0.8, or 1.0 mm wall thickness, straight or curved (+$20)


Read more about ride characteristics of our three tubesets in these blog posts:

  • Superlight with ultra-thinwall tubes for the lightest, most flexible frame
  • ‘Mule’ with a stiffer downtube and superlight top tube
  • Oversize for stiffer frames


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.

  • Check individual tubes for specs.
  • Main tubes are heat-treated for ultimate strength and durability.