Originally Posted by
gugie
Of course you're right, I didn't take the time to look at the picture I posted!
On the other hand...
From Kaisei:
Kaisei 019E CR-MO Quadruple Butted Tubing
Chromium Molybdenum (CRMO)
Top Tube: Outer Diam- 25.4mm / Length- 580mm / Wall Thickness- 0.8mm> 0.5mm> 0.4mm> 0.7mm
Down Tube: Outer Diam- 28.6mm / Length- 630mm / Wall Thickness- 0.8mm> 0.5mm> 0.4mm> 0.8mm
Seat Tube: Outer Diam- 28.6mm / Length- 610mm / Wall Thickness- 0.8mm> 0.5mm> 0.4mm> 0.7mm
Head Tube: Outer Diam- 31.8mm / Length- 180mm / Wall Thickness- 1.0mm-
Chain Stays: Outer Diam 1-22.2 mm / Outer Diam 2- 12mm / Length- 410mm / Wall Thickness- 0.8mm-
Seat Stays: Outer Diam 1- mm / Outer Diam 2- mm / Length- mm / Wall Thickness- mm-
Fork Blades: Outer Diam 1- 28/20mm / Outer Diam 2- 12mm / Length- 400mm / Wall Thickness- 0.95mm-
Fork Steerer: Outer Diam- 25.4mm / Length- 200mm / Wall Thickness- 2.2mm> 1.6mm
The three main tubes on this set are clearly stepped down more than once.
Kaisei was the name of the company that rose out of the nankruptcy of Ishiwata. It was owned by a former Ishiwata director and operated out of the former Ishiwata factory, using the Ishiwata tooling. They also acquired all the tubeset names used by Ishiwata. Essentially, they are Ishiwata tubesets by another name.
However, the fourth butt is not a butt in the traditonal sense. Basically, it's a triple butted tube with a mid-section that has long gradual taper(s) to the thinnest section of the tube. So, in that sense there is no additional step down, it's more of a ramp. See attached illustration from a Kaisei catalog. Note that this is the same illustration previously used by Ishiwata. In these illustrations, T1 is the thickest section, followed by T4, then T2 and T3, in order of decreasing thickness.
