Price: $150.00         

Item #KA-019E: Kaisei 019 main tubeset, 4130 .8/.5/.8 quad butted standard tubing. This includes head tube, seat tube, down tube, top tube and steerer tube. You must choose chain stays, seat stays and fork blades as separate items, but they are included in the tubeset price.

Description---O.D.------Wall------Butt/taper/center/taper/butt------length
Top Tube 25.4mm .8-.5-.8 150---50-----280---50----80 610mm
Down Tube 28.6mm .8-.5-.8 130---50-----290---50---120 640mm
Seat Tube 28.6mm .8-.5-.7 130---50----290---50----120 640mm
Head Tube 31.8 1mm N/A 210mm
Recommended seat post size 27.0mm

Note; this looks like double butted on paper but what you can't tell from the numbers is that there is a constant taper from the "obvious" butt to the thinnest center section and then a constant taper back out to the butt at the other end of the top & downtubes. This constitutes the quad butted feature. The seat tube is a true double butted tube.