In addition to individual Kaisei frame tubes, Compass Cycles offers three complete tubesets: Superlight, ‘Mule’ and Oversize. Each tubeset is based on bikes that we have found to work extremely well. The Superlight set is the lightest steel tubeset available today, great for riders who prefer a flexible frame. The ‘Mule’ set uses an oversized down tube for a little firmer feel. It’s also better for carrying a front camping load.
The Oversize tubeset is made from thinwall oversized tubing to offer the ultimate performance for those who prefer a somewhat stiffer frame. BQ contributor and constructeur Hahn Rossman’s heavier build is accompanied by a higher power output, and he builds his own bikes with oversized tubing, both his randonneur bikes (above) and the cyclocross bikes he races with panache and passion.
The oversize top tube with ultra-thin 0.7-0.4-0.7 mm walls adds stiffness to the frame without detracting from its lively feel. Kaisei keeps the ‘belly’ of the down tube to a slightly more conservative 0.5 mm, instead of the ultra-thin 0.4 mm, because the large-diameter tubes dent too easily when they are too thin. (Down tubes are larger than top tubes, making them less convex and easier to dent.) Since our tubes are available with longer ‘bellies,’ they are still lighter than other tubes with thinner-wall, but shorter, bellies.
How does a bike made with the Oversize tubeset ride? I’ve ridden Hahn’s bikes – we share the same bike fit – and they feel subtly different from mine. They still ‘plane’ – by most standards, this tubeset is very light and still has flex in the right places – but they do have a more planted feel. For me, they work best with a higher power output and a slightly lower cadence.
Interestingly, descending feels the same on all our bikes, regardless of the tubes used in the frame. We’ve found that frame stiffness makes little difference in how a bike handles – which makes sense when you consider that there are no significant side loads on a frame when you aren’t pedaling.
The Oversize tubeset is a great choice if you want or need a little more stiffness in your frame than our other Kaisei tubesets offer. That makes it perfect for tall, heavy and/or strong riders. This is also the tubeset I’d chose for a camping bike that carries rear panniers in addition to a front load. Above you see both my ‘Mule’ and Hahn’s Oversize bike on top of Shirabiso Pass in Japan during the Nihon Alps 600 km Super Randonnée – each bike perfect for its rider during this challenging ride.
The final tubing selection for your bike is something to discuss with your frame builder, who will design your frame based your build, riding style, preference, and intended use of the bike. All our Kaisei tubesets offer excellent performance that comes with a carefully designed balance of frame stiffness. As a Compass exclusive, we offer the Kaisei tubesets in two lengths, so you can get tubes optimized for your frame size. All tubes we sell feature Kaisei’s unmatched quality and experience that comes from supplying the tubes for the frames of thousands of professional Keirin racers. We import these tubes because we feel that there are no better tubes anywhere.