I know Miyata draws its own tubes, and (I believe) supplies tubes to other companies. As I recall, Miyata's "spline triple-butted" tubes used three different butts ("shut up, Beavis!") with reinforing ridges ("splines") in high-stress areas. I don't know if it's seamless or seamed, though something in my memory seems to tell me it's seamless.
I have a Team Miyata (don't know the date, but definitely on-topic) with nice cast bits, like Miyata's symbol on the brake bridge and an M encased in a rectangle on the lower head lug (also stuff like number plate bosses -- it even came with the hardware). Very light and very solid; I don't have the courage (or the local descents) to push it, but the bike's high-speed stability and comfort level seem to far exceed mine. ;-)
Dennis Ryan Louisville, KY
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org]On Behalf Of nath Sent: Thursday, April 24, 2003 8:34 AM To: Joe Bender-Zanoni Cc: classicrendezvous@bikelist.org Subject: Re: [CR]Was Japanese bike makers, Now Butted Tubing
>>> If I remember the quad and triple butted tubing was seamed
>>> and could not be made by the seamless method with mandrels.
Joe, I think the Ishiwata triple-butted tubing was available in both the seamed and seamless varieties.
For an out-of-timeline example, the 1992 Bridgestone RB-2 was made with seamed Ishiwata triple-butted, while the more expensive RB-1 was made with seamless Ishiwata triple-butted. At least that's the way I'm remembering the Bridgestone catalog's presentation. (Grant? You there?)
But I don't know about other tubing brands, or earlier examples. I suspect, though, that Fuji's quad-butted Valite was NOT seamless. . . .
nath dresser
spring green, wi