Monday, December 16, 2013

Now available: Curved tubes for framebuilders

I've spent quite a while figuring out a reasonable technique for making nice curved tubes with butted tubing and I've had a reasonable amount of luck (after ruining plenty of fine American steel in the process of learning what not to do). If these items are popular I may offer some other options that I commonly use (curved 31.8mm seat tube for 27.2 post, curved 34.9 seat tube for 31.6 dropper post, curved 31.8 supertherm top/down tube, 19mm twin toptube/seatstays?)

Without further ado:

Please note: All bent tubes will exhibit some minor ovalization. It is up to the end user/builder to determine appropriate diameter/butting and miter/cope/join appropriately. There is no visible ripple/flaw at butts/butt transitions (transition from bent/straight on seat tubes is visible). Butts marked for builder's convenience on request.

28.6mm diameter 9/6 single butted seat tube. 650mm total length, 75mm butt. Bottom 250mm is curved 10mm (approximately 1750mm radius). Appropriate for short-chainstay frame designs and will take a 27.2 seatpost. REQUIRES a sleeve or lug at toptube/seatstay cluster. 4130 cromoly. Bent/straight transition is visually obvious and overenthusiastic insertion of a too-long seatpost can damage this tube. Builder must adjust seat angle for desired saddle positioning. $60

-28.6mm diameter 9/6/9 double butted x 600mm. Butts are 100mm at each end. Curved 25mm over total 600mm length (approximately 1750mm radius). Appropriate for toptubes with curve oriented either up or down. 4130 cromoly.  Butt transitions are NOT visible after bending. $70

-31.8mm diameter 9/6/9 double butted x 600mm. 90mm butts at each end. Curved 25mm over total 600mm length  (approximately 1750mm radius). Appropriate for toptubes oriented either up or down, or for light-duty downtube. 4130 cromoly. Butt transitions are NOT visible after bending. $70

-Custom tube bending. Want something unusual? I can bend most sizes of commonly used bike frame tubing, both straightgauge and butted. Heat treated material will cost considerably more, but yes, I can do it. Contact me for a quote.

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