Interesting post - I've never heard of brazing inside a head tube before as you mention with the Rene Herse. Would love to see pics of that and learn a little about how it's done.
As for using over-sized tubing to qwell front end shimmy I can certainly see where shimmy problems can easily arise from loaded touring/camping bikes not having adequate construction methods or properly chosen tubing. But I'm not so sure that every bike that has "normal" diameter tubing suffers from this nor that over-sized tubing is always the solution (not saying that's what you put forth by the way). I would think a bigger culprit of shimmy would be poor geometry or even a badly adjusted headset or out of true wheel.
I'm sure the builders on this list will have more definitive answers and some very interesting things to say.
John Price
Denver, CO
-----Original Message----- From: ΓΈ [mailto:Sterling@tns.net] Sent: Tuesday, July 09, 2002 2:03 PM To: Classicrendezvous@bikelist.org Subject: [CR]"Mojo" or B. S. Confente/Baylis/Herse
A couple of ideas regarding frame building/construction came together for me in the past few weeks. I had the pleasure of going over the construction of some of the finest framesets ever made ( Masi , Colnago , Herse , Cinelli and Baylis) with Brian Baylis. I discovered a lot of things I should have been looking for all the years that I have been around bicycles. I'm a former racer , mechanic , and now a collector. It's amazing how much that I had been missing all these years . However the real eye opener came when we got to the elements that you can not see until you investigate the construction of the junctions inside the Bottom Bracket shell and head tubes. It is now clear to me that all frame sets are constructed a little differently or with different levels of care for the quality of the finished product. With this new knowledge I am better able to determine if a bikes reputation is based ( "Mojo" , Million Dollar Marketing Campaigns, B. S. , or Real Engineering/Constructor/ Genius )!
There is an interesting article in this months Velo News , which discusses the elements of front end shimmy. Shimmy , head shake , high-speed wobble is caused by top tube rigidity or lack of it. The reason I bring this up is because when we examined the A model Rene Herse frameset it became clear that Herse understood this point well. His frameset was constructed so that the top tube and down tube , in addition to the brazing at the lugs , were also brazed inside the head tube. The French so clearly understood the elements of front end shimmy , that their tube sets also included an oversized top tube. It is also known that Rene Herse built racing bikes with oversized down tubes for extra rigidity , and I believe I saw a Rene Herse Randonneur bike on Ebay last year that also had the oversize down tube treatment . I'm sure there would have been more of oversized tube sets , if builders/constructors did not have to make the lugs themselves to fit the oversized tubes. Bates settled on tubes that were oversized in the center sections only , because he could not get lugs to go with a complete oversize tube set.
I would like to hear from the frame builders/constructors on the list as to what they think of these ideas ( tubes brazed to the head tube; oversized tube sets). This best reason for not brazing the tubes inside the head tube is all the extra work , only Rene Herse and Alex Singer were willing to go the extra mile. Regarding oversized tubes I have a 1995 De Rosa Giro De Italia it has oversized tubes and is one of the best riding bikes in my collection. Would having builders like Baylis and Sachs build bikes with oversized tubes ruin the attempt to capture the past with this type of build? Any comments from others?
Thank you!
Sterling Peters
San Diego