Thanks Michael, again for mentioning my frames on the List - this time in reference to the twin-seat tube type of short wheelbase design.
There have been quite a few manufacturers and framebuilders who have
adopted this type of structure to give a shorter rear triangle and I
suppose that if you have no access to tube bending machinery for making
curved tubes, then this design is an easy alternative, although less
sensible than a curved tube.
>From memory I think the French probably hold the record for the number
of variations on a the theme, with even Motobecane producing
a frame for some of its Pro team in the early 80s, with Alain Bondue,
the former World Champion Pro pursuit champion having ridden one. It
wasn't a particularly well conceived or elegant design. Mecacycle of St
Etienne become very well known for its "Turbo" model, that was available
in road, track and touring versions. This also saw the light of day
under Cycles Delcroix transfers, Cizeron, and Bernard Thevenet brands.
Chaplait a "constructeur" from the 30s and 40s ( I think) also used the
structure on tandem frames. My good friend Jean-Marie Duret also
produced a lot of these frames, under his "Geliano" brand in the
early-to-mid 80s, using "Camus" brand aero section seat-stays
manufactured by AMR. for the twin-tubes. These frames were shown at the
Paris Show in about 1983, sprayed in wild colours, and I reckon that
Jean-Marie can take the credit for starting the rage for "flamme"
finishes that sparked off a year or so later.
In the UK the best known brand was the SAXON which was in common use in the late 30s. I gather (Mick can you confirm?) that Claud Butler continued the design for a short while after he bought out the rights to the "Saxon" name. Around this time, or not too long after, Ellis-Briggs produced a twin-tube design using tubes curved along their full length, whereas Chas Roberts simply curved the bottom tubes on the bike that Dale owns. Both of these designs seem to have "lost the plot" Why use both curved tubes and twin-tubes, when either design will achieve the same saving on chain-stay length? Hopper also used a variation of the design, but for a different reason on its model where the chainset sits in between the tubes(Nigel...help me out here!)
In the early to mid 80s Condor made a prototype for one of their "sponsored" amateur riders, Martin Roach, who was a big name in time trialling at the time. Their design dispensed with any length of actual seat-tube and managed to link up at the seat-tube "collar" with twin top-tubes. It seemed unnecessarily complicated, but was very skillfully built.
Ellis-Briggs only built six of the curved twin-tube frames, and the present members of the family who still run the business at Shipley have no recollection of or photos of them. The company eventually produced, but in penny numbers, a straight tube version of the frame. I know of only one in existence, and of three of the others.
In addition to Rigi, and possibly now Torpado, in Italy, the small high class company of Freschi of Milan, produced a design very similar to the Ebay frame, in the 80s
My own contribution to this genre of frame has not been considerable, probably totalling no more than a dozen, most of them being "retro" club designs, permitting the fitting of mudguards which passed between the twin-tubes. I do however recall building a splendid time-trialling frame for which the customer specified "drillium" lugs.
The CR title for this item refers to split seat tube frames, but none of the frames mentioned above actually had "split" tubes. I think the distinction for originating this type of frame must be give to a fomer copper-smith turned framebuilder, called "Bebere" who built all the phenomenal "one-offs" for Geliano in the 80s and early 90s. He literally took round tubes and split them along the length for some way, splayed them out and plated them into "D" sections. To my eternal shame I copied this design, but with Geliano's permission, and used the method on both straight and curved seat tubes, and on down tubes. They were a devil of a lot of work, but produced an astonishingly rigid "bottom-end" to frames. I think all of the frames I made with this split structure were time-trialling models. I have photos of all these frames but although I have recently invested in all manner of scanning and digital photographic equipment I cannot claim to be making very much headway. Only time will tell!
Norris Lockley, Settle UK (where it is far colder then Sancerre, France, but where there are no 13-year-old kids burning cars in the streets!)