How The Tail Got Twisted
Jack Denny once described the purpose of the curly stays in a magazine interview. The idea was born in the 1930s when road races took place over bad roads, often over cobblestones. The raked fork in front absorbed some of the road shocks, but conventional straight rear triangles transmitted all the road shocks to the frame causing the whole bike to rattle and shake. This rattling and shaking is wasted motion and translates into lower speeds and lost time. Denny believed that a sort of a fork in back would absorb some more of the shock, resulting in less rattling and shaking and, in theory at least, less lost motion. The idea was not to provide a bouncy suspension, as on modern mountain bikes, but rather to let the dropouts vibrate--hence, the official designation, vibrant stays. The claim of the curly stays is untested, but it has been proven that suspended mountain bikes are faster over some kinds of terrain than conventional bikes, so there may be merit to Denny's idea. The curly stays do not offer any functional advantage to the cycling tourist, Denny said in the interview; nor, presumably, to the track cyclist. Nonetheless, many track frames were fitted with the elegant stays, and this brings us to another twist in the tale.
1936 World and Olympic Champion, Toni Merkens, riding his 'no-name' Hetchins.
Hetchins frames featured some other unorthodox designs as well. For example, the hellenic and fastback stays which result in an equilateral triangle.
Hellenic stays cross the seat tube and anchor under the top tube. The name comes from Fred Hellens, who developed the design in 1923.
Hellenics often featured a pulley to guide the brake cable under the top tube, to be used with center pull brakes.
The first one was a VM design, sold in July 1967 (production started in 1966), others were produced with other lug sets (incl. Mag. Opus and Italia); the last was produced in 1979 or '80 (plus two recent ones built in 1987 and 1995). The design was not popular and only about 75 were made. They are rare and highly sought by collectors.
Below is a reprint of an article from 1967.
The fastback design anchors on the seat tube below the seat lug.
The shot-in design anchors the stays higher up than the fastback, part of the seat lug but neither wrapping over the seat lug nor attached to the binder bolt.
The italianate design, pictured at the right, integrates the stays with the seat binder, giving a very neat appearance. This feature, and scalloped seat lugs, were popular in the 1970s and available on most any frame, not only on the Italia model.
Last but not least dept.
Above: ladies triple curly;
Above: Experto Crede with a double curl. The reason for the extra curl is not certain, but the long wheelbase suggests that it may have been a one-off suited to this particular geometry.
PS There were also conventional Hetchins stays.