Re: [Classicrendezvous] Hellenic stays ( Equilateral rear triangle)

(Example: Framebuilding)

Date: Tue, 10 Oct 2000 16:18:50 -0400
From: Jerry Moos <moos@penn.com>
To: Hilary Stone <Hilary.Stone@Tesco.net>
CC: Classic Rendevous <classicrendezvous@bikelist.org>
Subject: Re: [Classicrendezvous] Hellenic stays ( Equilateral rear triangle)
References: <E13j50Y-0004SR-00@trolley.tesco.net>


A very good summary of the subject, I think. It appears that you do not necessarily disagree with Richard Sach's comment that the purported advantages of some of these designs, while they seem intuitively reasonable, might not withstand rigorous engineering analysis. I think it is a good point that relatively few engineers have worked in the bicycle business since the auto and aircraft industries became large and important. While I, like several on the list, have engineering degrees, mine are in chemical and electrical engineering and impart no particular insight into bicycle design. Even mechanical or structural engineers probably don't have much more insight, as most of the extensive tools, techniques and literature accumulated in that field in the 20th century were focused, as you so aptly observed in regards to manpower, on the much more economically important auto and aerospace industries. I'll bet there aren't more than a handfull of engineers in the world who would know where to begin to set up the engineering tests necessary to confirm or refute the structural claims of the classic British "funny frames".

If Trek public realtions pronouncements are to be believed, with all the stories of using wind tunnels and advanced CAD to design the US Postal team bikes, we are seeing a renewal of the application of intensive engineering to bicycles, though mostly to models far removed from the lugged steel ones of the past. Of course, it bears remembering that past attempts at high-powered bicycle engineering, i.e. Lambert, Exxon Graftek, and Teledyne Titan, produced in each instance a notably flawed product. Or, if Richard Sachs will forgive my plagiarizing his company motto "Technology alone is a poor substitute for experience."

Regards,

Jerry Moos

Hilary Stone wrote:
> I did originally intend my reply to go to the whole group and haver now
> posted to everyone.
> I would agree that most of the British framebuilders building funny
> frames went out of their way to build something different but there was also
> a clear intention to build a better frame to. The British magazine Cycling
> in the 1920s right through to the 1950s was full of technical articles on
> improving bike design written by so called experts. Unfortunately very few
> of these had any engineering background. This was also true of
> framebuilders. At the turn of the 20th century many innovative engineers
> worked in the cycle industry. By 1910 almost all engineers of any quality
> had moved onto the automotive or aeronautic industries which were far more
> exciting.
> Some framebuilders called themselves engineers but very few actually
> were. When a top rider came near to the end of racing career he as often as
> not opened a bike shop and began building frames or at least selling frames
> he had someone else build though often on the premises. Selbach, Grubb,
> Southall, Lawterwasser are just some examples. Others came into it through
> family connections ­ Baines, Bates and others were simply entrepreneurs ­
> Holdsworth, Claud Butler, Hyman Hetchins.But what they all shared was a lack
> of engineering knowledge. Framebuilding essentially is nothing more than
> slightly high tech plumbing ­ I can't remember who said that ­ it probably
> was Mike Mullett an English framebuilder who worked at Raleigh SPD and was
> partly responsible for building Zoetemelk's 1980 TDF winning frames and has
> also built until recently under his own name too. However it is essentially
> true. Wages were low so all sorts learnt to build frames. They all wanted a
> share of the market and so tried to build a better frame than the
> competition (in that they were egged on by ill-informed writers in Cycling)
> and one that stood out from the competition.
> Most of Britain's funny frames have already been covered in C+ Hetchins
> (not by me though), Bates, Baines, Thanet Silverlight and Paris Galibier.
> Taper tubed frames have yet to be done as have the Saxon short-wheelbase
> twin seat tube ones. But there are plenty more interesting Design Classics
> old and new to come yet.
> Hilary Stone
>
> Jerry Moos wrote:
> > Hilary, it seems from the phrasing this was intended for the whole group,
> > not myself
> > only, so I'm responding to the group, mostly so everyone will have benefit of
> your
> > thoughts, which are always of interest on such subjects. It's always
> difficult to
> > analyze human motivation, but I guess we all like to play amateur
> psychologist. As
> > an engineer, I know myself and my colleges always love to devise a totally
> novel
> > design, even when an objective observer would say that revising a conventional
> > design would serve as well. Looking at some of these classic British frames,
> I get
> > the impression their designers shared this attitude. While they may have had
> > functional improvement in mind, their handiwork seems to convey a delight in
> > approaching a problem differently than anyone had done before. This is also
> > combined to various degrees with pure ornamentation, the more elaborate
> Hetchins
> > lugsets probably being perhaps the most pronounced in this regards. In any
> case, I
> > think it is the evident passion for being not only better (at least in the
> > belief of
> > the designer), but boldly different in the process, that makes these bikes
> > appealing
> > and collectable. Your point about British makers providing a long list of
> brazeons
> > as early as the French is of course well taken, and gives the English builders
> in
> > this style, like Jack Taylor, an appeal very much like that of Herse or
> > Singer. But
> > it seems to me that is a much different appeal and perhaps attracts a much
> > different
> > following than the Hellens/Hetchins/Bates/Baines/Paris group. By the way,
> have you
> > already profiled all the significant unorthodox geometries in Design Classics
> in C+
> > (unfortunately, I've only subscribed since this past April) or can we look
> forward
> > to seeing some of these featured in future? Your column is among the best of
> the
> > many wonderful features in the best all round cycling publication in the
> English
> > language.
> >
> > Regards,
> >
> > Jerry Moos
> >
> > Hilary Stone wrote:
> >
> >> Jerry Moos' observations on Hellenic stays cannot be really sustained
> >> certainly in the case of the original design that was launched in the early
> >> 1920s. Lugs were exceptionally plain then Fred Hellens built what he thought
> >> would be a better frame. The age and the funny frame design and ornate lug
> >> was still far off.
> >> However before we dismiss all the funny frames we should take a serious
> >> look at the advantages of some. The Bates Cantiflex tubes do work
> >> exceptionally well at stiffening the main triangle to provide a frame that
> >> is comparable in steering accuracy to most modern top notch frames. The
> >> funny fork blades were added after as Jerry says to attract attention. Bates
> >> in fact showed another version of the Diadrant fork design before settling
> >> on the one used and because it infringed another maker's registered design
> >> changed to the one we now all know.
> >> In the 1930s there was a preoccupation with frame stiffness which still
> >> today many riders are obssesed with. One simple solution which did stiffen
> >> the bottom bracket was to decrease the length of the chainstays. Now I would
> >> argue that increased bottom bracket stiffness is not necessarily
> >> particularly important and that power losses at the bracket due to the frame
> >> deflecting are quite small but it doesn't take away the validity of chasing
> >> after a particular frame quality by a design solution that works. Shorter
> >> tubes are stiffer than long ones! Saxon (twin seat tube) and Baines (Flying
> >> Gate rear triangle) both went this way. And the reasonably wide spread use
> >> of tapered main triangle tubes mainly popularised by Granby and Selbach was
> >> also aimed at increasing bottom bracket stiffness. In fact virtually
> >> identical to Serotta's Corrado tubes and now St John St Cycles (Thorn) here
> >> in England are doing it with some of their top touring frames. Tapered tubes
> >> need to be looked for and are quite subtle so arguing that they are used to
> >> make the bike visually striking does not stand up.
> >> Furthermore whilst many of the French makers adopted internal cable
> >> routing (both electrical and derailleur) these are far from practical
> >> despite looking neat. Replacing internal gear cables is not a
> >> side-of-the-road job. Some makers in England were adding braze-ons for racks
> >> and derailleurs pretty much as early as the French.
> >> Hilary Stone
> >>
> >> > Harvey, despite Dale's valid points regarding structural advantages of
> >> Hellenic
> >> > stays, it is clear to me that this and many other features of some classic
> >> British
> >> > marques were primarily for visual effect rather than for whatever
> structural
> >> > advantage they offered. The Hetchins curly stays claimed to absorb shock,
> as
> >> did
> >> > the Bates diadrant fork perhaps, and the the Baines "flying gate" most
> >> definitely
> >> > shortened the wheelbase, though God knows what advantage one could
> attribute
> >> to
> >> > the bizzare geometry of the Paris Galibier. At the end of the day, though,
> I
> >> > think these designs mostly served to make the bikes visually striking and
> to
> >> allow
> >> > the builder to experience the sheer joy of implementing an innovative
> design.
> >> I
> >> > cannot believe there is any structural advantage in the most elaborate
> >> Hetchins
> >> > lugsets that could not have been served as well with a much less complex
> >> design.
> >> > This "over the top" ornateness constrasts sharply with Herse and Singer,
> where
> >> the
> >> > many unusual details (internal wiring for lights, cables routed through
> stem
> >> > cutouts, brazeons for brake pivots, lights, racks, etc., even early frame
> >> > couplings) almost all served some very practical purpose. Despite the
> >> "excess" of
> >> > the British designs I cannot help but find them "cool". I really must one
> day
> >> > acquire at least one example of this wretched excess.
> >> >
> >> > Regards,
> >> >
> >> > Jerry "Sometimes more is more" Moos
> >> >
> >> > Harvey M Sachs wrote:
> >> >
> >> >> Ladies and gentlemen -
> >> >> I guess my note got several people's goats, including Fearless Leader's
> >> >> (below) so I should try to calm the waters a bit.
> >> >>
> >> >> 1) Contrary to what a couple of folks inferred, I did not criticize or
> >> >> even comment on the lugwork. An argument can be made that elaborate
> lugs,
> >> >> particularly long points, make a difference in distributing stress, and
> >> >> they are handsome. I'm not a curmudgeon (usually) but didn't comment on
> >> >> the lugs.
> >> >>
> >> >> 2) Below I comment on Dale's notes about the "Hellenic" (I like that
> term,
> >> >> coming from Fred Hellen, as Dale pointed out).
> >> >>
> >> >> Starting the "gentlemanly disagreement," I wrote,:
> >> >> >Personally, I call them an affectation. For your trouble, here's what
> you
> >> >> >get:
> >> >> >
> >> >> >--> 2 extra joints to make and finish.
> >> >> >--> The joints on the top tube are likely on the thin part of the tube,
> >> >> >where most folks would prefer to use silver, but silver doesn't have
> >> >> >significant strength except in shear (as in a properly done lug), so it
> >> >> >isn't a really bright idea.
> >> >> >--> A much more awkward brake cable run. >>
> >> >>
> >> >> Dale responded <snip>
> >> >>
> >> >> >"that
> >> >> >extra work and care that these kinds of details require is actually how
> we
> >> >> >place higher values on small production, hand built bikes!"
> >> >>
> >> >> Gee, I thought it was for impeccable design and craftsmanship, a la
> Richard
> >> >> (no relation) Sachs and others. I'll include Hurlows and Clementines in
> >> >> that, and allow as some of my best friends love Hetchins (which I find a
> >> >> bit extreme, but that is taste and opinion, not facts).
> >> >>
> >> >> ><snip>
> >> >> >Dale: Actually you are technically correct in your points but I think the
> >> >> >description "elaboration" is better than "affectation.". Given that
> >> >> >description, it makes the feature ("Hellenic" stays?) a more appropriate
> >> >> >aspect of a bike like this.
> >> >> >
> >> >> >No question that the span of seat stay tubing that runs from the seat
> tube
> >> >> >contact point to the top tube juncture does relatively little in a
> >> structural
> >> >> >sense.. It just mildly anchors the points of triangulation.
> >> >> >BUT that Equilateral stay arrangement, by lowering the angle of the seat
> >> >> >stays, actually does have a few arguing points thus far left out... ;
> >> >> >- it allows more vertical compliance and therefore a more shock
> absorbing
> >> >> >ride than similar stays in a more vertical arrangement.
> >> >>
> >> >> Harvey: Offsetting that, the shorter stays are stiffer, so they might be
> >> >> less compliant.
> >> >>
> >> >> >Dale: - The overlapping of the stays at seat tube and top tube
> >> >> >limit/stiffen the
> >> >> >side to side compliance (albeit to a small degree) making the bike frame
> >> >> >climb and sprint with less side to side movement.
> >> >>
> >> >> Harvey: I bet you can't show that with conventional frame deflection
> >> >> gear... Not within margin of error. This is an unadulterated opinion.
> :-)
> >> >>
> >> >> >Dale: I personally have built using this "Hellenic"pattern on a few
> really
> >> >> >big
> >> >> >frames with shallow seat angles or frames for heavy riders on the theory
> >> that
> >> >> >they would best benefit from these subtle attributes.
> >> >>
> >> >> Harvey: I'm not a builder, but I'd be tempted, too, for really big
> >> >> frames. Esthetically, breaks up the big space in the "diamond."
> >> >> Makes the seat stays not look so much too loooong. Makes it look braced.
> >> >>
> >> >> Heck, Dale, I talk and you build. You're putting your money behind your
> >> >> bets. I'm just doing mind experiments...
> >> >> Harvey
> >> >>
> >> >> >http://www.cyclesdeoro.com/bigdoug1.htm
> >> >> >
> >> >> >Dale Brown