Joe,
I'll agree that Campy horizontal dropouts often break in the horizontal section just in front of the raised portion. I've replaced a few of these as well. However, that's not what Jobst was referring to. He never mentioned broken dropouts, so I believe he was implying that it is the geometry of the dropout slot that caused axle breakage. It is my opinion that the Campy horizontal dropouts broke because of a design defect that resulted in a stress riser at a critical place. The problem could have been aggravated by poor brazing, as the point is a suspicious distance from where heat is applied at the chainstay/dropout connection, right where the heat gradient may result in crystallization. I wonder if any other long-time framebuilders have a sense of whether or not they have seen much of this breakage on top-quality frames, that we can be fairly confident that the brazing was done correctly?
At any rate, I don't think that a Campy dropout that is about to break flexes any more than one that is sound. The metal doesn't get more flexible as it approaches failure. Personally, I haven't seen the correlation to which you refer in broken Campy rear axles accompanying broken Campy rear dropouts. I wonder if anyone can collaborate your experience?
What I meant by my misspelled reference to empirical evidence was, has anyone actually measured the deflection of an axle under the stresses applied by riding with horizontal vs. vertical dropouts? Or, is this just something that seems to make sense to someone with an engineering degree, then promoted as fact? The biking press in the '70s was full of articles like this written about wheel lacing patterns, frame details and any number of other subjects; many of them by our friend Jobst. It all made sense and made one look studious and cool when they could spout these "facts" in the isles of the bike shop, but was there any real fact involved? Any true testing? I think the vocabulary far exceeded the science. Personal experience is as equally lousy a lens as quasi-engineering conjecture, as it is a limited view, typically biased by any number of other factors. I think the best measure is the impartial pooling of experience of a large group of involved people, such as this list. That, and actual testing. I love the quote in the Sutherland's manual, "One measurement is worth a thousand expert opinions."
Steve Barner, still have the torches and the rosebud in Bolton, Vermont, and there's still gas in the tanks--in more ways than one! ----- Original Message ----- From: Joe Starck To: Stephen Barner Cc: classicrendezvous@bikelist.org Sent: Saturday, August 16, 2003 5:07 PM Subject: Re: [CR]Re: Vertical dropouts (was some dates please and Asps)
Steve asked, "Anyone know if there is any empiracal evidence to this belief that horizontal axles result in higher incidence of axle breakage?'
Steve - Typos above aside, the most common steel dropout I've replaced are horizontal (1010B I believe) ones that had cracked just shy of the face. That I've replaced more of this type than others is due to what? -- 1. There are more of them out there? 2.These types are found on frames worthy of the repair? 3. They lack the transitional reinforcement more commonly found on Shimano or Shimano-like vertical?
And as to axle breakage, does the weak, weakened, or broken dropout cause the axle to eventually break? -- Or visa-versa? -- as the two problems present together at most times in most repair shops.
So Steve, has this all been hashed over before here and/or what does it all say about the empirical evidence of the gods' preservation?
- Joe Starck, Sun Prairie, Sun Prairie
Stephen Barner <steve@sburl.com> wrote: Never one to hide my propensity to be a rube by refraining from taking a hammer to the feet of the cycling gods to test for clay content, I again look askanse at Jobst's logic. Anyone know if there is any empiracal evidence to this belief that horizontal axles result in higher incidence of axle breakage? For that matter, anyone ever even HAD a major problem with axle breakage on Record hubs? I don't dispute Jobst's claim of having introduced vertical drops to Cinelli, but this claim of axle breakage leaves me skeptical. The places where I have seen breakage as a problem are primarily with misaligned frames, or hubs run loose. For horizontal dropouts to be a problem, there would have to be a slight flexing of the axle in the fore and aft direction. One would think that this rocking would be visible in the indentations on the inside of the dropouts, but that is not the case, at least as far as I can see.
Does anyone else have experience that would support Jobst"s claim, or might he again be confusing engineering daydreams with reality?
I have always wondered why the vertical drops did not have raised faces for the axle. I have seen Japanese verticals with an extra layer spot-welded or brazed on to thicken the dropout. I thought builders stuck with horizontals because they were more tolerant of slight misalignment, at least in one direction, and they usually result in better chain wrap, as the dropout hanger is farther forward and usually closer to the freewheel.
Steve "just ride the damn thing and stop jawing about it" Barner, Bolton, Vermont
----- Original Message ----- > Date: Fri, 15 Aug 2003 10:48:34 -0400 > From: "Silver, Mordecai" > To: "Classic Rendezvous" > Cc: mountgerald@btopenworld.com > Subject: RE: [CR]some dates please and Asps > > Mark Stevens wrote: > "Can anyone tell me when Campagnolo introduced their vertical rear > dropouts?" > > Jobst Brandt claims to have introduced vertical dropouts to Cino > Cinelli, then to Tullio Campagnolo in 1960. He had first seen them on > Diamant bicycles at the 1960 Olympics in Rome. > > Jobst has mentioned this recently in rec.bicycles.tech. From his post > of June 3, 2003: > > "Paul McKnab writes: 'On a Merckx steel frame there are two screws built > into rear dropouts of the frame that adjust how far in the rear axle > will travel when inserted. I know that the screws can be used to adjust > the wheel's left/right positioning so that the wheel is true with the > frame. Here is the question: the screws can also be used to determine > how far in the wheel/axle slides. What determines that correct > distance? How far in is too far in and how would I know?' > > It was these screws that got me to introduce the vertical dropout to > Cino Cinelli and he subsequently to Tullio Campagnolo. Those screws > were leftovers from fixed gear riding that the old timers felt was > essential to early season training, never thinking that they were doing > this because derailleurs were so clumsey and unreliable. By the time > the Campagnolo Gran Sport came along the horizontal dropout was an > anacronism but it would not go away because there were still a bunch of > old timers who swore by them. If we did it, it must have been right. > > The longitudinal dropout also was a major cause of Campagnolo axle > failures because the jam nut is unsupported in the fore and aft or chain > tension direction. Chain tension is about a four times greater force > than rider weight because it has about a 2:1 ratio at the crank and is > concentrated on one side of the axle. Those dropouts bugged me from the > first day I worked with them. I was glad to discover vertical dropouts > on Diamant bicycles at the 1960 Olympics. That was the end of axle > adjusting screws for me." > > >From his post of November 14, 2002: > > "I didn't introduce Cinelli and Campagnolo to vertical dropouts in 1960 > for nothing...When I saw Diamant (East German) bicycles at the Rome > Olympics with vertical dropouts, I made some in the local shop and gave > them to Cino Cinelli for my next bicycles. I've been using that kind > ever since." > > >From his post of May 31, 2002: > > "Rear axle failure on Campagnolo freewheel hubs was a common occurrence > before vertical dropouts that practically eliminated the problem for > those who still ride these antique hubs. > > I had the first 'Campagnolo' vertical dropouts made in 1960 after seeing > them on east German bicycles at the Olympics. I gave four pairs to Cino > Cinelli for frames I had ordered and he gave one set to Tullio, an old > friend. The next year we saw the Campagnolo version in production." > > Mordecai Silver > New York, NY > > p.s. What a night it was! No power in New York City, commuters camping > out on benches in Bryant Park. No traffic lights -- I was riding my > bicycle home at dusk, and it was pretty weird!
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