cudak888 

Three-piece construction with a steel center - 1950's?

It reminds me of a Fratelli Brivio but that smooth domed shape of the flange is throwing me off, and FB didn't have that either. Looks almost like a 1950's idea of what a C-Record hub would look like

-Kurt

Kuromori

You know, I imagine it would work decent enough. As far as I can tell, the primary purpose of the drop parallelogram is to shorten the distance between the A/B pivots while maintaining a reasonable linkage length for the parallelogram. When these designs first started appearing, there was a pivot bolt that went all the way through the A/B knuckle, so one of them had to be offset and the blind pivot design only came later. The Athena RD uses a blind pivot so it can be behind the linkage plates, so you still get the shorter A/B distance. The Suntour XCT is of a similar design as well.

cudak888 

Shorten the distance, or keep the distance more uniform with the freewheel? Part of the problem with the straight paralleogram design is that it effectively pivots the entire pulley cage closer to the freewheel as the cogs get larger - thus the pulley cage and upper jockey wheel need to pivot too far backwards for crisp shifting, just to clear the cogs.

What I think I see in the Athena's engineering is that the blind lower pivot allowed the pulley cage to be brought closer to the cogs, and the angled parallelogram pulls the derailer rearwards, so to move the upper jockey wheel backwards, roughly in parallel with the increasing cog size. At least, that's what it looks like it's trying to achieve; in practice, it probably just doesn't wrap as much chain as ideal, specifically because of this.

-Kurt

vintagerando

Bottom bracket shell is stamped EDA

Kuromori

I still think the primary purpose is to shorten the distance and counteract the cons of a long A/B distance. What you're talking about is partially remedied by making the RD swing in both directions from straight, something fairly typical on Shimano designs, rather than just inwards. The part of the fix from a drop parallelogram you're talking about is making the linkages more tangential rather than radial relative to the cogs. This also helps but is still not a full fix which is probably why Shimano did both. Again, I think this is an issue of length. You could make a straight parallelogram closer tangential in a similar way, but it would require the hanger to be considerably further back than where a standard Campy hanger is, which probably explains the designs of some Shimano Tourney RDs. Given how chains load the sprockets mostly on the first few teeth, I'm not convinced maximum chain wrap is that big a deal given that most of the load is carried by the first few teeth.

This is getting rather off topic though.

Chombi1 

Is there such a thing as a jig that holds down a frame and then use small hydraulic rams and tube clamps to straighten bent frames like these. Just like the do with cars today, but at a smaller scale for bicycles.
It is just sad when a slightly bent frame is considered toasts by many when it can maybe be bent back straight.

T-Mar

Campagnolo's official claim for the LOS (Lateral Operating System) design of the Athena derailleur was to maintain a constant chain gap. They didn't even mention indexing in the literature for the Athena rear derailleur but LOS was obviously an attempt to improve indexed shifting performance. Their previous designs did not work well as indexed derailleurs and this was their one of their solutions. I say one because they used an entirely different approach with Chorus. At the time, it seemed that Campagnolo didn't have a firm grasp of indexing and was using the multi-pronged approach to see which one won favour with the public. They would eventually standardize on a Shimano clone.

jdawginsc 

That chrome bike would be cool as a wall hanging, but it should be able to be straightened...it really is a beauty.

unworthy1

Very interesting and well worth the $20 spent, especially if you like a "project"! I' would have been guessing "British" based on the wrap-over stays and might have thought a Haden or Davis forkcrown...but now not so sure. What's the BB threading?
Still might have had a fork replacement after a front end whack but it looks like it belongs, except is that a recessed front brake and (I assume) nutted rear brake? "EDA" BB shell is a bit mysterious, I recall the brand only faintly, similar markings to the RGF (French) but was this another marque from somewhere like Belgium? Anyhow that brand was MOSTLY used by FR brands, but Raleigh used them on some frames as well so the threading will tell

madpogue 

Andy @ Yellow Jersey straightened out a top tube bend in our '75 (?) Gran-dish Sport-sish 531 frame, similar to the one above, perhaps a bit more severe. Did it all "cold", zero damage to the finish, less than a Franklin.

vintagerando

I like what I am reading......thanks. I had give up hope, frankly.

vintagerando

The BB thread is English. The BB shell is stamped "EDA" (havent researched it yet). The bottom of the BB is marked "R A M" which I think could be the frame builder, maybe?? No idea. Or maybe the original owner of the bike? It looks DIY, like someone did it at home.

Kuromori

The big problem with repairs is it costs money, often not trivial. It can add up if you have to send it to a specialist on top of high specialized labor rates, often more than the cost of finding another used bike in good condition. This is often true of most frame repair.

EddyR

I straightened a few frames a number of years ago. I clamped the frame to a very I heavy bench an put a pipe through the head tube. I jacked from the bottom bracket to the pipe and the bend came our. the pipe has to be thick to take the pressure. I made holes in pipe to mount jack an head tube. It takes a huge amount of pressure to bend frame back. I tried it with out the jack and could not get leverage. There are tools to do this.

unworthy1

OK, based on this I'm solidly guessing "British" but could hedge just a little for "Dutch" only since I'm not 100% solid... and not sure who or if the RAM initials mean builder or owner (as you suspect). When you get the fork off see if there are any clues on the steerer. Is it a recessed bolt brake front and nutted brake rear?

vintagerando

Yes. Recessed bolt for both front and rear.

There is a clue in the "EDA" stamp on the BB. I searched it and I believe its French.

vintagerando

BB stamps

cudak888 

I found one reference to an "EDA" bottom bracket on a Mercier, which this isn't. Methinks that might be the stamp of the BB manufacturer.

https://velospace.org/forums/discuss...unknown-breed/

EDIT: Posted this before @vintagerando put up the BB pic. EDA definitely looks like it's from the lug manufacturer.

Are you sure the stamping on the BB is supposed to mean "RAM" and not "R^M?"

-Kurt

cudak888 

Provided this thing isn't 753 (and despite the recessed brake mounts, I doubt it), I bet you anything that it'd straighten out with a Park HTS-1, and if not in an HTS-1, sticking the headtube in a solid rod and yanking up on the chainstays ought to do it, as brutal and unscientific as it sounds. I recently straightened out a Super Grand Prix this way to marvelous success.

Part of me wants to throw "Flying Scot" out there, but I don't know of any with that secondary loop on the chainstay for the derailer cable.

-Kurt

t_e_r_r_y

i'd be worried about ovalizing the headtube doing something like this :O

cudak888 

You have to leave the headset cups in. Sometimes a good idea to put thick, cheap cups (if they fit) in place of any nice headset cups for this.

Last time I did this, I used a cut-off, solid stainless propeller shaft out of a boat. Fit really snug in the cups, so the force was spread nice and evenly across the cup edges.

At any rate, there isn't much to lose by trying.

-Kurt

t_e_r_r_y

that makes sense!

vintagerando

Well the serial numbers on the frame and fork match. So, the fork is original.

cudak888 

If the serial is anything to go by, potentially a more mass-marketed frame than we might think. #385 of 1969, perhaps?

That assumes, of course, that the fork and rear bridge were drilled. Do the recessed mounts look factory? If so, perhaps we're dealing with a newer bike than my mind would like to think it is.

Wearing myself out checking chainstays at Classic Lightweights...

-Kurt

cudak888 

Ran into one possible close match, and one less probable:

Wally Green - RD cable guide, wraparound stays, exquisitely finished Nervex lugs (and it seems as if the edges have been removed), but a flat fork crown:


Stan Pike - same fork crown, wraparound stays, no evidence of building with Nervex though, and the derailer cable guide is spaced further away from the stop: Stan Pike Cycles - A site dedicated to the legendary frame builder

Take this with a grain of salt. I'm guessing, and I'm not convinced of either.

-Kurt