cracked lug
 

Recently acquired this Atala Grand Prix and was going to use it as a grocery getter but now I'm not sure that it is safe. I'm well aware that the brazing and craftsmanship of these frames tends to suck, still I'd like to use it. So there are two areas of the frame that are compromised and I thought I'd get the opinion of some experienced framebuilders so as to be somewhat safe. The lug is the lower headtube lug attaching to the downtube. There is also a crack of sorts that appears original to the frame on the rear seatstay. Do these cracks render this frame unusable and graveyard bound or is it still rideable? If it's a repair that is needed, I hope it's a really, really cheap one, otherwise I guess I'm on the hunt for another affordable Italian frame.

That really doesn't look like a crack on the lug to me. It looks like the original construction was with super plain "hosepipe" style stamped lugs, and they added "ears" on them to make better looking lugs. I might be wrong, but that's what it looks like to me, and what you're seeing is them (very) imperfectly joined, and the resulting seam. I'd just ride it and keep an eye on it.

I can't see anything on the dropout, but the pic is sort of dark and isn't showing up very well on my laptop.

http://bikeforums.net/attachment.php...hmentid=271400http://bikeforums.net/attachment.php...hmentid=271401http://bikeforums.net/attachment.php...hmentid=271402

Here's some better photos...

that wasn't a cheap bike when it was new. Should have been.

I don't know what to say about it. The seat stay is a utter horror story, can't believe they shipped that. The lug had a welding flaw, and they just let it go. Pressed lugs like these were made out of flat plate, shaped, and then welded down the centerline. That is the weld that wasn't completely made. There does appear to be a crack emanating from the welding flaw. I don't see how it would crack like that unless they didn't fully insert the tube into the lug -- which is entirely possible in this case.

I see what John is saying above, but I don't think it is an add-on, unless they filled a window.

I meant to say, I would probably ride it around town and keep it clean

thank you for the feedback

My first ten speed bicycle was an Atala Gran Prix and the entire unit cost less than $80 new. You
can't expect much from a factory made frame whose production never went past 1974. In short,
it doesn't owe anyone anything, and you get what you pay for atmo.

I'd have agreed on the extended lug design theory, until I saw 009.jpg. If that's two pieces of metal butted and badly welded, the root of what appears to be the crack is the end of a shoddy weldbead, then why is the joint/crack not even slightly perpendicular to the centreline of the tube? But then, what the hell leaves a crack initiator like the blow of a morning star, in a lug?

questions I ask myself as well

http://www.bikeforums.net/attachment...1&d=1346934779

I wonder if what we're seeing is a tube that was not fully inserted into the joint prior to brazing, leaving the lug to support the stress at the joint, with a crack appearing at the point where the end of the tube lies under the lug?

Time to break out the hack saw and find out!

I think all questions are answered by the picture of the seat stay. There was no fault too big to stop this train from leaving the station. When this was built, dealers were screaming for bikes, it was crazy. $80 is probably $1000 now, these really weren't that cheap.

I have seen pictures of bikes like this where the tube wasn't all the way inserted, but they usually had a miter on them. So having a tube with a square end would be somewhat unexpected.

Do we have to take up a collection in order to get this thing cut up?

oh man.... too funny, if we can reach the target goal of 500 smackers or one high end Italian frame 62st 58tt then the hacksaw comes out

This Gran Prix model was a low level Atala even when it was new. Bike boom or no bike boom,
the $80 I paid when new was not a lot of money atmo. I'd wager that it was machine brazed
rather than assembled by a man or group of men on a factory floor.

What Unterhausen is saying is that price is irrelevant, corners were cut in the heyday of pathological bicycle demand, just as they always have been with the car industry (even more, ironically, now, when we know we shouldn't, have all these years of design experience and empirical materials knowledge... but don't get me started on Ford Europe hehe). I'm not sure that's actually an unnoticed fault, as an intentional 'design feature'* at the seatstay-dropout joint.

If the toptube hasn't met the seat tube in that lug then I'd expect the crack to be a different geometry, too, unless some cretin cut the tube off square. And there's not quite hitting the bottom, as opposed to only poking it in halfway, as the bishop said to the actress. That should be reflected in the rest of the main triangle angles being off kilter, because nothing would fit right then.

Has anyone got access to an X-Ray machine? I never felt comfortable with destructive analysis...


*not a bug ;-)

not that it matters, but researching the conversion of the currency, I'd say 80 was roughly 350 in 1972, pretty cheap bike, of course Bicycling Magazine's review in 1974 priced it at 154.95 which sounds closer to 600+

JohnDThompson - I suspect you may be onto something.... At best, I would recommend pulling out the fork and try to examine it by shining a light up the bottom of the headtube and through the hole that would normally be in the head tube. If one sees the edge of the tube or a surface that looks like the inside of a lug, then I would crush the frame and recycle it. But if one sees what looks like the inside of the downtube going pretty much up to the headtube, then it it is probably ok and the theory of a welded/cobbled up lug gains ground. A clever person might find a friend with one of those snake "inspection" tools like they sell at a hardware store. It would give a better view inside. If there is no hole in the headtube then I guess one could put the Dremel tool to work but it would be easy to get too much invested in this frame which look pretty low quality to start with (poor filing, etc).

Boneshaker78 - Just hazarding a guess on the seat stay aspect... It almost looks like one of the old seatstays that were spit on the small end to all a drop out to be fitted up into it. Now in a rushed build where one mitred the stay for the joint up at the seatclamp before realizing that the tube was rotated 90 degrees off... so the worker just slaps it on the saw and cuts a new slot??? Running in a little additional brass to fully fill up the gap would have hidden the goof... if they had cared (which is not evident in most of the frame)

I was wondering that too.

there was a thread on another forum where a framebuilder cut up a batch of lugged bikes from the same era as this bike came from. There were all sorts of problems, but it was common to have the tubes only partially inserted into the lugs. With a lug like the one on this frame, the tubes might not even be mitered.

I just realized I have a Grand Prix frame hanging in the workshop. The tubes are mitred, but crudely, and the head tube is a one-piece bulge-formed unit. E.g. here's the HT-DT joint:

http://www.os2.dhs.org/~john/atala-ht-dt.jpg

If the tube on the OP's frame wasn't fully inserted, I think it could lead to the type of crack seen on the lug.

Perhaps the OP could pull the fork on his bike and take a look?

Shined one of those snake lights up there today, although it was hard to see I do believe that the tube was not mitred or inserted all of the way, I can clearly see a gap. Mystery solved but I'm still tempted to ride this sorry beast. Any opinions? just too dangerous, not worth it, give it a go and monitor the crack, start another thread testing the remaining integrity of this sad POS.

I can't recommend riding it, and I refuse to ride a bike that I don't have complete confidence in. Having said that, the crack is likely to grow slowly.

Sell the steel as identified alloy, with surcharges, to a reputable scrap dealer.

Chrome plated steel wont even Tig weld without grinding off the plating first.

a lot of shiny frames were cranked out to meet young Boomer demands back then..
numbers demand got QC pushed down on the priority list

First time wandering into this part of the forum, and I used to love taking scrap parts from car projects and turning them into things.

Perhaps snake some wiring in it and turn it into a weird chandelier? Or put lights that you can aim, hang it flat on a wall and point it at something like reading lamps or to light up art work?