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Evaluating "vintage" bonded frames (+ a specific question regarding one LOOK KG56)

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Evaluating "vintage" bonded frames (+ a specific question regarding one LOOK KG56)

Old 04-28-10, 01:12 PM
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Evaluating "vintage" bonded frames (+ a specific question regarding one LOOK KG56)

Hi all,

[begin anecdote] My eagerness for the past decade to buy into the steel revival has left me with little more than soundbites (carbon fiber will KILL YOU) when confronted with exotic materials. I've been getting softer on my hardline for the past year or so, have ridden and enjoyed quite a few aluminum frames, have lusted after some titaniums, and have in fact moved into a house with a random LOOK Generation 4 KG56 frame (sans fork) sitting in the basement. I can just hear it whispering to me beneath the floorboards. It tells me it knew I'd be coming around at some point. Well here I am, and my schooling tells me that if I even stand next to this frame I am liable to break a leg, or take a core sample of my liver or something.

So I let it sit for a few months longer. Finally the temptation took hold and I went down to give it a look see. Wow, me thinks. Not quite as light as I thought. Feels solid. A few paint chips here and there, looking good, looks close to my size, maybe I could ride this! ...but, oh wait, what's this...the paint on the lugs seems to be corroding. I remember hearing something about aluminum/carbon bonded frames from the late 80's / early 90's coming unbonded during riding...but wasn't that regarding Treks? Hum. Maybe I should take it by a few LBS's and get their opinion.

Here's their verdict. Three (all for profit shops) say "Hey, great find! Nah, that corrosion is only surface aluminum corrosion, probably from someone sweating on it during riding and long storage in the dank basement. Just tape off the tubes, sand off the old paint, and repaint with the fingernail polish of your choice! It'll ride fine." My pals at the local bike coop, of course, said "Man, what kind of chance do you want to take on a long descent with your frame? You have enough external factors to be worried about on a bike, 't ain't worth it."

Ah yes, conservative logic. I know it well. What kind of chance do I want to be taking? So I let it sit again.

But it's still whispering. [/end anecdote]

So I'm starting this thread to empower me and others like me to make quicker, more informed decisions during situations like this. What exactly do we need to be looking for when considering a 20 year old frame's lug/tube bonds and their integrity? Is the sweat story believable, especially if the corrosion is confined to the lugs and is not present on the tubes? Also, what about these paint chips? If they are only down to the primer, that's surely okay, right? What if some carbon is showing? I've heard that it's not much of a problem if it's small, just paint over it with some nail polish. Is that BS?

I hear many telling people that the only 100% sure solution is to examine everything with an ultrasound or x-rays or MRIs or this or that. I'm not looking for that, I'm looking for ways to distinguish between situations in which I need that kind of certainty and situations in which I don't.

Help me out here and I just might own my first non steel bike!
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Old 04-28-10, 06:11 PM
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It's the new thin walled, monocoque style CF frames that might "kill" you! So crispy fragile they are when confromted with forces perpendicular to their fiber grain, that frames can literally crack/shatter open when dropped against anything solid (specially at the seat stays). CF frames and other structural components are designed to have their fiber's weave run the direction of the forces going through it to make best use of the material's structural properties. So on these thin walled monocoque type CF frames, they tend to be most fragile when you apply forces to the sides of the frame members. Older CF frames are more robust and have thicker walls, so they do not have the same fragility at the sides of the tube walls as the new bikes do. Biggest problems that early CF/AL bonded frames had was separation at the tube junctions when the bonding glue fails for some reason or another. Even then, it's not like it was that common an occurance. Many early CF bonded frames are still on the road rolling up miles even after 25+ years, like my 1985 Vitus Plus Carbone 7.

As long as it was not abused or left wet too many times after a ride (as it will cause damaging electrolysis between the AL lugs and CF tubes, weakening the glue bond in between)
So don't be too afraid to enjoy riding the classic Look frame from the basement!......

Chombi

Last edited by Chombi; 04-28-10 at 06:17 PM.
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Old 04-28-10, 06:51 PM
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Ride it-show pictures also.
How many folks died in bicycles crashes/wrecks last year-800 or so maybe? How many were because the frame failed-zero probably, If you die on a bike, it will be because a car centerpunched you.Those bike coop folks are just "steel is real partisans"

Ride that bike-it is free, right??
Charlie

PS-Besides, on a really steep descent there is less actual force on the bike frame.Granted it is an inconvenient time for a frame to fail-going that fast and all.
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Old 04-29-10, 09:15 PM
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Originally Posted by Chombi View Post
As long as it was not abused or left wet too many times after a ride (as it will cause damaging electrolysis between the AL lugs and CF tubes, weakening the glue bond in between)
Chombi
Chombi, thanks for your reassurance. This certainly feels like a different tube construction technique than what I've felt on the so called monocoque frames of today. But I'm worried about you last qualifying sentence. Since I have no idea where this frame came from and cannot be assured that it wasn't abused in regards to dampness, are there any ways for examining the effects of this "damaging electrolysis"?

Thanks again
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Old 04-29-10, 09:51 PM
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Just in case for example the vitus frames sent to the states compared with the ones that went to south america had big differences in the bonding and forks for example.

I know roads are different here than in S/A but what we noticed back in the day was that the ALAN forks that came to the states were reinforced internally. The ones that went to S/A and maybe europe were not, so after a year probably the fork needed to be replaced after a nasty accident.

In my country and we checked experience with colombians, argentinians and brazilians and for them as for us all Vitus and Alans after 2 years max, in some cases like sprinters after 6 months some tubes were unbonded badly, the ones that came to the states were taking way long to have a problem in the bonding. Probably with the years the bonding got better but the american market is so big that many products have to come with better quality or the loss it is too big. Who cares about 100 frames per year market when in the states u sell thousands. so thats the market u need to take care off.


Good luck with that frame anyways, are good stuff...
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Old 04-30-10, 01:18 PM
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Originally Posted by JGatlin View Post
Chombi, thanks for your reassurance. This certainly feels like a different tube construction technique than what I've felt on the so called monocoque frames of today. But I'm worried about you last qualifying sentence. Since I have no idea where this frame came from and cannot be assured that it wasn't abused in regards to dampness, are there any ways for examining the effects of this "damaging electrolysis"?

Thanks again
It depends on the bike. From what I read about, at least for the Vitus and Alan frames, the damage from electrolysis is seen as black corrosion "tendrils" (on the bare polished aluminum lugs) coming from the lug/tube seams. I've actually seen this corrosion on a few abused CF bonded framed bikes through the years, looks kinda nasty and scary at the same time. Not sure how it will show up on Look KG type frames as I think the whole bike is painted(?) If it is, you might see it as bubbling or raising of the paint at those seams, but I would rather see what's under the paint if possible, to make a true assesment on whether any corrosion has occurred.
Maybe you should just take it to good bike shop that that have experience and sells Look bikes and frames and they can inspect it, .......although I'm always suspicious that a salesman would try to convince you it's toast and sell you a new Look frame instead.

Good luck and tell us how it goes with the "basement" CF bike!

Chombi
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Old 04-30-10, 02:35 PM
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I have two Vitus frames, one aluminum and one carbon. I don't trust the forks in either as a matter of policy. Around 1/3 of the joints on the carbon one visibly move and are toast. The aluminum one seems ok. Some day I'll take it apart and reglue the carbon one. Until then, I keep an eye on the aluminum one and let it get used.
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Old 04-30-10, 04:43 PM
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Originally Posted by jccaclimber View Post
I have two Vitus frames, one aluminum and one carbon. I don't trust the forks in either as a matter of policy. Around 1/3 of the joints on the carbon one visibly move and are toast. The aluminum one seems ok. Some day I'll take it apart and reglue the carbon one. Until then, I keep an eye on the aluminum one and let it get used.
My Vitus Carbone 7 is still solid as I got to really inspect the frame's condition closely, specially at the glue joints, when I restored it to what you see in my pic, last year. Just curious, what size Vitus Carbone do you have? Some noted that most of the glue release problems happened with bigger frames as there was more flex at the joints with the long frame tubes. Mine's small at 52CM. One thing I did notice was, there seems to be quite a bit of aluminum from the lugs going into the tubes, so, the joints seem to have been engineered to be strong and will most likely show signs of loosening first,, way before failing completely.
Did you notice any glue problems with your Vitus 979 forks too??

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Old 04-30-10, 05:58 PM
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Not sure and I don't have a tape on me. The carbon one fit my uncle who is 5'8" to 5'10". The aluminum one is tiny, I think a 48, but I'm not 100% sure. I haven't seen any glue issues with the 979 forks, but I'm not really inclined to trust them.
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Old 05-01-10, 07:44 AM
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Originally Posted by Chombi View Post
As long as it was not abused or left wet too many times after a ride (as it will cause damaging electrolysis between the AL lugs and CF tubes, weakening the glue bond in between)
I can't vouch for other manufacturers, but the original Trek bonded carbon fiber frame had insulating fiberglass sleeves in the joints to prevent electrolytic degradation.
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Old 08-26-10, 11:07 AM
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I'm looking at purchasing a guerciotti bonded carbon bike.I know there is some issue with it. The entire headtube has been covered in black epoxy. Everything else looks sound. Even that part looks great and seems to me that it should only be more solid than before. I think I could get my money back on it by parting it out but I'd like to ride it. Does anyone have an opinion? I'm probably going to try to get the guy down to a price I'm more sure of parting it for. If I get it I'll post some pictures for more opinions.
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Old 08-26-10, 02:44 PM
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Originally Posted by Chombi View Post
. . . like my 1985 Vitus Plus Carbone 7.
Chombi
Beautiful bike.
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Old 08-26-10, 09:04 PM
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Originally Posted by JohnDThompson View Post
I can't vouch for other manufacturers, but the original Trek bonded carbon fiber frame had insulating fiberglass sleeves in the joints to prevent electrolytic degradation.
My '91 Specialized Allez Epic also has the fibreglass insulating later. However, the previous model years didn't and some of them fell apart.
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Old 08-26-10, 09:17 PM
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Originally Posted by DannoXYZ View Post
My '91 Specialized Allez Epic also has the fibreglass insulating later. However, the previous model years didn't and some of them fell apart.

Some of the earlier Vitus Carbone frames suffered from joint failure (that sounds like a Cheech & Chong joke...). I've seen a couple that had separated at the seat tube/BB joint, but that was 20 years ago. They were glued back together with a special epoxy. I seem to recall that a couple places were authorized Vitus repair centers- Harry Havnoonian was one and they say they repair bonded frames: https://www.hhracinggroup.com/page2.html
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Old 08-26-10, 09:31 PM
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I used to own 2 AlAn bonded frames .. If Iwas on the Italian side of the Atlantic .. great .. repair and partial replacement was cheap.

but its the getting the carton with the frame in it that had me sell one and walk away from the other .. measured carton as air freight was like it weighed 55 pounds when actual weight wasn't 10.

anyone want some Campag super record 1 bolt 25.o seatposts got a USE 25 to 27 and 27.2 shims as well ..
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Old 08-30-10, 09:08 AM
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Said I would post picts if I bought it so I did but in the C&V value forum. Under Guerciotti carbon take two.
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Old 08-30-10, 10:20 AM
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If you really want to know,you can pressure test the frame.Block off the frame and put 20 lbs or so of air in the tubes,squirt soapy water on the joints and have a look.Leaking joints are loose,have voids,wormholes,ect.
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