Really.

A guy came to look at a 1988 Centurion Ironman Carbon. Tubing glued into alloy lugs. Alloy fork, which is pretty flexible. He likes everything about it, but is concerned about durability. It is running Bontrager Race wheels. If it was steel, he'd be riding it now, I've no doubt. I'm clueless as to whether it would hold up.

Pro: I'm 6" shorter, and 70lb lighter, but I'm probably slightly stronger than he is, and I've really pushed the frame, with no problem.

Con: He's definitely going to apply more leverage, it's 21 years old.

All input is appreciated.
I've had sellers and bike shops refuse to sell me certain frames (Trek OCLV carbon and the Trek 1200 when new) for fear of me breaking them.
Maybe I just look clumsy, I dunno.

Now I'm on the other end, and clueless.

You want an objective opinion - here - from us lot, good luck!!!

I have no idea how much you weigh or how tall you are, but if you are anywhere near normal size then a guy 6" taller and 70# heavier is pretty damn big. Since we do not yet have enough years of carbon behind us to know how long it will last, and the frame is over 20 years old already... I wouldn't say he was being unreasonable. Over cautious maybe, but not unreasonable.

One huge Fred stomping on a small gear uphill is exerting more force on the frame than a pro sprinter. And we can count on that pro to land gently off of curbs and not stomp the landing.

Campy only rates their components for road use by riders under 185 pounds. I'm a lot heavier than that and ride cross with the stuff but they do know their gear.

If someone declines to take your money, I'd usually take his word for it.

You probably have like minus 10% body fat and the buyer has plus 40%...

Well, I have no experience with carbon road bike frames, but I got a trek Y frame ATB years ago. I think it must have been a '97 in '98. Whatever was the last year they GLUED on the rear shock. I wanted that bike so bad. Anyway. In about two years it sheared. I never abused it more than normal ATB abuse. I don't know how to describe the shear but it was sorta where the downtube would have been above and infront of the crank. It was very visable and you could feel it on the bike. As far as I know I never hit it on anything sharp there. At least I got the bike cheap. The mechanic said he figured it was my size (not huge, 200ish 6' 2") combined with his insistance that I must have kept it in sunlight which he said would somehow weaken it or something. I don't know if I did. I kept it inside, though.

Anyway. It did fail, but not catastrophically. I just got on it and went off a curb and it rode all wrong. LBS said I was lucky it didn't break during a drop or something. It scared me away from carbon, though I don't think I'm "scared" of it anymore. I think perhaps the earlier carbon frames weren't as well built as they are now. Though I don't know if that frame shape was actually better than a diamond in carbon. I guess I would just be cautious, but at the same time I do know people who have beat up carbon framed bikes and not broke them.

I guess I can sympathize with the guy, I don't think he's unreasonable. Really is a pickle. There's no way you can know if it will or not, as was already implied. Is he waiting on you to say it will last foury more years, then he'll buy it? Otherwise no sale? Sorry to not really be helpful. I suppose I'm non the "carbon cautious" side of the wall.

edit: wow, I was looking for a picture on google similar to how my trek broke and found this (most is crash damage, which is irrelevant, but some is fatigue):

https://www.bustedcarbon.com/2008_11_01_archive.html

I know we could probably find even more pictures of broken metal frames, but maybe this is slightly relevant? Maybe carbon is just too fine tuned for the rougher, heavier riders?

I try never to talk buyers into a bike. I present the bike, let them take a ride, and make their own decision. Sure, I talk up the condition and components of a bike, but the ultimate decision is the buyer's. For some reason, he is considering/looking at a carbon bike.

If you have a steel bike, you might show him that and talk up the benefits of steel. Its always helpful to have multiple sizes available.

To me, he does sound too heavy for a glued carbon frame. You might want to try the Clydesdale list.

So what do you think the guys actual weight is? The key question is the bonded lugs, if it was a straight CF frame I don't think the weight would matter, just the wheels.

Maybe I'm missing something, but why is this your dilemma? I think you have presented the seller with the facts about the bike, including your honest opinion about its durability. It is up to the buyer to decide if he wants it or not. If he buys it and breaks it how is that your fault?

^^^^
bingo

Plus - how is it that a guy 6 inches taller than you rides the same size bike?

Because Robbie is not the type of guy to sell something to someone if he thinks there's a good chance it's gonna break on them. Personally, I find that admirable, but then bikes have never been a business to me, even when I'm selling one.

Robbie, As you know, I'm just over the Clyde limit (well maybe, I've lost a bit since we last met a few months ago). I've ridden glued frames, and had no problems or concerns. I would have no concern about riding a vintage carbon frame because most of them where over-engineerd to assure they would not fail.
However, if your buyer is concerned about frame failure, let him move on and sell it to someone with confidence. I say that because if the dude has doubts, any problem with the bike could turn into an excuse to complain or return the bike.

I am not sure how big of factor weight is here. I have seen both large and small glued frames fail. he has a 50/50 chance. and as far as that goes if you sold him a steel bike, unless you repainted it you never know right?

My error, sorry. He's 246 lbs, about 6' hence his concern about the frame holding up.

I think he's absolutely being reasonable. Otto Rax used to own the frame, and he's probably around 6'2, 190, a little taller but a lot lighter then the prospective buyer.

I have no dilemma. I honestly couldn't answer his question, and here's where I go for answers.

If I don't know myself if the bike will hold up for him, I sure don't want to try and convince him it will. I've had the benefit of cautious sellers not wanting to sell me a bike for the same reason, now find myself on the other side of the equation, and am simply clueless, so I turn to BF.

I consider anyone who buys a bike from me a potential friend, a person to ride with someday, and someone I hope will get into cycling and stay with it. I'd much rather have him buy a different bike and love it than buy mine and have it break. I can't go ride with him if he doesn't have a bike....

Um, freak of nature. The frame measures 60cm from c of bb to top of top tube.
I'm 5'6 and ride it all the time. Some of you guys have ridden with me, like roccobike.
It just works. Riding is fine. Standing over is out of the question.

All,

I appreciate the responses. I'll contact him and tell him I am 50/50 on the frame/wheel set combo being right for him. I can probably go to Ksyrium Elites on the wheels and he'd be OK there, but I think the frame's a little iffy, and I definitely know the fork is twitchy.

Since the thought of him on a steel frame raises no such doubts, I think that's his best option, and I'll tell him so. He's a nice guy, and I think he'll like biking, once he's properly fit on a good bike.

Thanks for everything, folks.

Even steel has rider weight ratings. Unless he plans to lose some of that weight, he'd probably be best off with straight gauge on the smallest frame he can ride.

Of course, there's probably some margin of error on the weight ratings, and the frame may never fail, but the worst that's likely to happen with a steel bike being ridden by somebody over its weight rating is the frame will eventually fail, although most likely the failure wouldn't be of the catastrophic variety...

Agree that everything built has a failure point, but that doesn't mean it has a rating. There might not have been a practical reason to rate it.

I don't know with certainty that all tubesets have rider weight ratings, but Tange tubesets definitely do, and I would be somewhat surprised if that wasn't true for tubesets from other manufacturers.

but when carbon fails it usually shatters/shears/breaks and while steel will most often just bend (assuming were talking better frames where the brazing would be good)

I've contacted him, and recommended a couple of newer bikes in his price range, set up the way he wants, so he can train and ride a 75-miler this fall. And I'll keep a look out for a good steel frame for him, probably a 60-62cm.

Ends. He bought a Scott Speedster, and loves it. 60cm.