Lugged carbon frame... Is it safe?

on mine the carbon tubes are locked into the alloy ones- there are cutouts on the alloy tube where the carbon tube expands out, sorry for the rubbish description!

I'll try to find a photo.

think of how yourself is connected to the bike, your feet, pedals then bb axles. in terms of loads, the bottom bracket does not recognise the diff between pull or push. there will be torque and lateral movement within the bb. this, regardless on which way you're spinning.

think of how yourself is connected to the bike, your feet, pedals then bb axles. in terms of loads, the bottom bracket does not recognise the diff between pull or push.

exactly. specifically, I'm worried about the weave being designed for compression forces but not for a tension force on the drive-side down-stay. i'm not worried about generating excessive force (braking vs accellerating). Chance would be a fine thing if I could do either..!

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There is no such thing as "push" when you are talking about pedalling forces - you are either pulling the wheel towards you with the top of the chain or the bottom of it, at no point are pushing it. The chain would just fold up.

I once ripped the top and down tubes out of the head tube of a GT LTS. It was within warranty so GT swapped it over no problem. I sold it and bought the GT STS Lobo and then snapped that 2 months after the warranty ran out.

I'd be suitably worried about a carbon/ali frame from the early 90's.

I have a Giant 980C and have some bubbling of the clear coat around a couple of the lug attach points. I came across this thread using Google for any information about the issue. I can't find any product recall for this bike, so I'm not going to worry about a safety issue. Note that there have been recalls for 2009 Giant bikes with fork problems, so I know Giant is aware of recall procedures.

any bonded frame, aluminium (vitus) or carbon, i would stay clear of after 5+ years old

I have a trek 2300 composite bike from 93/94 and it's still going strong, don't have any issues with it.

any bonded frame, aluminium (vitus) or carbon, i would stay clear of after 5+ years old

Ernesto Colnago would probably disagree

I have a Giant 980C and have some bubbling of the clear coat around a couple of the lug attach points. I came across this thread using Google for any information about the issue. I can't find any product recall for this bike, so I'm not going to worry about a safety issue. Note that there have been recalls for 2009 Giant bikes with fork problems, so I know Giant is aware of recall procedures.

Steve, I don't think the bubbling is an issue, it's when you start seeing cracks is when it all goes wrong, You would probably get mixed opinions if you took it to bike shops but as far as I'm aware the american lugged carbon frames where over engineered (my Trek has an aluminium fork with a steel steerer for a start). Fire off an email to Giant and see if that bears any fruit.

Surely the force going into the rear triangle is the same as if you just had a brake on it? And since a decent brake can lock the wheel instantly into a skid, and that doesn't break the frame, why would there be any problems doing it with your legs?

I have a trek 2300 composite bike from 93/94 and it's still going strong, don't have any issues with it.

Ive got the same frame. - purple / blue. (trying to put a year on it.)
Run fine for year and a half.

Had the same question about an dynatech 725ti because of the glued tubes but thats running fine fixed too.

"is it safe?"

clove oil FTW

Surely the force going into the rear triangle is the same as if you just had a brake on it? And since a decent brake can lock the wheel instantly into a skid, and that doesn't break the frame, why would there be any problems doing it with your legs?

Not really, the brake is in a different position to the chain, so the forces applied to the rear triangle will be different when using a fixed wheels are opposed to a rim brake.

Ive got the same frame. - purple / blue. (trying to put a year on it.)
Run fine for year and a half.

Had the same question about an dynatech 725ti because of the glued tubes but thats running fine fixed too.

http://www.vintage-trek.com/model_numbers1.htm

here you go, looks like mine is actually a 92, half the components havebeen upgraded over the years, carbon forks going on it soon. Would like to get the paint off and polish up the aluminium one day like this guy has done. Looks sweet but a fucking mission.

Are you still running it with the sti levers? I had big issues with mine until I stuck in a load of GT40 and some lube and it was as god as new.