jliet

Hello, I know this question comes up a lot, and am not expecting a definitive answer, more for opinions from people who have seen more of the same situation possibly!

It's a Look kg481 frame, which I believe is constructed from Al lugs + carbon. The suspicious area is around the bottom bracket (expected stress area I suppose), but the fact it's on both tubes seems not so good. No flex in the area, and 'coin-test' sounds all the same to me pretty much for the area.

Thanks.

Moisture

I believe those are only superficial cracks in the paint, not the carbon itself. let's see who else chimes in.

shelbyfv

Never mind, not my job.

Crankycrank

Try sending some photos to Look as they may have seen some others with the same issue and may have something to say about it. Really you need to take it to someone who can see it in the flesh as a photo doesn't give you all the info you need to diagnose it properly. Could be nothing to worry about or the beginnings of the joints coming apart.

Barry2 

If I owned that bike,
and knew it’s history,
and I was a light weight,
I might continue to ride it.

But I wouldn’t buy that bike, too many other fish in the sea!

Barry

alcjphil

I see that you have a 57 cm frame. That is a very large size for that frame. I am 5' 10" tall and ride a 54 cm Look 481SL having found that a 55 cm was too big for me. The 54 cm has a top tube almost 56 cm long while the 55 has a 57 cm top tube. How tall are you? That said, the 481 and earlier 381 series are designed for a comfortable ride, at that time Look was sponsoring the Credit Agricole team and those bikes were their choice for the cobbled classics. The adjustable dropouts allow the mechanics to actually lengthen the wheelbase slightly for better comfort and slightly wider tires. What those lines in the paint look like to me are paint cracks where the carbon tube is flexing in the aluminum lug. I worked for a distributor for Look years ago and remember having to destroy a KG381 frame returned for a warranty issue. Our solution was to break the rear triangle by laying the frame on the floor and standing on the rear dropout. It took several tries. When it finally broke, the carbon stays did not fail, rather the aluminum bottom bracket shell lug broke. I doubt whether that frame is structurally unsound, just looks ugly with those paint cracks

jliet

I'm 182cm, but based on the geo chart found here, the top tube of the 57 is 574 (as opposed to 569 of the 55/56), and the measurements seemed closest to the bikes that I currently ride. Also, thanks so much, this is interesting to know - I assumed it could be the case with the flexing in the BB region and where the lug is, but it is also a 15 year old frame where I do not know the first owners history. However, great story about the destruction of the 381 and I guess that's the point of the most leverage aha!