So I was following all of the instructions. I mounted the front mech to the braze-on mount. I put the little metal sticker on the frame. Then I was tightening down the support bolt, and I heard a "crack!" I took of the derailleur and looked at the frame. I don't see any cracks or damage. I don't know whether I cracked the frame, separated the frame from the braze-on mount, or it was just a noise and it's nothing to worry about. Any way to be sure?
Problem installing 6800 Front Derailleur FD-6800
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I didn't tighten it very hard, but that's a pretty subjective statement. Also, that tiny metal plate is supposed to protect the frame. I wonder if it was just the metal plate shifting. I can't feel or see any weak spots, even if I put pressure against the braze-on plate at an angle. I suppose I could remove the metal plate and look under it, but then I'd have to remove the front mech and start over. And I'm not sure the metal plate will stick back on. And I'm not sure I'll see a crack even if it is there.
I don't know. Carbon is pretty sturdy. I should probably stop worrying and just ride it.
I don't know. Carbon is pretty sturdy. I should probably stop worrying and just ride it.
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If you did everything according to Shimano SI (service instructions) you should be fine. The amount you have to turn that support screw after it contacts the plate is microscopic...you're barely even contacting the plate, then maybe 1/8th of a turn more. If you were 'tightening' that like any other bolt even remotely close in size you way overdid it. If you just tightened enough to contact the plate and get the cage parallel to the chainring, you're fine.
You can't tighten the support bolt "too hard" unless you bottomed it out and kept turning the allen key. The plate has some adhesive tape on one side of the back so it's possible that it shifted while you were tightening the bolt. If you inspected it thoroughly and don't see any damage I wouldn't worry about it. Just make sure the bolt didn't slip off the plate and is now touching the frame. The seat post bolt on my Cervelo S2 makes a loud cracking noise when you tighten it. It used to give me a mini heart attack when I first got the bike.
[video]https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CC0QtwIwBA&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DgqQ 99s4Ywnw&ei=CEPCVKDaBZOAgwTC6YHwAQ&usg=AFQjCNHz0ydYJuJqqhICCg4QCGKsJQwTqQ&bvm=bv.84349003,d.eXY[/video]
Just kidding.
The instructions in the DM are pretty vague. I followed them carefully, but I think that I "toed in" the front mech way too far, and then was using the support bolt to get everything straight. It was a few turns. I realize the instructions only call for .5mm, which really is microscopic.
Before work this morning, I removed the FD, then removed the metal plate. Cleaned off that spot on the frame. I don't see any damage or feel anything loose. I imagine I could have caused some cracking below the paint or around one of the bolts that attaches the braze on mount to the frame, or I could have even cracked the glue between the braze on and the frame. Or, and this is my hope, it might have been simply a noise.
Anyway, I put everything back together, following the advice from CXwrench and Dunbar. Time will tell. And also a test ride.
You could remove the seat post and check it, your local bike shop may have a scope.
You could try removing the seat post and us a scope to check for damage to the carbon on the inside. Your local bike shop may have a scope or you can by cheaper ones at Harbor Freight. I know they are used by bike shops to check for carbon frame cracks internally and to check that internal cabling isn't crossed. I know I worry about my carbon frame all the time as well.
Just kidding.
The instructions in the DM are pretty vague. I followed them carefully, but I think that I "toed in" the front mech way too far, and then was using the support bolt to get everything straight. It was a few turns. I realize the instructions only call for .5mm, which really is microscopic.
Before work this morning, I removed the FD, then removed the metal plate. Cleaned off that spot on the frame. I don't see any damage or feel anything loose. I imagine I could have caused some cracking below the paint or around one of the bolts that attaches the braze on mount to the frame, or I could have even cracked the glue between the braze on and the frame. Or, and this is my hope, it might have been simply a noise.
Anyway, I put everything back together, following the advice from CXwrench and Dunbar. Time will tell. And also a test ride.[/QUOTE]
You could try removing the seat post and us a scope to check for damage to the carbon on the inside. Your local bike shop may have a scope or you can by cheaper ones at Harbor Freight. I know they are used by bike shops to check for carbon frame cracks internally and to check that internal cabling isn't crossed. I know I worry about my carbon frame all the time as well.
Just kidding.
The instructions in the DM are pretty vague. I followed them carefully, but I think that I "toed in" the front mech way too far, and then was using the support bolt to get everything straight. It was a few turns. I realize the instructions only call for .5mm, which really is microscopic.
Before work this morning, I removed the FD, then removed the metal plate. Cleaned off that spot on the frame. I don't see any damage or feel anything loose. I imagine I could have caused some cracking below the paint or around one of the bolts that attaches the braze on mount to the frame, or I could have even cracked the glue between the braze on and the frame. Or, and this is my hope, it might have been simply a noise.
Anyway, I put everything back together, following the advice from CXwrench and Dunbar. Time will tell. And also a test ride.[/QUOTE]
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