Carbon steerer question
#1
Newbie
Thread Starter
Carbon steerer question
Hello all,
Looking for some advice.
I noticed at the beginning of last summer that there was a tiny 'line' on my carbon steerer tube just above the lower stem bolt. I actually just thought it was cosmetic marking, so have been riding on it ever since. Over the winter, the bike has been 'parked' while I have been on the winter machine, so I decided to drop the fork out just to be sure.
When I removed the stem, it was immediately apparent that it was not what I thought. There was a crack running down about 1cm from the mark I could see (covered by the spacers). It looks as though the lower stem clamp bolt has, at some point, been overtightened and 'compressed' the steerer tube.
To assess just how bad the damage was, I removed the expander bung and checked the inside. I could indeed feel a 'bump' where the line was on the inside of the tube.
Although I think I (sadly) already know the answer, could somebody answer for me: is the fork 'toast'? The mark was originally noted in June/July 2023 and I was riding it until October, and it never got any worse (from what I could see). However, now I have seen it 'properly' I am uneasy about riding it. The bung is actually very long (by modern standards) and comes right down all the way past the stem inside the tube.
Is it time for a new fork?
I wanted to attach images, but as I have only just joined the forum I can't. Bit of a silly rule?
Thanks in advance!
Last edited by zactaylor; 03-17-24 at 05:46 AM. Reason: Adding images.
#2
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I sure would not ride a carbon steerer if there was an obvious crack. It will fail at the worst possible time, with disastrous results.
I have seen some ways to sleeve them using a carefully sized plastic insert and epoxy but not as a repair technique
If you do get a new fork, spend the 20 bucks extra and get the expansion nut that supports the thin wall carbon steerer better than a star nut
/markp
I have seen some ways to sleeve them using a carefully sized plastic insert and epoxy but not as a repair technique
If you do get a new fork, spend the 20 bucks extra and get the expansion nut that supports the thin wall carbon steerer better than a star nut
/markp
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Hello all,
When I removed the stem, it was immediately apparent that it was not what I thought. There was a crack running down about 1cm from the mark I could see (covered by the spacers). It looks as though the lower stem clamp bolt has, at some point, been overtightened and 'compressed' the steerer tube.
To assess just how bad the damage was, I removed the expander bung and checked the inside. I could indeed feel a 'bump' where the line was on the inside of the tube.
Thanks in advance!
When I removed the stem, it was immediately apparent that it was not what I thought. There was a crack running down about 1cm from the mark I could see (covered by the spacers). It looks as though the lower stem clamp bolt has, at some point, been overtightened and 'compressed' the steerer tube.
To assess just how bad the damage was, I removed the expander bung and checked the inside. I could indeed feel a 'bump' where the line was on the inside of the tube.
Thanks in advance!
Or is it a star nut/clamp like this:
If it's like this last image, and if you are on a new bike still under warranty, you might want to speak further with your LBS on this. An incorrect clamp may have been used.
#6
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I can’t see any reputable carbon shop repairing a steerer/fork !
What brand/model/year is the bike?
Barry
What brand/model/year is the bike?
Barry
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#8
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I sure would not ride a carbon steerer if there was an obvious crack. It will fail at the worst possible time, with disastrous results.
I have seen some ways to sleeve them using a carefully sized plastic insert and epoxy but not as a repair technique
If you do get a new fork, spend the 20 bucks extra and get the expansion nut that supports the thin wall carbon steerer better than a star nut
I have seen some ways to sleeve them using a carefully sized plastic insert and epoxy but not as a repair technique
If you do get a new fork, spend the 20 bucks extra and get the expansion nut that supports the thin wall carbon steerer better than a star nut
Last edited by Camilo; 03-13-24 at 03:21 PM.
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#9
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Likely. Take it to a bike shop, where it can be assessed in person.
Spam mitigation rule. You can upload pictures to an "Album" associated with your user account, and other people can link to them from there.
I wanted to attach images, but as I have only just joined the forum I can't. Bit of a silly rule?!
#10
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When you can post a photo that will be the most helpful. Without one no-one can say anything with any accuracy. Sometimes there are layup seams that get confused with cracks or damage so there is that possibility but I would suggest taking it to at least 3 different shops to get an in-the-flesh check which should be the most accurate way to do it.
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Curious if your fork has a steerer tube with something similar to the following:
Or is it a star nut/clamp like this:
If it's like this last image, and if you are on a new bike still under warranty, you might want to speak further with your LBS on this. An incorrect clamp may have been used.
Or is it a star nut/clamp like this:
If it's like this last image, and if you are on a new bike still under warranty, you might want to speak further with your LBS on this. An incorrect clamp may have been used.
#12
Newbie
Thread Starter
Hello everybody
Thank you for all your replies.
I sent the photos to Carbon Bike Repair UK who are a highly-regarded repair shop in Leatherhead. They confirmed it was a clamp fracture.
I am going to contact the manufacturer for a new fork.
I will upload the photos (as I can now) so if anybody would like to add anything feel free!
Thank you for all your replies.
I sent the photos to Carbon Bike Repair UK who are a highly-regarded repair shop in Leatherhead. They confirmed it was a clamp fracture.
I am going to contact the manufacturer for a new fork.
I will upload the photos (as I can now) so if anybody would like to add anything feel free!
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