Carbon steerer wear?

Discuss light weight issues concerning road bikes & parts.
xcnick
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Joined: Fri Jan 21, 2011 5:27 pm

by xcnick

Hi all,

Today I removed the forks from my bike (Deda Scuro RS) to clean up the headset etc and noticed on the back side of the steerer a kind of groove where the headset split ring sits and is the same size as the ring (about 5mm tall). It is not a deep or sharp groove but is noticable by eye and when you run your finger over it. I did not have the time to take photos before I had to put it back together. My question is, is this normal? Or been seen before? Of course, I am concerned!

I googled to find something similar and found this

http://www.cyclingnews.com/news/photos/ ... nts/148216

"Cane Creek's new upper cap assembly includes a fully captured split ring that is also supposedly gentler on carbon steerers" interesting?

by Weenie


Geoff
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by Geoff

I have never seen that happen before. Due to the stresses on the steerer, that is quite worrying. Post a pic.

sungod
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by sungod

i had a fork (columbus) where the steerer seemed to have been slightly worn/embossed by the stem clamp

after a long hard look i decided it was the (quite thick) surface coating on the steerer rather than the cf itself that was marked, still concerning though

xcnick
Posts: 120
Joined: Fri Jan 21, 2011 5:27 pm

by xcnick

I stripped it down again and took some pics, the more obvious groove is on the rear facing part of the steerer. I took the forks into my LBS and he wasn't concerned at the mark and wouldn't have a problem riding it himself, even though he knew I was interested in binning it and buying a new frameset from him!

There is no embossed marks from the stem, this is from the split ring in the top headset bearing.

I'm in a bit of a pickle now I think!

Image
Image

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Calnago
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by Calnago

I've seen that before on a Trek I was working on. I think it was around the time that Trek steer tubes got a bit of bad publicity and a few pics were thrown around of the steer tubes sheering off right below the stem. I did a fair bit of research into this because they had a funky expander bolt with a spring which essentially forced you to use a spacer on top of the stem (which I generally do anyway to ensure full stem to steertube contact). I discovered that Trek also recommended at least one 5mm spacer underneath the stem as well as on top. I checked with a local dealer of Trek (very large dealer) where I knew the manager and he said they've never seen a problem. Anyway, I trimmed the steertube and basically cut it flush with the top of the stem. Kept a 1cm spacer between the stem and the headset top cover. No problems since.
I do think I remember reading something about Trek changing the layup a bit going forward. That's not to say that there is a problem with your steer tube or others.

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madcow
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by madcow

That's not the first time we've seen something like that. If it were my bike and I had the money I'd replace the fork. If the fork costs a couple hundred dollars and lasts a few years that's a pretty small investment spread out over time. I've seen failed steerers in the past, and it's never pretty, it almost always ends with an injury and while maybe not a large risk, one that I'm not willing to take.

I can tell you that there are multiple members of this forum who have woken up in the hospital/ambulance, one very seriously, when they had steerer tube failures on a fork. The fork is probably the last place you'd want to have a failure.

xcnick
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Joined: Fri Jan 21, 2011 5:27 pm

by xcnick

Thanks for the reply Calnago. I'm kind of glad someone else has seen it before!

I have been using a 5mm dedacciai headset with a 10mm spacer under the stem and a 10mm spacer above. Since finding the mark on the steerer I have fitted a 15mm Ritchey headset, so doing away with the spacer below the stem. I will monitor the steerer over the next couple of months.

Problem is this is always going to be in the back of my mind as I ride this bike.

Actually, a recent article on Velonews about carbon steerers and Cervelo's designer campaigning for stricter testing prompted me to remove and inspect mine!

xcnick
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Joined: Fri Jan 21, 2011 5:27 pm

by xcnick

Madcow: have you ever found out why this would happen? Thre must be a cause. Could the headset bearing cups be out of align in the frame? The frameset is around 18 months old and covered maybe 8,000 miles.

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madcow
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by madcow

There are several things that can happen to cause this. Loose headset, poor tolerance in headset bearing fit, poor tolerance on frame faces/cups, poor fit with cups/bearings into frame, flexy steerer or even flexy headset. Not everyone will remember M2Racer, but they had a delrin headset which allow the bearing to float a little bit. That floating lead to many cut steerers and a recall of the headset as well the demise of the company. Though it's important to remember that stories like these aren't limited to anyone brand.

One important factor is how overbuilt the steerer is, the more overbuilt the more damage it can take before it becomes an issue. The problem is that you just have to go on intuition as to how much damage the steerer can take, I like to sit on the side of caution.

xcnick
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by xcnick

Thanks again Madcow.

I have ridden some Easton EA90 SL forks for around 6 years on a Specialized S-Works E5 and there is not a single mark on them. What you say makes sense and points to poor quality with my current deda frame. Obviously whatever is going on is going to get worse and a new frameset is going to cost less than new teeth and all that.

It's a real shame and disappointing to have to go replacing this frame, but I am likely to go for a Bianchi Sempre next-good warranty and a LBS for support.

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btompkins0112
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by btompkins0112

LBS support is often worth the price difference, for sure!

xcnick
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by xcnick

Infact look at how the headset sits on the frame it doesn't sit fully square with the headtube. I never thought much of it as the headset was always smooth and tight but is possibly a problem.

Image

xcnick
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Joined: Fri Jan 21, 2011 5:27 pm

by xcnick

btompkins0112 wrote:LBS support is often worth the price difference, for sure!


Actually in this instance the good price is a reason for using the LBS! If you want a frameset he will order in a full bike and sell you the frame at a lower price and sell off the rest of the components! Win Win :thumbup:

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Calnago
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by Calnago

Yeah, Madcows answer is the best one, especially since you said it would now always be in the back of your mind. It would probably be in mine too. What he said about the "toughness of the steertube" makes total sense as well. I am quite used to cutting Colnago steertubes and when I was cutting the steertube with the above issue it was surprising to me how easy it was. To oversimplify things it was like cutting though butter compared to a Colnago steertube.

by Weenie


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kac
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by kac

I'm wondering if routine replacement is prudent (and, if so, at what time interval) or should the fork only be replaced if there is visible damage to the steering tube? Thoughts on this, please.

KAC

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