[Balderick]

I have a bike - I will not mention the brand, but it is American designed and probably constructed in Asia somewhere. High modulus carbon is used in the frame and carbon steerer fork. I like the frame and the fork.

I had a problem with the carbon steerer, where there seemed that the inside front face of the stem had worn away the outer surface of the steerer. The fork/frame importer looked at, and said it was safe but to keep monitoring monthly. I had the bike shop check it at least monthly, for I am a large (100+ kg) and strong rider, and one of the courses I race at has rough patches that are probably close to pave'. The LBS reported no problem, and swapped out the stem so the contact spots were different.

I raced last Sunday on the aforementioned course. The front end of the bike felt fine riding to racing, and during racing, and I did not hit anything unusual during the race. However, on the ride home from racing I thought the front end felt "soft" - I then twisted the bars forward and they moved. Showed it to a friend, who owns another LBS, and he said ride it carefully back to his shop. His mechanic stripped it down and the carbon steerer looked like it had delaminated around where the stem had been fitted.

The LBS that sold the bike has a very good mechanic, and i have no doubt he did all that was required - he is a torque wrench kind of guy. The forks is being sent back to the importer, and I expect it will be covered under warranty. I am still mobile, as I have been lent a Chromo-moly fork which is much better than I thought it would be.

That background given, my question is whether others have experienced this kind of delamination, or failure, of carbin steerer. I get kind of nervous with carbon steerers. Do I ask for a cheaper fork with an Al steerer, but then I think that the binding between the Al steerer and fork crown becomes the weak link?

 

[justsomeotherdude]

I have to ask....did they grease the carbon steerer at the stem? The only things I have seen cause a delam is excessive heat(heat gun), grease and a small crack that spread.

 

[pmseattle]

Last year I witnessed a spectacular carbon fiber steerer failure which I believe may have been caused by a too-heavy rider on an OCLV. The steerer abruptly snapped apart just above the fork crown, smashing the rider face-first into the pavement. He was seriously injured and had to be hauled away by the EMTs. I took photos . . .

 

[Applesauce]

Surprised this hasn't come up yet... Hincapie demonstrated for the world "the safety of an aluminum steerer" (or whatever tag-line Trek used to attach to it). Hincapie's fork did not break at the crown's bonded junction; it snapped at or above the top race. I won't conflate correlation and causation, but Trek has since started offering all-carbon forks, and plenty of very big guys ride Treks (and similar brands). Part of cycling, I think, is being comfortable with the fact that anything you're riding could, at any time, fail, catastrophically or otherwise. Some things are less likely to fail than others, though, and I think that's what you're asking... But I can't offer much advice. I weigh 150 lbs and ride a steel frame and fork. (But it, too, could fail at any time.) Take Magnus Backstedt, for instance: why wasn't he just breaking stuff left, right, and center? Smart choices, partly, but surely partly just luck - and good mechanics - too. (Speaking of mechanics, I won't blame yours, but I will say you shouldn't exonerate him completely.)

If I were you, I would not chalk it up to materials. First, I would call it a fluke. (Well, first I would be thankful it didn't leave you hurt, badly or otherwise.) Second, I would see what the manufacturer returns to you under warranty. Does it look exactly the same? If so, that could indicate a) your first one was a fluke and you couldn't have seen (or foreseen) the cause of the failure or b) your second one will fail just like the first, which would be a surprising and stupid - though not unprecedented - chance for the manufacturer to take. If not, they're tacitly acknowledging the problem and hoping nobody dies; but in any case, they're replacing your fork with one that they have deemed less likely to get them sued to nudity. Third, taking all that into account, I would considering going with a fork from a more reputable (though that's hard to say, given that you're justifiably not broadcasting the manufacturer) maker; I've never seen a Reynolds fail (without being crashed, of course), and I've seen them under bigger guys than you. Wound Up and Alpha-Q also make some very, very sturdy models; I have had the steerer (also at the stem, like yours) and bonded aluminum dropout faces delaminate on a Ritchey WCS fork (don't ask how I noticed both at once).

All that aside, I think the neutrality with which you're approaching the issue is great, and certainly refreshing on this forum...

 

[Balderick]

I have to ask....did they grease the carbon steerer at the stem? The only things I have seen cause a delam is excessive heat(heat gun), grease and a small crack that spread.

I have seen no evidence that grease was applied at all, and I'd be surprised. If the guy who built the bike used anything he would have used that Ritchey carbon grippy stuff.

 

[Kerry Irons]

Not likely grease

I have to ask....did they grease the carbon steerer at the stem? The only things I have seen cause a delam is excessive heat(heat gun), grease and a small crack that spread.

There are all kinds of CF parts that are continuously exposed to grease (derailleurs, brake levers) and they suffer no ill effects. While the "no grease" mantra is repeated constantly on the Internet, the only problem with grease is if it cause your stem, bars, or seat post to slip. Not an issue for damaging parts.

 

[tom_h]

...
I had a problem with the carbon steerer, where there seemed that the inside front face of the stem had worn away the outer surface of the steerer. ..

Curious , is the inside of your stem smooth, deburred, and free of sharp edges or ridges? I can imagine that such ridges might act like a sharp knife on the steerer tube, over time, scraping away outer layers of the composite.

FWIW, Specialized posts the following "caution" on their framset/fork assembly. I think it's a bit overkill, and may be self-serving ... since AFAIK Specialized is the only stem I've see with a continuous coverage shim surrounding the carbon steerer :

... Specialized recommends against the use of stems with large bore holes
in contact with the steerer tube. Large bore holes reduce the surface
area and concentrate the load onto the carbon steerer tube....

... The continuous or near-continuous surface area of Specialized stems provides a very high amount of surface area contact with the steerer tube, which helps to evenly distribute loads....
​

​

 

[Kuma601]

IDK if we'll see an ideal stem and fork interface when lightweight is a factor. Specialized tech bulletin does raise some interesting thoughts into stem design. I like what Easton has integrated into their '09 forks with ITT. http://www.eastonbike.com/PRODUCTS/FORKS/fork__top.html

Maybe a re-enforcing sleeve like what Giant has in their Alliance series frames for higher stress and or weight categories. Scary to think about any failure regardless of materials.

 

[PlatyPius]

IDK if we'll see an ideal stem and fork interface when lightweight is a factor. Specialized tech bulletin does raise some interesting thoughts into stem design. I like what Easton has integrated into their '09 forks with ITT. http://www.eastonbike.com/PRODUCTS/FORKS/fork__top.html

Maybe a re-enforcing sleeve like what Giant has in their Alliance series frames for higher stress and or weight categories. Scary to think about any failure regardless of materials.

Being a lard-arse, I decided, upon seeing the new Easton forks that the rep was pimping, that I would be riding Easton forks from now on. They still weigh next to nothing, but they look beefy. I've always been somewhat afraid of a steerer tube failure; especially after seeing the Wolf SL forks that we replaced last year.

And, I gotta say..... the glue-in threaded insert things that a lot of forks use are about the stupidest, cheesiest things I've ever seen. This system by Easton makes much more sense.

 

[Balderick]

Curious , is the inside of your stem smooth, deburred, and free of sharp edges or ridges? I can imagine that such ridges might act like a sharp knife on the steerer tube, over time, scraping away outer layers of the composite.

The first stem did have a sharp edge, but would not call it burred. The hypothesis was that the wearing on the front side of the sterrer had been caused by the harp edges on the "front" side of the stem. So tThe LBS owner and I went through a whole box of new stems - most very much high end - and all had different degrees of burring and sharpness. In the end the Stem selected - a 3T stem - had more material on that critical interface. No, the LBS did not sell Specialized stems.

While I think the hypothesis was correct, the delamination on the rear and side of the stem suggests to me that the underlying problem is that the steerer was failing along the main point where it was stressed, being the interface with the stem. It failed first on the front because there was greater force per area on that front part of the steerer, as the stem was made lighter.

I can see some real sense in the Specialized system. To me it makes a lot of sense to have a larger contact area of a stem binding to a carbon steerer.

Might not make a whole lot of difference when the roads are smooth or the rider weighs less than 80 kg. However, for a larger rider like me I will take a reliable part over a lightweight one. Last thing I want to happen is for the stem to fail. I had a lightweight alloy bar snap in the early '80s, at 60 kph, and I doubt I would "bounce" as well now as I did then.

Another potential issue was the steerer plug used. I will be insisting on the use of a better/longer/thicker plug.

I am not angling to scam a new fork out of the importer. If it is a warranty issue and they give me a new fork then that is great. However, ultimately I am more than happy to buy a compatible safe sturdy fork.

As an aside, the CrMO fork my LBS owning mate (not the shop I bought the subject bike from, although both are mates) has lent to me is a real trip back to the days when I had a 6 pack stomach, was too young to drive a car and steel was not just real, it was all mere mortals could afford. I raced a crit yesterday and the fork, bolted (securely) to a still HM carbon frame felt a bit "out of sync" on the tighter corners, almost like it was less dampened. It was a tight course with three 180 degree turnarounds, anda host of faster 90 degree turns. It was quite nice throught he faster corners, but felt :Wrong" when coming hard under brakes in to a 180 turn.

Overall this fork is nice (but oh so heavy) but has a less dialed in feel to the forks that they are replacing. But I think this fork - I think it is off a track bike - is unlikely to break, or if it does it will bend first.

 

[tom_h]

3t

I've read other favorable comments regarding the good finish on the inside of the 3T stems.

 

[kiwisimon]

Hope the rider got better soon. plus one Applesauce.

 

[-dustin]

Last year I witnessed a spectacular carbon fiber steerer failure which I believe may have been caused by a too-heavy rider on an OCLV. The steerer abruptly snapped apart just above the fork crown, smashing the rider face-first into the pavement. He was seriously injured and had to be hauled away by the EMTs. I took photos . . .

How on earth does that happen? What did Trek have to say about that?

 

[PlatyPius]

How on earth does that happen?

Magic, apparently. A whole bunch of people here on RBR will expound upon the virtues of carbon and how it never fails and will last forever.

Always remember kids, carbon does NOT explode!

 

[nightfend]

I've noticed that Colnago has a 90kg rider limit for their frames and forks and they overbuild their carbon steerer tubes. So I think weighing over 200+ doesn't help the situation.

That said, you just never know... as was mentioned, the famous Hincapie crash was caused by an aluminum steerer tube failing on his fork.

 

[Applesauce]

...It was quite nice throught he faster corners, but felt :Wrong" when coming hard under brakes in to a 180 turn.

Overall this fork is nice (but oh so heavy) but has a less dialed in feel to the forks that they are replacing. But I think this fork - I think it is off a track bike - is unlikely to break, or if it does it will bend first.

Most likely it's not a question of "damping" that could be traced to materials, etc.; most likely, the geometry of the fork is not compatible with that of the frame, i.e., the latter was not designed for use with the former. This is something you should consider (i.e., measure) carefully if you go for an aftermarket fork.

 

[il sogno]

Do you have a Giant? They had a fork recall recently.

http://forums.roadbikereview.com/showthread.php?t=159600&highlight=fork+recall

 

[Sherpa23]

I have a Reynolds Ouzo track fork with a cracked steerer. I used it for a whole season and it was fine, and then I broke it on an indoor track. I have been switching to Edge forks, anyway. Still, it's disappointing as I really like Reynolds products.

 

[Balderick]

I've noticed that Colnago has a 90kg rider limit for their frames and forks and they overbuild their carbon steerer tubes. So I think weighing over 200+ doesn't help the situation..

I do weigh over 90 kg - but thankfully not over 200kg! Heaviest I weighed was 123kg, and lightest in the "post children" phase of life was 95 kg.

I am always mindful that manufacturers will design a bike to suit riders under 80 or 90 kg, and might be driven by market forces to put bikes out there that are lighter than my needs might require. Hence the bike in questions was selected because it was designed to be for larger stronger riders - that is, for sprinters rather than pure climbers.

Do you have a Giant? They had a fork recall recently.

I do, an 03 TCR composite with an Al steerer. It has done 40,000 k of riding, including the time when I was 123 kg, and never missed a beat. It is, however, a bit of noodle c/f the current bike, which is a very nice stiff frame. I rode the Giant last week and I swear that with a Ultegra rear wheel (I( usually ride a 32 spoke CXP33) it felt like an old Proflex MTB!

A number of my friends have the Giant bikes subject of the fork recall. None of their returned forks had any cracks or other external signs of failure. Good to see a manufacturer taking a conservative, and no doubt expensive, approach to this. But then, they sell a lot of bikes in litigation prone countries like the USA and Australia, so caution is probably also sound business.

I read with some concernt hat some people have ridden on forks they knew to have a crack. In my (law) firm we have acted for people that were severly injured when their forks (in each case on a MTB) failed, and in each case they were riding slowly and were riding on a piece of junk purchased from a supermarket. My respectful point is not to avoid riding poorly designed and manufatured bikes - most on this forum know that - but that the consequences of a fork failure can be serious at low speed, and horrific at the higher speeds we all tend to ride at on road bike. Not intended to flame those who have done it - we are all adults able to make our own decisions - but just urging people to be careful.

 

[tom_h]

As an aside, Specialized -- and possibly other Mfrs too -- uses carbon steerers that oversized at the bottom of the steerer (IIRC, 1.50") and tapering to the standard 1.125" at the top.

While this makes for a proprietary fork design, it increases strength against the type of failure depicted in post # 3 -- for a constant wall thickness, large diameter tubes are stronger.

Offhand, I don't know when Spec'y started with the oversized steerers -- my 2009 Tarmac has one.