steerer

[ada@prorider.or]

from cyclingnews.com

Scott Daubert: One thing I forgot to tell you about is that George is running with a different fork; it has a longer axle to crown dimension, and it has a longer rake than the normal Bontrager Race Lite fork.

CN: Is this something new you'll bring into the Trek line?

SD: No, it's actually from Bontrager's Satellite line, almost from their commuter level, but it has dimensions that are appropriate for Roubaix. It's an in-house made fork, made at Trek from OCLV carbon, it's just on a different model bike.

CN: Is it a steel steerer?

SD: No, it's aluminium; it's been blasted then anodized black.




meaby they did not used aged and rolled alu for the fork
so meaby i am just guessing the fork braked due to hardning during the race
if they used aged and rolled alu they would probely not happend
becuase aged alu its stress releived
well i feel very sorry for george but things like this can always happen but it sould not i agree

[Geoff]

cycling news also says that Boonens Time they switched to a steel steerer. I wonder how many of each material are being run in a race like this and how much sh*t George is going to give the guys at Trek. If this had happened to Lance I think there would have been head rolling by now.

[shaq-d]

cycling news also says that Boonens Time they switched to a steel steerer. I wonder how many of each material are being run in a race like this and how much sh*t George is going to give the guys at Trek. If this had happened to Lance I think there would have been head rolling by now.

well, lance is fanatical about his stuff, isn't he? chances are if lance was trying to win PR he'd do what boonen did; ride a bike with a steel steerer, 25mm, etc. in other words, it wouldn't have happened if lance was in charge, cuz lance looks after himself.

sd

[RedCoeurd'Acier]

especially if he was to be a "protected rider at the Tour this year. Depending on what surgery he needs, i would say he'll probably be out for 4-6weeks at the least. So his Tour chances are probably gone.

[nobrakes]

Now I'm beginning to question fork makers who were knocking composite (glued together) forks over their own one piece carbon forks. They seemed to intimate that carbon forks with alloy crowns and steerers were the weakest, those with carbon blades and crowns with alloy steer tubes in the middle, and one-piece all carbon forks the lightest and strongest. I know manufacturer's claims can vary from reality by a great deal, but this claim and comparo was from a company who has a great reputation.

[nobrakes]

...upon rereading the article in Cyclingnews, it seems the reason for the fork change on George's bike was for clearance and geometry considerations, and not a stronger-than-all-carbon reasons. My faith in full carbon forks is restored. Trek doesn't make an all-carbon fork, either. But what about Boonen's steel steerer? Did they also use this fork for clearance and geometry reasons? Be interesting to find out.

[asgelle]

meaby they did not used aged and rolled alu for the fork
so meaby i am just guessing the fork braked due to hardning during the race
if they used aged and rolled alu they would probely not happend
becuase aged alu its stress releived

Maybe they used aluminum foil rolled into a tube for the steerer. I don't know and I'm just guessing that the fork broke because, well, aluminum foil really doesn't work for steerer tubes. If they used better material it probably wouldn't have happened; unless it did.

There are limitless possible causes for the failure and to pull one out of thin air without any evidence to back it up as the likely reason is meaningless and irresponsible. Now if you some reason to believe the aluminum was not stress relieved and that stress relieving would have made the difference between survival and failure, share that information. Otherwise, you are, once again, slandering a product with absolutely no evidence.

[ada@prorider.or]

Maybe they used aluminum foil rolled into a tube for the steerer. I don't know and I'm just guessing that the fork broke because, well, aluminum foil really doesn't work for steerer tubes. If they used better material it probably wouldn't have happened; unless it did.

There are limitless possible causes for the failure and to pull one out of thin air without any evidence to back it up as the likely reason is meaningless and irresponsible. Now if you some reason to believe the aluminum was not stress relieved and that stress relieving would have made the difference between survival and failure, share that information. Otherwise, you are, once again, slandering a product with absolutely no evidence.

mmm i really gone have problems explain things
first of all rolled does not mean the tube must be rolled
its a way of produce aluminum
and aged also
i advise you to search the web first before lot of tech stuff come to you
first look at the treatment T7351 of alu if you understand this then we can go one step by step otherwise you loose track
agreed?

http://normen.nen.nl/nen/?ics=49.025.20

[Grant McLean]

It's easy to read too much into 1 fork being broken. IF the fork in question
truely was a "stock" fork from a trek Pilot like the interview suggested,
there are likely 1,000's of them in use. If they haven't had a problem or
recall in the market place conditions, there isn't likely too much to be made
of 1 broken fork. It could very well be that the fork George rode was a
prototype, since the bikes they rode for P-R are not sold to customers.

George did have a crash earlier in the race, that could have been the ultimate
cause of the failure.

It's not good to see riders getting hurt from part failures, and it's definitely
not good marketing, but drawing a connection with stuff you buy in the LBS?
I wouldn't place much stock in that. There just isn't enough of a sample size
to come to any useful conclusion, especially since we don't know all the facts.
But don't let that slow down your opinions!

-g

[ada@prorider.or]

well paris roubaix is not any race
they brake things in the race all the time
so i am not suprised and pro racing is like formula one
you try things out in exteme condition that hard to reproduce in lab
so from this point its not so strange
i see frame brake fork handle bars and so one braking all the time with pro races so that becomes normal


only the way things brake must give you some thoughts
my products probely also will break at a time
only i hope never in a decent or something like that
thats the design to build in safe guards

in this light if you examine the brake from video
you get some tought what meaby caused the brake


and again paris roubaix is a extremly hard race


luckly if have test rider living at the course of paris roubaix to test exteme conditions
so from this we learning and understand things

[Chief]

You learn by failing. If you never fail, you will never know your limits. The same goes for engineering structures; eg, bike components; if they don't fail, you never know their limits.

[Lincoln]

You learn by failing. If you never fail, you will never know your limits. The same goes for engineering structures; eg, bike components; if they don't fail, you never know their limits.

That's what practice and testing are for. Unless you have no chance without it, a race is not the place for testing (especially for the team leader), atmo.

[Dr. Doofus]

was the same fork on his bike last year?

how many other bikes used the same fork?

[Erik.Lazdins]

was the same fork on his bike last year?

how many other bikes used the same fork?

I know that Time had a steel steerer and a 18.5 lb specially built bike
I think Mapei ran all steel forks with the C-40's in the past.
I know that Magnus at 198 didn't break his bike (all Ti?) when he won.

I think Trek has had the 1 1/8 headtube with AL steerer with carbon fork since at least 2000. That's a lot of bikes, plus Scott allowed cycling news to do the story so that speaks to some confidence in the bikes ability to perform its designed mission.

George crashed hard enough earlier to where he said he was concerned about his ability to hold on for the rest of the race. Did something happen there?


One last observation off the subject...
They call George big, they call Jan big, they call Robbie McEwen "little"

George is 165, Jan is 160, and Robbie is 148. Not a big difference between little and big in cycling, is it?

At the end of the day - it's a bummer that a mechanical decides the final animators in a great classic.

Keep the mud, keep the rain, keep the Arenberg, keep the flag waving/frite eating/Duvel drinking fans, lose the mechanicals and tell the goods train to take the day off next April.

[BumbleBeeDave]

. . . a wild-@ss guess here and say that I bet the earlier crash had something to do with this failure because if you look at the close-up shot of his bike on VeloNews, you can see that the steerer tube broke right at the lower edge of the stem. To me, that indicates his bars probably took a big hit on the earlier crash that compromised the steerer tube at that point because that would seem to be the stress point if you give the bars a big hit. The tube probably cracked then and when when he had ridden a while and it took some more stress it just gave way.

I hate to disagree with Cees--he's obviously much more qualified engineering-wise than I am (like THAT would take much! :rolleyes: )--but if I were racing in this event or managing a team, I would deliberately NOT use prototype stuff. I'd sacrifice a few ounces extra of weight for assurance that the stuff will WORK when it has to. Disco didn't do that and now look how embarrassed they and their sponsor are AND they may have lost their best hope for the Tour. Dumb, dumb, dumb . . .

BBD

[Ginger]

This may just be coincidental, but I know of another Bontrager fork aluminum steerer failing. JRA.

Not saying it's the same issue...as this one was half way down the head tube...but it is Strange...

[Erik.Lazdins]

Thanks for posting the pic it shows the break area

Is the picture saying the steerer broke but the bottle cages held strong?


"It puts the cream on the chamois"

[BumbleBeeDave]

. . . I just came upon from CyclingNews for tomorrow, April 11 . . .

BBD
____________________________

Trek to examine Hincapie's fork

Discovery team bike sponsor Trek is having the fork from George Hincapie's bike returned to its US headquarters for a "thorough evaluation."

Hincapie sustained a broken bone in his shoulder when the steerer tube of his bike broke 45km from the finish, causing him to crash. Trek and Discovery say they suspect the crash was caused by damage sustained in an earlier incident. "George was in a crash earlier in the day, but due to race conditions and his comments that everything seemed fine, we did not change to his back up bike," said Discovery's directeur sportif, Johan Bruyneel, in a statement.

Shortly before the second crash, Hincapie told team directors that he felt looseness in his steering and thought his headset may have come loose as a result of the earlier crash. The team was figuring out when and how to swap to his spare bike when Hincapie entered another cobbled section and crashed.

"I believe that the first crash set the stage for the big crash", said Bruyneel. "Section after section the vibrations just kept coming until the damaged steerer gave loose."

"The cobbles do not discriminate," said Julien De Vriese, the team's head mechanic.

[Brian Smith]

Hypothetical question:

If Discovery were normally on F3 forks, would they need "special" longer forks (from lower end bikes) with extra clearance for those tires?

Here's an F3 with a tire measuring around 27mm wide with about 4mm clearance on each side.

Who knows, poor GH.

[andy mac]

bits breaking, mud, trains, wrecks, DQ's - it doesn't take away, it's adds to the whole thing.

sport - so predictably beautifully unpredictable.

:beer:

bring on the L-B-L!

[dbrk]

Hypothetical question:
If Discovery were normally on F3 forks, would they need "special" longer forks (from lower end bikes) with extra clearance for those tires?
Here's an F3 with a tire measuring around 27mm wide with about 4mm clearance on each side.


Brian,
WHICH 27c? For not all tires are what they say they are...as we know well!

The clearance you show here gives me hope. Cervelo too is touting that it's R3 has clearances...but then the design has chainstays under 40cm and a 68mm bb drop! Crit bikes. Good for some, not for me. Oh, we were on forks...I'm very much looking forward to riding the F3 on my new Legend. Soon!

Thanks for the excellent picture.

dbrk

[Geoff]

I think in a race like PR that the AL is not hte best fo rcertain parts. AL and carbon dont generally bend when damaged they fail completely were as steel will bend and still be ridable until the change could be made.

I have a Bontrager Race lite steel MTB fork that I have ridden for about 14 years that has sustained numerous crashes including one headon with a car door at 30 mph. The fork is still solid and true and as the name says is very lite and it is a MTB fork.

My question is that some teams seem to be less intune with the demands of the race and the necessisty of part durability and more concerned with wieght savings or using there parts?

I wish there was a way to figure part failure in a race like this over time.

[e-RICHIE]

I wish there was a way to figure part failure in a race like this over time.

there is.
don't repeat the mistake.

[Brian Smith]

Brian,
WHICH 27c? For not all tires are what they say they are...as we know well!

The clearance you show here gives me hope. Cervelo too is touting that it's R3 has clearances...but then the design has chainstays under 40cm and a 68mm bb drop! Crit bikes. Good for some, not for me. Oh, we were on forks...I'm very much looking forward to riding the F3 on my new Legend. Soon!

Thanks for the excellent picture.

dbrk

Actually, I've misspoken.
This is the same photo I sent you a good while back.
It measures, IIRC, a little under 27mm, and is a pretty old Specialized tire marked 26(c). I don't recall exactly which and exactly the dimension, since it was about 6-8 months ago that I took the photo. I said 27mm because I meant 27mm, not a "claimed 27c." Others here, IIRC, have claimed Rivendell 27mm tires NOT to be an acceptable fit. Try a search, I think the info is here somewhere.
Here's the punchline: I wish the s-bend chainstays had as much clearance as the F3. I think the F3 has enough for most peoples' ideas of rennrads, road racing bikes, you know what I mean - not by any strech randonneurs nor touring bikes nor all-rounders, but bikes that you've maybe before referred to as "go fast" bikes.

Back on topic, I think the notion that the steerer was previously "blasted" and anodized black is pretty interesting. Of minor interest to me is why they did it; did they want it to "look" like a carbon steerer? to differentiate it from a "Pilot" fork? to give it some differing physical property? Of major interest to me is the idea of blasting and anodizing the steerer of an already constructed fork. What makes that necessary, desirable, or even OK? Are there forks made with aluminum steerers that are not ALREADY anodized, albeit usually "clear" and not "black?" Since anodizing does not add a layer of material in the manner that plating or painting does, is it "cool/ok" to "blast" a layer of material off the fork, re-anodize it, then clamp it in a stem made (ostensibly) for a steerer of the original dimension? What happens near the crown where the steerer enters the carbon and you have still a layer of original anodizing under the paint/carbon and a new smaller diameter but maybe thicker anodized layer adjoining it? At any rate it seems like a lot of work for aims not immediately apparent.

Here's my best hope:
In order to make the steerer more agreeable to the atypical abuse of a team fork that is going to be installed, removed, installed, removed, possibly not protectively stored, possibly dropped here and there in the process and not worked on under strictly the nicest shop environments, the new anodizing was made "thicker than stock" to better protect against scratches and abrasions incurred not in use but in installation removal and storage. Then lets say that the previous crash would have damaged even a normal "Pilot" fork or most others in use that day, and the failure was in no way related to the processes by which the fork was made nor the design.

"cobbles don't discriminate" has a great ring to it, but the fact is that one fork failed and others didn't, and maybe force levels were unanticipated, but that doesn't make failures unavoidable.

[manet]

"cobbles don't discriminate" has a great ring to it

"cobbled together _ cobbled apart"

[pdxmech13]

After years of fixing bikes that have beened "garaged"
I was trying to think of one example of a steerer tube breaking.
The funny thing is I can't. Every other part on a bike though I have.
Even say someones Audi that had irreparable damage to the roof.
Poor guy didn't claim it on his insurance and suck up the cost of a new A8

[Vancouverdave]

I didn't realize the break was at the bottom of the stem clamp. This will keep me examining the inside and bottom edge of customers' stems VERY carefully, and Trek should too! Aluminum is prone to "notch failure," which means simply that a scratch becomes a crack. A whole lot of handlebar stems seem to be poorly finished in both the steerer clamp and handlebar clamp, with Italian-made stems noticeably worse than Taiwanese stems. Ritchey seems to do the best job of this.

[Marcusaurelius]

from cyclingnews.com

Scott Daubert: One thing I forgot to tell you about is that George is running with a different fork; it has a longer axle to crown dimension, and it has a longer rake than the normal Bontrager Race Lite fork.

CN: Is this something new you'll bring into the Trek line?

SD: No, it's actually from Bontrager's Satellite line, almost from their commuter level, but it has dimensions that are appropriate for Roubaix. It's an in-house made fork, made at Trek from OCLV carbon, it's just on a different model bike.

CN: Is it a steel steerer?

SD: No, it's aluminium; it's been blasted then anodized black.




meaby they did not used aged and rolled alu for the fork
so meaby i am just guessing the fork braked due to hardning during the race
if they used aged and rolled alu they would probely not happend
becuase aged alu its stress releived
well i feel very sorry for george but things like this can always happen but it sould not i agree


I am not sure if a commuter (bontrager satellite) fork is any less durable than Bontragers (Trek) much more expensive forks. I know they said the frame is a prototype but I am not sure the fork isn't a stock satellite? Wether it was the crash or just a fork defect I think I would have not used a commuter fork in a big race like the Paris Roubaix. If it was a prototype fork then I think the Paris Roubaix isn't the best place to test unproven products. I will be curious to see what Trek says after they get the fork back and can examine it.