Trek steer tube failures

[BroDeal]

Velonews article. The comments raise some interesting questions about the accuracy of torque wrenches and the margin of safety of carbon parts.

http://velonews.competitor.com/2010...rned-about-broken-carbon-steerer-tubes_121389

 

[brianf7]

Velonews article. The comments raise some interesting questions about the accuracy of torque wrenches and the margin of safety of carbon parts.

http://velonews.competitor.com/2010...rned-about-broken-carbon-steerer-tubes_121389

Looks like instalation issues to me


nasty I had a stem snap off just as I was about to decend a big hill . not nice feeling but I was able to find some big furns at the side of the road that stoped me quickly and soft landing

that stem always creeked but not now.

 

[Ripper]

Velonews article. The comments raise some interesting questions about the accuracy of torque wrenches and the margin of safety of carbon parts.

http://velonews.competitor.com/2010...rned-about-broken-carbon-steerer-tubes_121389

I read that piece and it does not increase my confidence in Trek. It seems like it is a rash of their bikes/steer tubes, so they can point to anything they want, but it is still just the Madone. I think you make a good point about the margin of safety on some carbon parts. I have a torque wrench and carbon paste, but it sounds like some of these incidents are just too risky, and I cannot really check the calibration of my wrench every month

 

[BroDeal]

I think you make a good point about the margin of safety on some carbon parts. I have a torque wrench and carbon paste, but it sounds like some of these incidents are just too risky, and I cannot really check the calibration of my wrench every month

I thought that was the most interesting thing about the comments. If a part has a low margin of safety that depends on a number of factors being exactly right then there will inevitably be installation issues, especially when the hurried mechanic putting bikes together is a high school or college kid who just does not give a damn. This could be complicated by torque wrenches giving the same values for different clamping forces because of differences in bolt thread lubrication.

 

[Ripper]

I thought that was the most interesting thing about the comments. If a part has a low margin of safety that depends on a number of factors being exactly right then there will inevitably be installation issues, especially when the hurried mechanic putting bikes together is a high school or college kid who just does not give a damn. This could be complicated by torque wrenches giving the same values for different clamping forces because of differences in bolt thread lubrication.

Yup, when this level of complexity can cause catastrophic failure, then there is a pretty big problem. Bottom line, Trek needs to chenge their design (which it looks like they have done).

 

[richwagmn]

Velonews article. The comments raise some interesting questions about the accuracy of torque wrenches and the margin of safety of carbon parts.

http://velonews.competitor.com/2010...rned-about-broken-carbon-steerer-tubes_121389

Also seems the weight savings thing get's a bit out of control. Not sure the weight difference between a carbon steerer and an aluminum one, but it can't be that great.

I'd take the safety of an alu steerer over the weight savings of a carbon one any day.

 

[RDV4ROUBAIX]

I thought that was the most interesting thing about the comments. If a part has a low margin of safety that depends on a number of factors being exactly right then there will inevitably be installation issues, especially when the hurried mechanic putting bikes together is a high school or college kid who just does not give a damn. This could be complicated by torque wrenches giving the same values for different clamping forces because of differences in bolt thread lubrication.

And that's the biggest problem with these big brand boutique shops, they usually let anybody work on the higher end gear, so it causes problems such as this and other mechanical gremlins that could have been avoided. Shops I've worked at turn into the bike shop's bike shop, so when springtime comes almost half of the repairs originated from these boutiques. Let those rookie mechanics cut their teeth on some hybrids, then take a seminar on carbon bike building, which I'm sure Trek offers. They have a seminar on everything, probably even how to wipe your ***.

 

[biker jk]

Also seems the weight savings thing get's a bit out of control. Not sure the weight difference between a carbon steerer and an aluminum one, but it can't be that great.

I'd take the safety of an alu steerer over the weight savings of a carbon one any day.

Perhaps not considering the issue of bonding the alu steerer to the carbon fibre. A one piece carbon fibre fork might be stronger. Perhaps the issue is with paper thin carbon fork steerers.

 

[Oldskoolkool]

Sound like the usual big business trying to pass the buck and blame a third party. A critical part such as a steerer should have a safety margin built in to allow for the differences in stems. They've more than likely designed it too thin in the obsessive race for low weight.
When you look at one of the pics it also seems like the expanded bung doesn't extend very far down the steerer tube so there's no additional support inside. Perhaps if Trek looked into where they could improve their products rather than blame other people then we wouldn't have these sorts of problems.
Mind you companies such Trek don't design products with longevity in mind,they want us to buy new frames every couple of years.

 

[Radders]

I've got two 6 series Madones, a 2009 model and a 2010 model and I've owned a couple of the older style Madones. I was a little concerned to read this article as I've always been a little wary of super lightweight products. I did buy a torque wrench allen key when I switched from the aluminium steerers of the old models to the new carbon steerers to ensure I wasnt overdoing things and I've always run a 5mm spacer on top of the stem. To date, no issues, despite a couple of off road excursions and hitting a few hefty pot holes hard enough to shift the handle bars forward. I did speak to my dealer about this, but he hasnt raised any concerns.

I've always found Trek to have excellent customer service and warranty replacement, so I cant see them doing this to make you buy new bikes every year. I have had one Trek frame warrantied 3 times due to paint issues.

Looking at the photos in the article, there did seem to be a lot of stack between the headtube and the stem, surely the rider would be better off with the performance fit, rather than the pro fit, which has a 2cm longer head tube.

Does this highlight another issue of riders trying to ride bikes that dont fit them properly?

Still rather concerning though, I'll be checking my steerer tubes tonight!

 

[Oldskoolkool]

I do agree with Radders on the issue of frame fit,.....too many people seem to buy a frame too small for them because I get the impression they think its cool or something to have masses of seatpost showing,but they then have 30-40mm of spacers under the stem,which cannot be good for a carbon steerer as it leaves alot of relatively unsupported tube above the headset bearings.

 

[BroDeal]

Uh-oh. Now Felt has a problem with their AL steer tubes.

http://velonews.competitor.com/2010...-due-to-aluminum-steerer-tube-failures_124377

The lack of margin of safety in such a critical component does not make me feel that confident about the bicycle industry. Soon we will have to go back to shoving broom sticks down the steer tubes.

 

[durianrider]

I used to ride super light carbon forks that weighed under 300g but then after seeing a few crack I went back to alloy steerer. I got a specialized sequoia fork on my Caad9. It weighs a tonne but is stiff as heck. No flex like those lightweight carbon forks that you have to constantly check the steerers and worry about over clamping..plus a heavier fork is stronger and absorbs more road vibration than a lighter one. That translates to less rider fatigue=better performance overall.

There isnt a rider in the world thats race results depend on a 300g fork..but hey, its fashionable..

Save weight on your body, not on your safety parts of your bike. Gimme function over fashion any day.

 

[Black Dog]

I used to ride super light carbon forks that weighed under 300g but then after seeing a few crack I went back to alloy steerer. I got a specialized sequoia fork on my Caad9. It weighs a tonne but is stiff as heck. No flex like those lightweight carbon forks that you have to constantly check the steerers and worry about over clamping..plus a heavier fork is stronger and absorbs more road vibration than a lighter one. That translates to less rider fatigue=better performance overall.

There isnt a rider in the world thats race results depend on a 300g fork..but hey, its fashionable..

Save weight on your body, not on your safety parts of your bike. Gimme function over fashion any day.

You are 110% right about safety over weight. But if a fork is stiffer (stronger) as you say it will absorb less vibration due to less ability to flex under load. Flexy forks are more comfortable but produce poor handling.