Friday, June 18, 2010

Steerer Tube Failures: Trek Responds




After a rash of steerer tube failures, Trek has responded blaming incompatible stems and incorrect installation. Trek advises:
1) Always use a torque wrench, and never over-tighten stem clamp bolts.
2) Always use spacers above and below the stem. Although less obvious than correct torque, a minimum of 5mm and a maximum of 40mm spacers under the steerer, plus a 5mm spacer above the stem are required. Riders should factor in these spacers when sizing their bike.
3) Use only the stem brand and model that came with the bike, because not all stems will work with carbon steerers. Often the lighter the stem, the less chance it will be compatible with a carbon steerer. Weight-relieving cutouts on the stem clamp and steerer interface can create stress risers.
You can read the full article on VeloNews. I'd rather just have a slightly heavier bike and be able to change my stem without fear of crashing.

9 comments:

Pete Ruckelshaus said...

Serious question here...with the carbon steerer tubes apparently being th main point of failure in CF forks, why don't companies go back to using lightweight heat-treated steel, aluminum, or even titanium? Surely an ounce or two extra is worth it, given the alternative?

Anonymous said...

It may also be the China/Taiwan factor? these factories have very cheap labour but the materials are still expensive so using less carbon is how the factories cut costs.

A single layer of 150g unidirectional pre preg carbon with 35% resin content will have a weight of 202g.

You could generally say that the frames don't typically break on the joins but usually within the length of the straight tubes. Add the surface area of these tubes and you would probably not even come close to an extra 0.5m. One more layer of carbon is probably about 20-30% more carbon and would add less than 100g to a frame.

I call it China factor, all they care about is that it looks like a bike. Just a theory, do the brands really have full control of the composite construction?

Anonymous said...

It's not a China factor. It's a Trek's engineering factor. More material, better design and better quality control = safer design.

Come on, I dont think a stem cuting hole design been responsible of the failure, neither a 5mm spacer issue.

Anonymous said...

The material is NOT that expensive. The labor costs are huge, if you want a made in US frame. It is all hand layup! That is why it gets sourced to East Asia. These particular bikes are all a Waterloo, Wisc. type thing.
OCLV=Optimum Cracking, Low Value, and has since the early '90's, when Treks forks would break more often than they would hold together.
Trek going for the lawyer approved "no admission of guilt" reaffirms my opinion of them, even though I have spend 25+ years selling/working on them.
Dicks.

Anonymous said...

It's not science fiction. How can a 300 gr fork can be as strong, resistant, durable than a 500 gr fork?
----------------
"Even with the stiffer carbon chassis, Trek's engineers have managed to cleave off an appreciable amount of weight from the new Madone to the tune of about 150g. Actual weight of our bare 52cm test frame was 948g (without seat mast cap) and the matching fork just barely tipped the 300g mark."

http://www.bikeradar.com/gear/category/bikes/road/product/madone-6-series-shimano-ultegra-6700-10-35762

Anonymous said...

Typical Trek shit--the marketing tail wags the engineering dog. Consumers are freaking idiots when it comes to seeking light weight. A responsible bike company would build the bike right, lie about the weight in the catalog, and the customer would be happy and safer with it on the road.

Anonymous said...

i believe, down the road, at least one of the individuals admitted that he didn't use a torque wrench to tighten the stem bolts. c'mon folks, Ritchey makes a $20 Torque Key that set at 5Nm. way cheaper than a new fork, new frame, new teeth, or worse. things work if you aren't stupid.

Anonymous said...

^ That was probably the only reasonable post here.

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