Pro carbon after crashes

[Rob3rt]

Carbon tube is immensely strong in tension and under bending forces. Hit it sideways with something though and it can crush quite easily, as can thin-walled steel or alloy tubing.

My buddy's chainstay after his bike bounced off the front of a car and flew 15 feet over my head to land on top of a hedge:

Not as easily as people often suggest though!

 

[screenman]

When I used to race ie when I used to crash, it was common for the bars to end up swinging back to dent the top tube. On 531 that wasn't a problem but I imagine it would be for carbon, both the frame and the bars

Big problem, any tube that is dented is weakened.

 

[Flick of the Elbow]

Not a big problem at all, my Mercian race frame has got dents on both sides of the top tube and is still going strong 20 years later. Plus you usually get warning if steel is about to fail.

 

[screenman]

Not a big problem at all, my Mercian race frame has got dents on both sides of the top tube and is still going strong 20 years later. Plus you usually get warning if steel is about to fail.

The dented area is now the weakest part of the tube, the crown around the dent creates an uneven pressure.
Try bending a copper tube, now put a small dent in it and bend and you will get my point.

 

[MikeG]

I have seen a video in which carbon frames were tested to destruction, and aluminium frames were submitted to exactly the same regime. It is eye-opening, as the carbon frames were many times stronger than the aluminium, having survived far better and far longer having weights dropped on them from a measure height.

So you start with a false premise, I'm afraid. Carbon frames aren't delicate.

This is a longer version of the video I remember.

 

[Flick of the Elbow]

Well I'll take my chances with visibly dented steel over visibly sound but potentially structurally weakened carbon any day

 

[screenman]

Well I'll take my chances with visibly dented steel over visibly sound but potentially structurally weakened carbon any day

My turbo bike has a Dent in the top tube and is not some thing I worry about. I was just being pedantic in pointing out a dented tube is weaker than a non dented.

 

[Smokin Joe]

Pro teams probs have access to the factory carbon testing and x-ray stuff.

I'd like to know where this oft repeated story comes from. The reality is a mechanic picks the bike up, checks for damage and if there is none visible hands it back to the rider and forgets all about it. When do you ever see an X-Ray unit in the caravan of a Grand Tour?

 

[screenman]

I think they have a pair of those glasses they used to sell in Beano, Dandy and other such comics.

 

[fabregas485]

Surely the frame needs to meet the same standard that aluminium would in order to be legal to use? (I have no idea if pro bikes have standards they must meet, but I would imagine they would)

 

[disabledcyclist]

That video is a REAL eye opener

 

[MikeG]

That video is a REAL eye opener

Yep.

Before seeing that I was going for another aluminium bike. After seeing that, I bought carbon fibre.

 

[Beebo]

Not as easily as people often suggest though!

As shown in the video posted by @MikeG.
At 5min 20seconds they're swinging a carbon frame into a concrete block, and they cant break it.

 

[Hacienda71]

As shown in the video posted by @MikeG.
At 5min 20seconds they're swinging a carbon frame into a concrete block, and they cant break it.

That bit made me laugh. Definitely not a normal force applied to a frame through riding but strangely not an instant disintegration.

 

[Flick of the Elbow]

"Not an instant disintegration"

Yes that's the bit that would bother me, the apparent resilience but just waiting to crumple up on your next high speed descent.