Speaking of carbon fiber failures

[fa63]

This came in to our shop today. Customer said the bike simultaneously snapped in four places (both the chain and staystays) when he stood up to pedal on a 10% grade. First time I have ever seen anything like this; customer said it was JRA and I don’t know the history of the bike.

On a positive note for internal cables; they sort of held the rear end together!

[hoj]

I have nothing really to add other than... wth?!?!?

[buddybikes]

Least there is more frames available than components these days...

[duff_duffy]

Did he weigh 5000lbs? I thought only there bars were designed to snap.

[fa63]

I would guess him to be no more than about 80 kg / 175 lbs

Originally Posted by duff_duffy

Did he weigh 5000lbs? I thought only there bars were designed to snap.

[C40_guy]

That will buff right out.

What brand was it?

[Louis]

Wow.

Did the guy happen to be Magnus Backstedt?

Edit: I see the weight question has already been answered above.

I'd guess either previous damage of some sort or serious manufacturing defects.

Normal frames (of any material) just don't do that.

[glepore]

Its sitting on a Canyon box and the dt appears to have a Canyon logo.
I'm suspicious of the JRA story.
Some FOD got wedged somewhere, or worse.

[jimoots]

Originally Posted by glepore

i'm suspicious of the jra story.

+1

Difficult to comprehend a frame failing in the four spots simultaneously and catastrophically due to a manufacturing defect. Like sure you can get a crack somewhere on the chainstay and other three points of the system (other chainstay, seatstays) will flex, you'll get some weird sensations from the wheel moving around... but a seemingly clean snap of all four stays seems to indicate the story is a bit off, looks much more like crash/impact damage. We'll never know of course!

[duff_duffy]

What’s JRA? Just riding along?

[gasman]

Just Riding Around but Just Riding along works also

[prototoast]

Originally Posted by jimmy-moots

+1

Difficult to comprehend a frame failing in the four spots simultaneously and catastrophically.

My guess is one of the chainstays had been weakened by a prior incident. It snapped, and then the second chainstay wasn't strong enough on its own, so it snapped. At that point, the rear wheel started to slip back and snapped both seatstays.

It may seem almost "simultaneous" to the rider, but in practice it was almost certainly sequential.

[Louis]

Originally Posted by duff_duffy

What’s JRA?

It's the most common cause of failure of bike frames and components, except perhaps due to neglect and abuse. (but the latter two are almost never self-reported)

[jimoots]

Originally Posted by Louis

It's the most common cause of failure of bike frames and components, except perhaps due to neglect and abuse. (but the latter two are almost never self-reported)

Chiming in to add JRA failures often tend to be caused by neglect and abuse tee hee

[Louis]

I just figured out the root-cause - the disc brakes.

Had it been a rim brake frame the seatstays would have been reinforced in that area and never failed, preventing the chain reaction failure of the other stays.

(just to clarify, that's ^^^ a joke)