Can you damage a carbon frame (say cracking the top tube) by bouncing it on it's back wheel to get it dry (asking for a friend)?

[edruid]

25kg bike. Bounced up and down ~10 time about 20cm 1-2 a week for 2.5 years. Hairline cracks on sides of top tube. Cube say clamped, I say not. Anyoine have a view?

 

[Mcharza]

It shouldn't break it, otherwise you wouldn't be able to ride it even on rock garden trails.
There must be some other fault in the frame

 

[B1rdie]

Cube says clamped, you say not… what does your friend say?
Show us pictures and maybe you’ll get reasonable answers.

 

[Mikerb]

no....the tyre and suspension will absorb any shock and the top tube is fabricated to mostly withstand compressive forces ( ud mat laid along the length). Damage to a top tube is most likely to occur with twisting or clamping forces.

 

[Alexbn921]

I jump off 10+ foot drops and am 200lbs. Bottoming out the suspension at least 100 times in the last 2 years. With a 600lb spring that's over 1800lbs on the yoke, pivots and close to 800lbs on the wheels and fork.

If you drop a bike to shake off the water and it breaks, well you get the idea.

 

[RustyIron]

25kg bike. Bounced up and down ~10 time about 20cm 1-2 a week for 2.5 years.

No.

 

[Plummet]

No. Your 80ish puts far more force into the frame.

Ps clamping the tt In a work stand can. Also extension failures are common center of top tube.

 

[Plummet]

Ps pictures?

 

[Streddaz]

No, it would only be placing the bike under its own weight plus a bit of momentum. Remember, the bike should be able to handle its own weight plus up to three times that of the rider and the dynamic loading. It's either a manufacturing fault or he has clamped it and crack the frame.

 

[edruid]

No. Your 80ish puts far more force into the frame.

Ps clamping the tt In a work stand can. Also extension failures are common center of top tube.

What is an 'extension failure'?
Thanks

 

[edruid]

Ps pictures?

Top tube carbon cracking Cube Stereo 140 2020

In addition to cracking under rear shock and around pivot bearings, which happened under waranty and they dismissed. We now have this (now it's Y3 so technically out of warranty). Hairline cracks along the length of the top tube! Anyone else had this? Should I still be clattering down slopes...

www.emtbforums.com

 

[Plummet]

Top tube carbon cracking Cube Stereo 140 2020

In addition to cracking under rear shock and around pivot bearings, which happened under waranty and they dismissed. We now have this (now it's Y3 so technically out of warranty). Hairline cracks along the length of the top tube! Anyone else had this? Should I still be clattering down slopes...

www.emtbforums.com

I agree with Cube. Looks like compression clamping failure. That's not a crash damage. Who services the bike? perhaps the bike shop you purchased this off has done this? maybe a junior staff member worked on the bike. I'd dive into that rabbit hole.

 

[Plummet]

What is an 'extension failure'?
Thanks

If you nose into something ie a stupid nose heavy landing from a jump or a drop the fork tries to get pushed under they down tube. One result of this is that the tube tube tries to be ripped apart under extension.

Here's a frame I broke by extension failure 4 years ago.

 

[Rikshaw]

Was looking at buying a cube... but then saw what they believe is level of biking you can ride the bike at..

BIKE CLASSIFICATION - SUPPORT | CUBE Bikes

www.cube.eu

 

[RustyIron]

Here's a frame I broke by extension failure 4 years ago.

What brand, and what did they say when you asked them to replace it under warranty?

 

[Plummet]

What brand, and what did they say when you asked them to replace it under warranty?

Rocky mountain and it was a second hand bike and crash damage. No warranty. I didnt even ask.

 

[Plummet]

What brand, and what did they say when you asked them to replace it under warranty?

PS I fixed it, made it stronger than original and proceeded to send it off silly stuff for the next 4 years. The bike is still going strong!

 

[RustyIron]

PS I fixed it, made it stronger than original

Looks great! Nice work on the repair.

 

[RsGaz]

Was looking at buying a cube... but then saw what they believe is level of biking you can ride the bike at..

BIKE CLASSIFICATION - SUPPORT | CUBE Bikes

www.cube.eu

With the amount of reported failures, I can’t understand why anyone other than a whippet like xc racer or a sponsored rider who’s not bothered about damage, would want a carbon frame, especially someone north of 14st (of which I am 🫣) I’ll stick with my alloy Whyte thanks.

 

[Streddaz]

With the amount of reported failures, I can’t understand why anyone other than a whippet like xc racer or a sponsored rider who’s not bothered about damage, would want a carbon frame, especially someone north of 14st (of which I am 🫣) I’ll stick with my alloy Whyte thanks.

Alloy frames fail just as much as carbon ones do and it's fairly rare these day for either to fail in normal riding conditions. I've had a carbon framed enduo bike since 2015 and it's done over 10,000km, 6 years of enduro racing, may sizable crashes and never had an issue with it. Before that I had an aluminium framed bike and it cracked at the toptube/seat tube joint.
You still need to be careful clamping an aluminium framed bike because if you crush the thin wall tube the strength is greatly reduced.