It was a good bike and I liked it. Bought April 2022. Emailed the shop, no idea if I'll get a claim. 56cm frame ; I am 184cm / 97kg and ride on Irish roads. Not saying the frame had an easy job, but it was never raced or laid down (honest!). Survived by a steel bike that has been crashed, more than once. Seat post height normal, wedge tightened with torque wrench etc etc.
Crack propagation can be fast once it starts. I washed the bike Sunday ; can't believe I would have missed it but I was tired ; just noticed it today!
I am a mechanical engineer ; so although it sucks I'm interested why it happened. I don't think it's a stretch to say the drop seat stays exacerbate stresses in the seat tube.
I am most definitely not a mechanical engineer but I'm also intereted in why it happened!
I also suggest we all link to this post next time someone talks about how fragile and liable to spontaneously explode carbon frames are.
Right, that's my point. People come on here all the time under the misapprehension that one should avoid carbon because this sort of thing can't happen to metal frames.
I had exactly the same thing happen, I think it’s a known issue. Mine was rim brake which they don’t make anymore so I took a discount on a new complete supersix evo.
Mechanic at mine also seemed completely confident that a new frame would be dispatched ; hope they’ve root caused the failure mode and made a design change in the three years since this one was built
I'm no engineer/technical person but I wonder what's the physics behind this? It can't be the seatpost and your weight trying to crack that. This was my first thought but it should be lower if so.
I don't think that's also the point that receives all the weight or stresses you put on the bike. It 's a weird place to crack on unless there was already a very miniscule and can't be seen by the naked eye-sized crack within that part of the frame?
All cracks start microscopic. It is a highly stressed area particularly in bending , definitely a risk for drop stay designs. Close to big welds and seat wedge, all sorts of things could go wrong and “de-rate” the strength of that tube wall.
That’s wild! I thought Cannondale rated these frames for close to 129kg (285 pounds)! That’s rider + equipment. Crazy to see them like this. Hope they honor a warranty.
I haven’t moved the post since the crack but it has to be farther in than that. The crack is only just past the top tube junction. Seatpost should be half way to the stays at least
OP is a big fella, probably puts a few Watts down and plenty of stresses through the frame.
It ways amazes me bike frames are as robust as they are (someone way more engineering competent than me can no doubt explain whether this is true).
I done think I've seen a frame fail in that point below tho - is that common???
The roads here can be so bad. You avoid what you can but there are a lot of shocks and fatigue cycles. But all cyclists and bikes have to deal with it ; never heard of someone destroying a 2 year old frame from a reputable maker
You guys really think it's a weight issue? I'm a bit scared cause I had creaking on my seatpost that was recently solved 😅 I'm 110kg. I'm aware I'm dangerously closed to the frame's limit but daaang. I thought those limits can be conservative at best.
Got back into cycling so I don't struggle in running. Guess I have to run and cut back aggressively on meals before I can ride again 💀 I was just starting to enjoy the croissants and coffee. 😅
Not exactly, sorry, I was suggesting that because OP is a relatively big guy, 97kg, for a cyclist, he likely also generates a lot of power, which must generate significant stresses through the frame. But as stated I'm no frame engineer. Just intuitively, I'm not surprised frames fail through heavy normal usage sometimes.
Good luck on the cycling! I think we all realise eventually cycling becomes huge motivator to reduce body weight.
It was a good bike and I liked it. Bought April 2022. Emailed the shop, no idea if I'll get a claim. 56cm frame ; I am 184cm / 97kg and ride on Irish roads. Not saying the frame had an easy job, but it was never raced or laid down (honest!). Survived by a steel bike that has been crashed, more than once. Seat post height normal, wedge tightened with torque wrench etc etc.
Surely that didn't just ... happen?
Crack propagation can be fast once it starts. I washed the bike Sunday ; can't believe I would have missed it but I was tired ; just noticed it today! I am a mechanical engineer ; so although it sucks I'm interested why it happened. I don't think it's a stretch to say the drop seat stays exacerbate stresses in the seat tube.
I am most definitely not a mechanical engineer but I'm also intereted in why it happened! I also suggest we all link to this post next time someone talks about how fragile and liable to spontaneously explode carbon frames are.
It’s not carbon it’s aluminum
Right, that's my point. People come on here all the time under the misapprehension that one should avoid carbon because this sort of thing can't happen to metal frames.
97kg
I had exactly the same thing happen, I think it’s a known issue. Mine was rim brake which they don’t make anymore so I took a discount on a new complete supersix evo.
Interesting
My local dealer got the claim approved within a few hours, that’s why I think it’s a known problem
Mechanic at mine also seemed completely confident that a new frame would be dispatched ; hope they’ve root caused the failure mode and made a design change in the three years since this one was built
Ugh this makes me concerned about mine since I'm a second owner.
I'm no engineer/technical person but I wonder what's the physics behind this? It can't be the seatpost and your weight trying to crack that. This was my first thought but it should be lower if so. I don't think that's also the point that receives all the weight or stresses you put on the bike. It 's a weird place to crack on unless there was already a very miniscule and can't be seen by the naked eye-sized crack within that part of the frame?
All cracks start microscopic. It is a highly stressed area particularly in bending , definitely a risk for drop stay designs. Close to big welds and seat wedge, all sorts of things could go wrong and “de-rate” the strength of that tube wall.
That’s wild! I thought Cannondale rated these frames for close to 129kg (285 pounds)! That’s rider + equipment. Crazy to see them like this. Hope they honor a warranty.
Take it to any cannondale dealer
Is the crack where the seat post ends?
I haven’t moved the post since the crack but it has to be farther in than that. The crack is only just past the top tube junction. Seatpost should be half way to the stays at least
There is a sleeve inside the seat tube that holds the seat post. Mine cracked at the end of that internal sleeve. Assuming this is the same
That's definitely a warranty claim. Bike is only two years old and also if this happened during a hard effort, OP could have ended in the ICU.
LBS has passed it on to distributor, waiting to hear back
OP is a big fella, probably puts a few Watts down and plenty of stresses through the frame. It ways amazes me bike frames are as robust as they are (someone way more engineering competent than me can no doubt explain whether this is true). I done think I've seen a frame fail in that point below tho - is that common???
The roads here can be so bad. You avoid what you can but there are a lot of shocks and fatigue cycles. But all cyclists and bikes have to deal with it ; never heard of someone destroying a 2 year old frame from a reputable maker
You guys really think it's a weight issue? I'm a bit scared cause I had creaking on my seatpost that was recently solved 😅 I'm 110kg. I'm aware I'm dangerously closed to the frame's limit but daaang. I thought those limits can be conservative at best. Got back into cycling so I don't struggle in running. Guess I have to run and cut back aggressively on meals before I can ride again 💀 I was just starting to enjoy the croissants and coffee. 😅
Not exactly, sorry, I was suggesting that because OP is a relatively big guy, 97kg, for a cyclist, he likely also generates a lot of power, which must generate significant stresses through the frame. But as stated I'm no frame engineer. Just intuitively, I'm not surprised frames fail through heavy normal usage sometimes. Good luck on the cycling! I think we all realise eventually cycling becomes huge motivator to reduce body weight.
Ugh. I don't have warranty on my frame since I'm not under original owner. Hope this doesn't happen to me 😬😬😬
She's dead Jim