I’ve put 20,000ish miles on this but I still can’t believe this happened. Any reason for a break like that? I would really prefer to prevent it in the future…
by MocoPDX
I’ve put 20,000ish miles on this but I still can’t believe this happened. Any reason for a break like that? I would really prefer to prevent it in the future…
by MocoPDX
13 Comments
that’s…. surprising. checked with the bike shop for a warranty yet ? I don’t know if it’ll be covered 4 years after purchase but it wouldn’t hurt to ask them.
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I have no idea what the reason is – but man if you’re not injured and didn’t have a bad crash I’d be just thankful it wasn’t more serious.
I guess in terms of reasoning it could have been caused by a fracture from over tightening the clamp, or a small crack that got worse and eventually failed etc. That’s all I can think of
That sure looks like a lot of post above the frame. Wheres the maximum height line?
20 k miles is a lot–it’s good to inspect everything carefully for any signs of cracking before you get there. A contributing factor could be the length of exposed post–the modern style of having a sloped top tube and a long seatpost instead of the traditional “fist full of seat post” exposed with a straight top tube improves comfort by adding compliance with a flexy seat post, but that flexing is also accumulating fatigue. Fortunately people have rediscovered that pneumatic tires are a great way to add compliance, so maybe we’ll go back to shorter seatposts. In the meantime, inspecting more often or even replacing at 10k miles would probably prevent this from ever happening again.
One of the reasons why I was looking for a carbon frame with generic 27.2mm seatpost. Makes replacing them much simpler and likely less expensive.
On topic, 20,000miles is already a fair amount, but this still shouldn’t happen in my opinion. Unless it’s been overtightened or been in a crash there’s very little you can do to prevent this type of failure.
Please show us the min/max lines on the post.
Is it rusted?
Is it past the max level?
Assuming none of these, shitty for Cannondale not to warranty it. I understand it’s past the warranty period, but I haven’t heard of any manufacturer not doing a courtesy warranty on a safety break like this.
I had a pedal/PM snap once, well beyond the warranty period, they overnighted a pair and sent a few apologies (they also sent me a return box to send it for inspection).
crack n fail still alive and well in 2024
20k miles is a fair amount, but a seat post on a road bike should last as long as the frame if properly cared for. From the look of it, there is a lot of seat post exposed, every post has a minimum insertion level. Another factor may be over tightening the seat clamp. Most bikes will recommend a maximum torque level but you do not need to tighten that much. Using carbon grip paste will allow you to use much less torque and lock the seat post in place, particularly on a road bike, slipping is not that likely, even if you are one or two Nm away from the max torque. I also like to regularly take my seat post out clean it, check it and put it back. Dirt and grime can build up in the space between and start to damage the carbon. It also gives you early warnings if anything is starting to crack.
Cyclejockey likes this.
That’s why I only ride Chinese carbon.
It looks like there’s been a crack there for a while – the narrow bit at the front is darkened, suggesting that it first cracked a while ago.