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Well, yes, clearly not a sticker but interested if any materials science type experts or armchair experts have any input as to why this has failed?
Its a 13mo old 6061 alloy single pivot frame. Crack is above the top of the main triangles shock mount.
My knowledge recall from my 1st year mech eng material science is weak.
I embarrassingly have no idea how long its been like this but as soon as it was seen, the bike was filed away under "don't ride". Its not been crashed. This is from technical trail and flowy jump trail riding. Looks like I should've caught it sooner as doesn't look like its fresh..
Poor weld (too hot)?
Not heat treated?
Shit happens?
Hoping to avoid brand identification just now (please don't take this as a challenge) as I've been offered 50% crash replacement but I was expecting a no questions warranty.
pic link
Cracked in the weld HAZ, no sign of impact. Should be warranty replacement.
Poor form for the manufacturer not to warranty that.
Poor weld and poor design. Was there a seat post shim?
Fatigue cracks initiated at the weld toe.
How long is the warranty? If its within warranty why no replacement? (assuming its not crash damaged)
How far down does the seat post go down past the weld? It's a pretty obvious place for fatigue failure to occur due the flexion of the seat tube - nothing to do with the weld, just what happens when stresses are concentrated in one particular area.
I’d say after 13 years use getting offered 50% off is a very good offer !
That’s cracked above shock mount on down tube isn’t it ? High stress area
I’d say after 13 years use getting offered 50% off is a very good offer !
Months
Oops carry on yes full warranty !!
This is forward downtube shock mount. Not seat tube.
12mo warranty. Bike is technically outside that period but I'm certain that hasn't happened since month 12.
Not sure how no GB eurozone companies have to address fit for purpose, consumer rights etc.
We're you in the EU when you bought it or did you buy it outside the EU and bring it in with you?
Purchased direct from the brand online who shipped it over to me here in North America.
Ah, not familiar enough with your rules and whether they need to abide by local regulations when selling into that market.
Either way, 12 months is a pretty crap warranty.
Yeah, that’s a design/manufacturing fault. European sale of good act gives you a 2 year warranty, even if you are not in Europe.
That isn't a stress or strain style crack from use, that's failing around the welds, so caused during the manufacture and the weakening of the parent material during the welding process, either through something like cold cracking, or some type of gaseous build up in the joining area during welding, can't see how the company can argue that it's not a manufacturing defect due to location and physical appearance of the cracks.
Agree with what's been said, 50% off isn't great back up from the manufacturer... Even "if" technically just outside of warranty.
That isn’t a stress or strain style crack from use, that’s failing around the welds,
I'm not a metallurgist but stress in use is what causes cracks at weld edges after a period of use, even in a good frame. It happens at weld edges as that's where stresses usually concentrate - I expect you know that from what you're saying about the process. It might be bad weld process also, speeding it up, or a combo of both.
It's the upper shock mount weld on a single pivot bike and repeated bottom-out or running a much higher sprint rate could cause it. It shouldn't and I'm not suggesting that is the cause, but in theory you could do that. Could simply be a bad weld that's gone through the tube so the mount isn't well supported. Other causes might be insufficient wall thickness and/or overall tube stiffness there to withstand the stress concentrations, if that's the case you'd expect to see a few more similar failures on that model.
Manufacturing fault.
The weld doesnt weaken the metal around it, it makes it slightly harder, and causes stress around it when in use, as the weld is the strong part now, and the tube is far weaker.
Heat treatment of the frame will usually help after welding, as it'll 'temper' the tubes, make them slightly softer, and thus more able to flex just that little bit more than a harder tube.
Could be a design fault, but no heat treatment after welding has probably been the biggest cause.