the way that's fracture it looks like a bad casting that caused the fail.
Out of curiousity, because of the flat part or the rough part?
Replace your pedals
Out of curiousity, because of the flat part or the rough part?
rough part
We don't know what our limits are, so to start something with the idea of being limited actually ends up limiting us.
Ellen Langer
2 years, that's not very long. Doesn't seem right. And seems like a funny place to break.
Lots of my days this year have been on b-line and easy does it as my 9 and 11 year old daughters are riding and are reach over 10 days in the park now too.
I have never worried about pedals before. But now… I may replace everyone on every bike.
Out of curiousity, because of the flat part or the rough part?
Judging by the picture on my crappy computer screen, that is some heavy porosity on the right side, and the failure shear on the left.
Pastor of Muppets
I should take my Scarabs apart to have a look at them when I get home. I'm interested in looking at the axle and that taper.
Porose metal isn't good
Why slag free swag?:rolleyes:
ummm, as your doctor i recommend against riding with a scaphoid fracture.
Heat treatment problem maybe. It should bend not snap.
Judging by the picture on my crappy computer screen, that is some heavy porosity on the right side, and the failure shear on the left.
I don't think so. The smooth part is probably a fatigue crack. A closer inspection will probably reveal beaching marks. Once the crack reached what looks like 1/3 of the way through the axle was no longer strong enough and failed. The rough part is brittle fracture. This type of failure happened suddenly across the remaining pedal axle along the grain boundaries (which is why it looks like sugar crystals).
My guess is that there was a small flaw in the axle that created a stress riser. This initiated a crack which propagated across the axle under repeated loading. In other words, a very classic fatigue failure. Have Bog look at it and I'm sure he'll give you a pretty good analysis of why it failed.
Unfortunately it is also difficult to inspect such parts for this type of failure. You "might" be able to spot the crack upon disassembly, cleaning and close inspection. I also wouldn't expect a pedal axle to fail so quickly either.
Heal up fast and strong Ken! Sleep lots and rest your brain.
I don't think so. The smooth part is probably a fatigue crack. A closer inspection will probably reveal beaching marks. Once the crack reached what looks like 1/3 of the way through the axle was no longer strong enough and failed. The rough part is brittle fracture. This type of failure happened suddenly across the remaining pedal axle along the grain boundaries (which is why it looks like sugar crystals).
My guess is that there was a small flaw in the axle that created a stress riser. This initiated a crack which propagated across the axle under repeated loading. In other words, a very classic fatigue failure. Have Bog look at it and I'm sure he'll give you a pretty good analysis of why it failed.
Unfortunately it is also difficult to inspect such parts for this type of failure. You "might" be able to spot the crack upon disassembly, cleaning and close inspection. I also wouldn't expect a pedal axle to fail so quickly either.
Heal up fast and strong Ken! Sleep lots and rest your brain.
yeah, but steel will typically bend, then tear, not fracture. with how clean that break is at the smooth part, particularly at the edges, it seems that this was a sudden failure, not something you would expect to be slowly happening over time.
my money would still be on a bad cast and when the shit 2/3rds reached it's limit the good 1/3 let go real quick.
either way, i'm real curious to see what the final say is on proper inspection by someone who's qualified to give a definitive answer.
We don't know what our limits are, so to start something with the idea of being limited actually ends up limiting us.
Ellen Langer
yeah, but steel will typically bend, then tear, not fracture. with how clean that break is at the smooth part, particularly at the edges, it seems that this was a sudden failure, not something you would expect to be slowly happening over time.
my money would still be on a bad cast and when the shit 2/3rds reached it's limit the good 1/3 let go real quick.
either way, i'm real curious to see what the final say is on proper inspection by someone who's qualified to give a definitive answer.
not if it is heat treated , been a machinist for 28yrs and i have seen many clean breaks on many shafts of all types of materials . a hard landing could cause that to snap
whats the rest of the pedal shaft look like may have snap on a undercut machined into the axle
#northsidetrailbuilders
not if it is heat treated , been a machinist for 28yrs and i have seen many clean breaks on many shafts of all types of materials . a hard landing could cause that to snap
whats the rest of the pedal shaft look like may have snap on a undercut machined into the axle
yeah true, and one would think that it is heat treated.
ps - i'm basing my thoughts off of limited time in a machine shop.
We don't know what our limits are, so to start something with the idea of being limited actually ends up limiting us.
Ellen Langer
a hard landing could cause that to snap
this sounds like a stupid question, but I'll ask it anyways.. Are hard landings cumulative on metal? I mean we aren't multi ton machines but meat bags on metal….
Where he was riding at the time has zero hard landings… And now makes me nervous.
Looks like a warranty claim.
It is easy to dodge our responsibilities, but we cannot dodge the consequences of dodging our responsibilities.
- Josiah Stamp
Every time I see an adult on a bicycle, I no longer despair for the future of the human race.
- H.G. Wells
this sounds like a stupid question, but I'll ask it anyways.. Are hard landings cumulative on metal? I mean we aren't multi ton machines but meat bags on metal….
Where he was riding at the time has zero hard landings… And now makes me nervous.
i am the furthest from a expert in materials but have hands on experience most don,t from being in the jobber trade , meaning lots of industrial repairs .
but here goes , all material has memory so it will naturally want to return to it,s natural state when flexed .
when flexing on impact a surface imperfection can result . over time and repeated cycles it can grow eventually developing into a crack further on the skin of the material . once the imperfection is at a certain level it will not return back to it,s natural state and will stay in a bent state until the next hard impact causing failure .
to me looks like it cracked and then failed shortly after a impact .
#northsidetrailbuilders
Well, I destroyed a 4 ride old D3 evo. Suffered concussion and bruises. Was unconscious for a bit. But, will pull through no problem.
Shit…. so sorry. That is not something to laugh about. Glad you are going to be OK. Critical part failures on our bikes are not acceptable. I would follow up with the Chromag boys on this one.
thanks for the reminder tho, i think it's easy to forget about stuff like that.
I prefer to forget about stuff like that. Biking is expensive enough without replacing perfectly good parts out of unwarranted fear of one off failure.
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