Don't you just love that feeling?

[st_lupo]

...when you wipe out in the middle of a turn and while flailing around in a cloud of snow, you realize only one boot is attached to the board?  Fortunately it was my back binding that gave up so I can keep myself off the AIL.

Don't suppose any of the mechanical engineers can read anything from the fracture pattern?  It was an F2 Race Ti from 2015.  Needless to say I am replacing all of the bails on my bindings asap! At least I've got a pair that are a few years newer that I will use while waiting for parts.  

[snowburn]

glad your ok

[dhamann]

2 or 3 years old. heel. just heard a pop and pulled over to side. no wipe out. side slipping with one foot for 90% of the way down isn't all that fun though. i feel your pain. it happens. the breaks seem to be at the bends. check those T-nuts too as mentioned in other posts. glad you didn't get hurt.

[wulf]

@st_lupo that's a typical picture of a longterm dynamic fatigue failure. The crack started some time ago (8 o'clock region) propagated slowly due to dynamic load until the remaining cross section could not bear the load anymore  (2 o'clock region). That's when it cracked. Known failure mode with metals.

Same with @dhamann case

Regularly check ALL parts of the binding. Replace when in doubt.

 

Edited February 6, 2022 by wulf

[bigwavedave]

7 minutes ago, wulf said:

@st_lupo that's a typical picture of a dynamic fatigue failure. The crack started some time ago (7 o'clock region) propagated slowly due to dynamic load until the remaining cross section could not bear the load anymore  (1 o'clock region). That's when it cracked. Known failure mode with metals.

Same with @dhamann case

Regularly check ALL parts of the binding. Replace when in doubt.

 

If it's typical, what are you looking for. You can see a crack in the metal "for sometime" before it fails?

I've heard that racers regularly replace F2's, like every season. Not sure if they look for predictors of failure before retiring them.

Glad you're okay @st_lupo. I've had 2 front binding failures in 2 years, luckily no serious injury. Only had one binding failure before that, 30 yrs ago.

[Corey]

11 minutes ago, bigwavedave said:

If it's typical, what are you looking for. You can see a crack in the metal "for sometime" before it fails?

You can usually see a crack before it fully fails, but it takes a dedicated inspection. Clean part well, have good light and magnification, and meticulously check every single square millimeter. (Square 1/32"? Doesn't flow off the tongue as nicely in USA units! ) 

Something like this in the inside of a bend will be tough to see - and there may be forming lines from the bending jig that add confusion. Dye penetrant testing helps, but that stuff is expensive! 

This inspection process is what makes planes and race cars so expensive! Light & highly stressed parts need replacement or inspection intervals. We're lucky that bails are relatively cheap and don't fail often. 

I should add: What's interesting is that the bail was cracked about 2/3 of the way through before that fateful turn! As Wulf mentioned, it spread slowly over the whole flat-ish area until only the rough crescent of material remained at the top right. Then one final load was enough to tear that apart. 

That crack was likely visible for a while, especially when the bail was tensioned with a boot clamped up in it. 

[wulf]

38 minutes ago, bigwavedave said:

If it's typical, what are you looking for. You can see a crack in the metal "for sometime" before it fails?

I've heard that racers regularly replace F2's, like every season. Not sure if they look for predictors of failure before retiring them.

Glad you're okay @st_lupo. I've had 2 front binding failures in 2 years, luckily no serious injury. Only had one binding failure before that, 30 yrs ago.

Indeed not so easy. You barely see anything at the very beginning. Later when the crack already has a bit propagated the method @Corey mentioned (tensioning the binding with a boot clamped) should give some hints. I had that only happening once. I could hear some "clicking" sound while riding while applying pressure. At that time I could not sort that out. 1 season later the rear bail of the rear binding gave up. 

Edited February 6, 2022 by wulf

[st_lupo]

I didn’t lay it on too thick at home but still got a consolation bike ride (the other winter carving)  

Kinda scary how common this failure mode is and I had no idea.  Will add that check to my routine along with the t-nuts.  Anything else???

i’ve sent emails to carvers.si, yyz, carversparadise and F2, anybody else I should hit up for bails?  I might just spring for a pair of TD3s and spare parts next time  I’m in the US.  Which parts wear out earliest on them?

 

[bigwavedave]

1 hour ago, st_lupo said:

I didn’t lay it on too thick at home but still got a consolation bike ride (the other winter carving)  

Kinda scary how common this failure mode is and I had no idea.  Will add that check to my routine along with the t-nuts.  Anything else???

i’ve sent emails to carvers.si, yyz, carversparadise and F2, anybody else I should hit up for bails?  I might just spring for a pair of TD3s and spare parts next time  I’m in the US.  Which parts wear out earliest on them?

 

Love the fat tire biking, but not near as much as carving.

I'm not sure if you can get just the bails for F2's, but since there are some other posts about the plastic  sliders failing too, it would make sense to replace the whole toe/heel block assembly. 

On the td3's it seems the most common failure is at the top of the threads on the bails and sometimes the lugs. From another thread here, the takeaway for me was to disassemble all the lug/bail joints annually looking for any frozen threads. Replace ones that don't spin freely and reassemble with either anti-seize grease or thread tape. 

5 hours ago, Corey said:

I should add: What's interesting is that the bail was cracked about 2/3 of the way through before that fateful turn! As Wulf mentioned, it spread slowly over the whole flat-ish area until only the rough crescent of material remained at the top right. Then one final load was enough to tear that apart. 

That crack was likely visible for a while, especially when the bail was tensioned with a boot clamped up in it. 

Cory, was this on your td3's? or F2's?

[Corey]

33 minutes ago, bigwavedave said:

was this on your td3's? or F2's?

I'm talking about st_lupo's F2 failure above, but all fatigue failures in metal work like this. They sit there with a crack growing microscopically with every load cycle, unnoticed, until the remaining material can't take the load and it snaps in a ductile failure. 

The science on this stuff goes deep. The short version is that if you want something last forever, make it so strong that it's never stressed high enough to start that initial crack - even at the weakest point like a material defect or a scratch. That makes stuff HEAVY! 

This comes back to the Engineer's saying: Strong, light, cheap. Pick any two. 

@st_lupo, I don't think I'd run TD3s if I were in the EU. As much as I love them, F2s are the standard by which all are judged and are a whole lot cheaper in the EU. Just replace bails and T-nuts a little more often. 

[bigwavedave]

1 hour ago, Corey said:

I'm talking about st_lupo's F2 failure above, but all fatigue failures in metal work like this. 

Ahhh, deduced from lupo's  photo. 

[st_lupo]

Thanks for all the great info.  It doesn't seem to be possible to buy only the bails, but I can find the entire toe-block in Europe (I would be pretty steamed if I had splashed out on the CNC version of the bindings). 

 

@Corey: is there any low-cost source of LPI testing stuff?  The theory on wikipedia seems simple enough and I'm wondering if some kind of penetrating oil (WD-40) and talcum powder would be better than just a plain surface inspection?

 

 

[Corey]

3 hours ago, st_lupo said:

I'm wondering if some kind of penetrating oil (WD-40) and talcum powder would be better than just a plain surface inspection?

That's an interesting idea! It probably would work.