Snapped crank spindle.

[cyberknight]

Had the exact same thing happen , luckily a hedge was on one side and I was going fast so the hedge stopped me falling over

 

[SkipdiverJohn]

Rolls out the 'you don't get that with square taper' bottom brackets !

I've never heard of a square taper failure though. Or a cottered crank BB axle failure either. No doubt the odd one happens but they must be incredibly rare. On the other hand the shite engineered hollow axle weight weenie stuff seems to fail quite regularly without warning.
What caused the actual crash though, was the OP riding standing up at the time of failure? Since the non drive side detached it doesn't look like the transmission jammed solid.

 

[Angus McCoatup]

Dont know @SkipdiverJohn . For a split second my left crank wobbled slightly then my head was in contact with the road. It all happened so fast I had no time to slow up or do anything.

 

[davidphilips]

Have seen hollowtech crank arms come lose if not tighten correctly and even seen a l/h arm splines worn from again not being tightened correctly but held on by the fail safe but thankfully never seen one fail like that.

Have even seen the latest shimano cranks become unbonded but again not leading to rendering the bike a danger, even seen carbon crank arms break but perhaps they had a knock at some time?

That is quite a worry and really dont know how any one even a lbs could detect a fault like that with a crank arm?

Thank goodness apart from a very badly bruised arm you are ok could have been a lot worse.

 

[Illaveago]

What got me was I had no time to react. I have had a crank come loose before due to it not being properly tightened, and had chance to stop. But this time, wallop. Straight off.

I'm glad you are alright.
It's not nice when you suddenly hit the deck unexpectedly!
I came off last year when a pedal came off .

 

[Ming the Merciless]

For those who take their hollow tech cranks off and have them x rayed. Where do you get this done, do you have your own Park Tools x ray machine or does the LBS have one?

 

[nickyboy]

£2,180
With the added benefit that you can check your fillings at the same time

 

[rogerzilla]

They're easy to remove and check for cracks, at least on the outside of the spindle. However, I don't know how quickly a crack propagates in the steel used. If it's very hard and brittle, it could break from almost nothing.

Contributory factors could include rust, and sticky bearings causing the crank to slide against the inner bearing race.

 

[Angus McCoatup]

New helmet and crank arrive today. Back in the game!! 😆😆

 

[I like Skol]

New helmet and crank arrive today. Back in the game!! 😆😆

Straight back on it, like

Unlikely to happen again, but I bet you pay attention more closely next time you think your bike is making a new noise.....

 

[Angus McCoatup]

@I like Skol an audible warning would have been a distinct advantage 😆

 

[Ridgeway]

For those who take their hollow tech cranks off and have them x rayed. Where do you get this done, do you have your own Park Tools x ray machine or does the LBS have one?

Until recently i just carried mine in my trolley case and went through the airport, they do it for free

 

[HMS_Dave]

This is why part of my pre ride checks is hitting every component with a hammer and if it drops off, it goes in the bin and I carry on. It's just a pity my bin is full of cycle helmets at the moment....

 

[Ming the Merciless]

This is why part of my pre ride checks is hitting every component with a hammer and if it drops off, it goes in the bin and I carry on. It's just a pity my bin is full of cycle helmets at the moment....

You'd better hit the bin with a hammer to make sure it’s ok.

 

[ColinJ]

You'd better hit the bin with a hammer to make sure it’s ok.

And buy a second hammer to check the checking hammer!

As for warning noises... I was sprinting up a short steepish hill on my singlespeed bike last year when I heard a strange clicking sound. I didn't want to 'do a Duncroft Avenue' so I sat down and just as I was safely back on the saddle my chain snapped!