Snapped spindle

[roubaixtuesday]

On the commute

https://www.cyclechat.net/threads/tales-from-todays-commute.105055/post-7567940

I'm sure I saw someone else post one recently.

It's been on since the bike was new, 10 years and at a guess 40,000 plus miles but still a bit of a surprise.

They don't make them any more I think (5800) but surprisingly managed to score one off Ebay for a princely £80 and even in silver and 175 length (Yes, it's silver under the commuting crud).

Probably worth getting a new BB too I guess, and will replace chain and cassette too, which ideally I'd have waited until vernal equinox for.

 

[wafter]

Bugger - that's concerning and yes; while not common it seems a few such failures have cropped up on the internet now.

It's worrying that these are failing at all in normal use and raises the question of how many more are likely to go the same way as this relatively recent standard for crank axles ages.

Have you cleaned it up and looked for any obvious initiation points - pitting from corrosion etc?

 

[Ajax Bay]

I saw someone else post one recently.

https://www.cyclechat.net/threads/crank-spindle-broken.309161/page-3
There'll be over a million of these Shimano cranksets with the attached spindle in an H2 BB. This one was 40k km in. I wonder what the MTBF but it has to well exceed the number of km which the vast majority ever see in use.

 

[silva]

If an axles design is up to the task then breaks should have clear external causes like overloaded, pothole, so on. But the load here comes from a human leg...
The torsion deformation is a function of outer and inner diameters of the shaft ( thickness wall). The outer is bound within dimensions for compatibility with other parts, but is there any limitation for the inner?

 

[richardfm]

If an axles design is up to the task then breaks should have clear external causes like overloaded, pothole, so on. But the load here comes from a human leg...

The design could be fine, but there would be a manufacturing flaw that wasn't picked up in QA

 

[Yellow Saddle]

Bugger - that's concerning and yes; while not common it seems a few such failures have cropped up on the internet now.

It's worrying that these are failing at all in normal use and raises the question of how many more are likely to go the same way as this relatively recent standard for crank axles ages.

Have you cleaned it up and looked for any obvious initiation points - pitting from corrosion etc?

Nope, not concerning. Everything fails eventually. This is just one of those on the wrong side of 99.9999% success rates even after high mileage. The internet amplifies failures and mutes successes. That design is by far the best the bike industry has come up with in 100 years. Hollowtech has been around for at least 20 years, with millions of bikes doing zillions of miles each year.

 

[silva]

The design could be fine, but there would be a manufacturing flaw that wasn't picked up in QA

Hollowtech is of the era of metallurgy, computer, automation and batches, a flaw in a single product points more outside the manufacturing than inside.
A design that saves about 130 grams and absorbs/wastes a couple percent less leg power, at the cost of a scratch that leg power can grow to break in two (remember the delaminating "hollow crank" mass fail story), well, I'd rather name it a fine bucks design
2-3 times the cost, critical mount requirements, and with vulnerabilities alike this axle one, and external and thus more exposed bearings, where 1 unit of sand suffices just like a scratch as "death trigger".

Hollowtech was a legit way to cheat (weight, mechanical efficiency) in races, until all rode hollow.
But outside racing... 130 grams being like an apple less in the pocket - what difference does it make, other than doubling to tripling bikes maintenance cost, and failure out there in the great wide open?

It's of course by far the best design the bike industry has come up with in 100 years.
Just imagine they hadn't, cheapo and more robust/sealed>reliable square taper had stayed the mass' norm, and allow DIY (just a crank puller as special tool), the bike industry would have missed gazillions of bucks.
For racing ofcourse, to further break records, to win, or to keep up with the hollow rest, it's now a necessity.
Just imagine the weekly sunny sunday tour with pub stops, and you arrive 5 minutes after the hollow riders, and that everytime again, that's annoyant.
... that's what I think about it, using bike as a training and a transport.

 

[roubaixtuesday]

Hollowtech is of the era of metallurgy, computer, automation and batches, a flaw in a single product points more outside the manufacturing than inside.
A design that saves about 130 grams and absorbs/wastes a couple percent less leg power, at the cost of a scratch that leg power can grow to break in two (remember the delaminating "hollow crank" mass fail story), well, I'd rather name it a fine bucks design
2-3 times the cost, critical mount requirements, and with vulnerabilities alike this axle one, and external and thus more exposed bearings, where 1 unit of sand suffices just like a scratch as "death trigger".

Hollowtech was a legit way to cheat (weight, mechanical efficiency) in races, until all rode hollow.
But outside racing... 130 grams being like an apple less in the pocket - what difference does it make, other than doubling to tripling bikes maintenance cost, and failure out there in the great wide open?

It's of course by far the best design the bike industry has come up with in 100 years.
Just imagine they hadn't, cheapo and more robust/sealed>reliable square taper had stayed the mass' norm, and allow DIY (just a crank puller as special tool), the bike industry would have missed gazillions of bucks.
For racing ofcourse, to further break records, to win, or to keep up with the hollow rest, it's now a necessity.
Just imagine the weekly sunny sunday tour with pub stops, and you arrive 5 minutes after the hollow riders, and that everytime again, that's annoyant.
... that's what I think about it, using bike as a training and a transport.

 

[Drago]

Hollowtech is of the era of metallurgy, computer, automation and batches, a flaw in a single product points more outside the manufacturing than inside.
A design that saves about 130 grams and absorbs/wastes a couple percent less leg power, at the cost of a scratch that leg power can grow to break in two (remember the delaminating "hollow crank" mass fail story), well, I'd rather name it a fine bucks design
2-3 times the cost, critical mount requirements, and with vulnerabilities alike this axle one, and external and thus more exposed bearings, where 1 unit of sand suffices just like a scratch as "death trigger".

Hollowtech was a legit way to cheat (weight, mechanical efficiency) in races, until all rode hollow.
But outside racing... 130 grams being like an apple less in the pocket - what difference does it make, other than doubling to tripling bikes maintenance cost, and failure out there in the great wide open?

It's of course by far the best design the bike industry has come up with in 100 years.
Just imagine they hadn't, cheapo and more robust/sealed>reliable square taper had stayed the mass' norm, and allow DIY (just a crank puller as special tool), the bike industry would have missed gazillions of bucks.
For racing ofcourse, to further break records, to win, or to keep up with the hollow rest, it's now a necessity.
Just imagine the weekly sunny sunday tour with pub stops, and you arrive 5 minutes after the hollow riders, and that everytime again, that's annoyant.
... that's what I think about it, using bike as a training and a transport.

Yours sincerely, Derek Suntour.

 

[fossyant]

Yours sincerely, Derek Suntour.

I really would take what he says with a massive pinch of salt seeing he runs bikes into the ground with snapped cassette and sprocket teeth, snapped frames, and uses motorbike chains.

 

[Drago]

Trust me, not so much as a grain of salt.

 

[silva]

I really would take what he says with a massive pinch of salt seeing he runs bikes into the ground with snapped cassette and sprocket teeth, snapped frames, and uses motorbike chains.

You're free to verify the things I've written.
Because all your post has, is a deny.

Then your further irrelevance:
Your 1) About my "snapped cassette", I don't have any, it's 1 sprocket front, 1 sprocket back.
At the moment, the former has > a quarter of its 47 teeth broken off in the middle en some even filed down to their bottom. That's since 3 years (a part broke off earlier), at 50 km daily.
The rear sprocket has 16 of its 16 teeth broken off in the middle, that's since half a year, and it's a secondlife sprocket that I replaced 7 years ago due to too thin (I thought) teeth risking breaking off, and decided to mount again, to see if the front sprocket story repeats.
It did repeat.

That proves that replacement wasn't needed, and that singlespeed sprockets could be designed with half as high teeth and valleys as wide as a max worn chain wears out.

Your 2) My frame, as explained elsewhere on this forum, broke for a reason I had nothing to do with: a design (by itself losening frame slot for belt application) and a production error.
The latter: rear wheel not in line with front - my rear tyres wore out of center since bike acquisition back in 2017, upto the point that I started to flip them on the rim, to achieve a 1 year life span.
Since the replacement frame, tyres wear in the centre.
I contacted the frame manufacturer about it, and the explanation he gave me was that my frame must have been produced "at the edge" of the allowed tolerance.

Your 3) The motorcycle chain on it, is just, and again, a result of trying things out as to achieve longer drivetrain life and thus less costs, work, and misery.
It proved as
How: by indeed making drivetrain live longer.

All above is not about theories and thoughts.
It's about proven practice.

I posted here some remarks on the HT axle breaks reports.
What did you do here: raise a kinda "BadGuy" general criticism flag.
Zero relevance to the subject.
What's your win, your loss, your whatever, mister fossyant?

 

[silva]

View attachment 798474

What is "that", that "esculated"?
I described pluses and minuses of the hollowtech crank+axle system.
That was about it, a description.
The "plus" I experienced of HT2 was a good centering, likely because drivetrain part and axle machined as one piece, resulting in nearly no chain tension variation.
For the rest, the difference compared to my spare other bike, intermittently used (repair>other>back from repair) with square taper setup, was over 10 years a replacement needed, while the square taper not any, also the single other usable bike I have left now.

The broken Stronglight cranks of my current (avatar) bike gave me a chance to try HT2, but dealer said it was not compatible, instead offered Hollow variant / first version Octalink, which proved itself as not solving the chain tension variation, and on top of that, proved its design flaw that results in press-fit left crank working itself loose with as also proven trigger water ingress)
So, when the frame had to be replaced, I saw it as a chance to go back to square taper.

That's all logical non "esculating" behaviour of me, no?
Thanks to all these tryouts, the bike keeps doing the job with 1 chain replacement once in a year, due to eccenter tensioning mechanism at its end of range.
Less work, less cost, that's plus and plus.
There are people that treat their bike (also) as an ornament and a race win thing but to me it's more of getting somewhere with lotsa something.

 

[Drago]

Who's been emasculated?

 

[Vapin' Joe]

and external and thus more exposed bearings, where 1 unit of sand suffices just like a scratch as "death trigger".

How are the bearings more exposed? The only way water or grit can get in is past the seals on the spindle, which are in the same place as on square taper BB's. In fact you could argue they are more secure in that respect because being further outboard they are less in the way of spray from the front tyre.