Snapped spindle

[Dadam]

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

Indeed, it might cause the stainless steel to stain.

 

[Dogtrousers]

, cheapo and more robust/sealed>reliable square taper had stayed the mass' norm, and allow DIY (just a crank puller as special tool),

I don't have any opinion on the other aspects of Hollowtech but it's just as DIY friendly as square taper. Maybe even a little easier. And like square taper requires only one special tool.

I speak as a completely cack handed home mechanic who is allergic to complicated jobs. I've replaced cranksets with outboard BBs (both SRAM Apex and Shimano 105) with little fuss. And square taper too (cartridge and loose bearings).

 

[silva]

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.

Hollowtech 2 has its bearings external - left and right OUTside the bottom bracket, so not protected by it, more exposed to dirt and water, whereas in the simple and durable square taper case, they sit INside. I'm sure you know so why ask?
This is even regardless seals. The bearings have additional protection.

You claim here "outboard" as less in the way of front wheel spray, but that's even when riding straight a cone that is wide enough to reach the chain, again further than the external bearings.
Also, rain dripping from the riders coat drips on the bottom bracket location, in case external bearings outside the enclosure.

 

[Dogtrousers]

Hollowtech 2 has its bearings external - left and right OUTside the bottom bracket, so not protected by it, more exposed to dirt and water, whereas in the simple and durable square taper case, they sit INside. I'm sure you know so why ask?
This is even regardless seals. The bearings have additional protection.

I don't understand that. Ingress to the bearings is only via the seals(or, theoretically, down the seat tube I suppose). Surely it doesn't matter if they are internal or external. If the seals are good, they are protected. If they aren't, they aren't.

 

[silva]

I don't have any opinion on the other aspects of Hollowtech but it's just as DIY friendly as square taper. Maybe even a little easier. And like square taper requires only one special tool.

I speak as a completely cack handed home mechanic who is allergic to complicated jobs. I've replaced cranksets with outboard BBs (both SRAM Apex and Shimano 105) with little fuss. And square taper too (cartridge and loose bearings).

Also about this specific: a crank puller does the job on any square taper, regardless brand and its model, unlike the hollow axle market.

 

[silva]

I don't understand that. Ingress to the bearings is only via the seals(or, theoretically, down the seat tube I suppose). Surely it doesn't matter if they are internal or external. If the seals are good, they are protected. If they aren't, they aren't.

You flag seals as "good" or "not good", with nothing inbetween, as in a digital binary fashion, but seals are degraded by contaminants and wear, and their lifetime shrinks with more of it, requiring more disassembly, replacements, that is. work and cost.
Ingress to bearings is just what follows up ingress to sealings so why threating both separately?

I didn't say water flowing down the seat tube, I said water flowing down the raincoat of the rider, wherever that hangs over, and bearings (or their sealings...) at the sides of the bottom bracket instead of inside it, receive a nice constant douche.

 

[classic33]

You flag seals as "good" or "not good", with nothing inbetween, as in a digital binary fashion, but seals are degraded by contaminants and wear, and their lifetime shrinks with more of it, requiring more disassembly, replacements, that is. work and cost.
Ingress to bearings is just what follows up ingress to sealings so why threating both separately?

I didn't say water flowing down the seat tube, I said water flowing down the raincoat of the rider, wherever that hangs over, and bearings (or their sealings...) at the sides of the bottom bracket instead of inside it, receive a nice constant douche.

He would have been replying to your unedited post, you realise that?

 

[roubaixtuesday]

Also about this specific: a crank puller does the job on any square taper, regardless brand and its model, unlike the hollow axle market.

Not sure what you're getting at here; all you need to remove a hollow tech crank is an Allen key.

Changing the bearings you need a special tool (though as I discovered yesterday, due to not being able to access the drive side, mole grips work just fine).

Personally I do actually favour square taper, as the rings are much cheaper and more readily available too, plus the bearings seem to last much longer. But Hollowtech are much easier to change, I think.

 

[wafter]

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?

Indeed.. the only factor governing the ID appears to be how thin Shimano think they can go on the wall thickness to save mass; which of course is a large selling point of the design.

Safety critical parts like this shouldn't "just fail" in normal use without some exacerbating factor like mechanical damage or corrosion.

Personally I'd take the penelty of a few extra grams for a thicker wall if it removed the possibility of breakages like this.

 

[roubaixtuesday]

Indeed.. the only factor governing the ID appears to be how thin Shimano think they can go on the wall thickness to save mass; which of course is a large selling point of the design.

Safety critical parts like this shouldn't "just fail" in normal use without some exacerbating factor like mechanical damage or corrosion.

Personally I'd take the penelty of a few extra grams for a thicker wall if it removed the possibility of breakages like this.

Are Hollowtech cranksets more or less likely to fail than square taper?

I've had one of each now in my personal experience.

Maybe Hollowtech are *less* prone to sudden failure?

 

[Yellow Saddle]

Dont feed the animals people. Don't, they will just come back again and again.

 

[Yellow Saddle]

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.


View attachment 798388

Once again, a lovely photo that perfectly illustrates the spiral failure of a torque tube. And to think, all that just from left leg power. A failure of true beauty. Engineer's porn.

 

[Webbo2]

The old square taper B/B had those notched lock rings which required a special tool that tended to slip off and damage the paint work round your B/B. I think it required one of those double pin tools to screw the cups in, another sh!t design.

 

[fossyant]

Dont feed the animals people. Don't, they will just come back again and again.

Stuff breaks sometimes, stuff wears out. I just replace worn bits. I have all BB standards in my house. Only SRAM GXP needs bearing replacement a bit more often, but that bike, when used, does get subjected to filth and a battering beyond what the others get.

 

[Ming the Merciless]

Also about this specific: a crank puller does the job on any square taper, regardless brand and its model, unlike the hollow axle market.

I use an Allen key to remove Hollowtech 2. The Allen key works on any Allen bolt of the correct diameter. In fact I can use the same Allen key on other parts of my bike.