TD2 vs XD2 breakages.

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LancsGirl
Posts: 255
Joined: 5 Jun 2021, 9:57pm

TD2 vs XD2 breakages.

Post by LancsGirl »

I'm trying to decide between Spa XD2 or TD2 cranks. Then somewhere I read that the XD2 is better because it is less likely to break. I'm not really sure I understand why the TD2 is more prone to breaking, but apparently it's something like this:

http://technology.open.ac.uk/materials/mem/mem_ccf4.htm

Then I found another "bits of bikes that break" site:

http://www.pardo.net/bike/pic/fail-001/000.html

Given that on that second site, the majority of the broken cranks are not at the crank arm/spider arm junction (as per TD2), is the possibility of the TD2 breaking so small that I shouldn't worry? I'm not heavy or powerful, and very rarely stand on the pedals.

Thanks.
Last edited by LancsGirl on 29 Jan 2023, 5:45pm, edited 1 time in total.
NickJP
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Re: Cranks breaking - irrational fear of death?

Post by NickJP »

If you're worried about dying, I'd say you're more likely to get skittled by a car...
axel_knutt
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Re: Cranks breaking - irrational fear of death?

Post by axel_knutt »

Cranks do break, this was after I grounded the pedal on a corner:
Crank Fatigue.JPG
Crank Fatigue.JPG (5.75 KiB) Viewed 1019 times
No bones broken but I was as bruised as I've ever been, and unable to sleep on my right side for several weeks.
“I'm not upset that you lied to me, I'm upset that from now on I can't believe you.”
― Friedrich Nietzsche
Barrowman
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Re: Cranks breaking - irrational fear of death?

Post by Barrowman »

Crank failure is generally caused by an external issue, like grounding the pedal as in Axel Nutts case.
I actually managed to break a bottom bracket axle ( as in the crank and the square came off whilst riding) ( I fear I had overdone tightening the crank bolts ) (no harm done thankfully apart from having to wait for a lift home ) . It's pretty rare in my experience, many miles with the CTC and other clubs . Regular checks ( as in quick look over) will reveal any unusual 'new' cracks . I am sure if there was an inherent fault with the cranks they wouldn't be on sale. But if you have that nagging doubt in your mind might be worth avoiding them.
No experience of that particular crank.
PT1029
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Re: Cranks breaking - irrational fear of death?

Post by PT1029 »

Generally metal breaks after a long period of a crack gradually developing. If worried, clean the cranks regularly and inspect for visible cracks.
Replace when/if cracks are found. You get plenty of time as the cracks grow slowly.
I have seen people unkowingly ride with quite big cracks (think nearly half way through the crank), so good safety margin if you stop using them once a small crack is seen.

Axel Nutt's broken crank fracture looks (mostly) quite dark, so probably been cracked for a while - the crack corroding/tarnishing - and broke when the pedal grounded. The bottom right of the fracture looks much llighter, so probably the last (untarnished) bit that was holding the crank together before the road hit.
alexnharvey
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Re: Cranks breaking - irrational fear of death?

Post by alexnharvey »

Wait until you realise stems, seatposts forks and handlebars all fail as well.
slowster
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Re: Cranks breaking - irrational fear of death?

Post by slowster »

Brucey used those pictures in a few threads (see below), and a key point he made was that the particular design of those cranks with their sharp corners and edges meant that they were much more likely to crack. Modern designs and probably superior manufacturing quality should mean that cranks like the TD2 and XD2 are less likely to crack, despite being cheaper cranks in relative terms than the old Campag racing chainsets. I would not be concerned about the issue for touring use.

viewtopic.php?p=699599#p699599

viewtopic.php?p=1079255#p1079255

viewtopic.php?p=1229472#p1229472

viewtopic.php?t=143417
cycle tramp
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Re: Cranks breaking - irrational fear of death?

Post by cycle tramp »

LancsGirl wrote: 27 Jan 2023, 11:47pm I'm trying to decide between Spa XD2 or TD2 cranks. Then somewhere I read that the XD2 is better because it is less likely to break. I'm not really sure I understand why the TD2 is more prone to breaking, but apparently it's something like this:

http://technology.open.ac.uk/materials/mem/mem_ccf4.htm

Then I found another "bits of bikes that break" site:

http://www.pardo.net/bike/pic/fail-001/000.html

Given that on that second site, the majority of the broken cranks are not at the crank arm/spider arm junction (as per TD2), is the possibility of the TD2 breaking so small that I shouldn't worry? I'm not heavy or powerful, and very rarely stand on the pedals.

Thanks.
PLOT SPOILER ALERT: you will die - it is one of the only certainties in life. However it will not be for many many years, and it will be peaceful and you'll be surrounded by the ones you love.
Although in my case death wasn't for that long and the nice people from the ambulance brought me back. I don't recommend dying, and would try to put it off for as long as possible. Being dead makes it harder to do everything else on your to-do list.

Having got this out of the way, use pedal washers to stop the pedal axles from digging chunks of alloy out of your cranks when you tighten them, spin rather than honk, beware of any creaking noises coming from the bottom bracket, crank area - which may be a sign of a crack forming.. regularly inspect your cranks for and cracks or damage.
Motorhead: god was never on your sidehttps://www.google.com/search?ie=UTF-8&client=m ... +your+side
mattsccm
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Re: Cranks breaking - irrational fear of death?

Post by mattsccm »

I reckon that if the OP can overcome this worry they will find plenty more in cycling. A bust crank is unlikely to kill you whereas a fork is much more likely. Rolling across the road infront of a lorry can happen for many a reason and a bust crank is fairly low down the risk scale.
LancsGirl
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Re: Cranks breaking - irrational fear of death?

Post by LancsGirl »

alexnharvey wrote: 28 Jan 2023, 11:54am Wait until you realise stems, seatposts forks and handlebars all fail as well.
Wait, what?!? That's it, I'm never stepping foot outside the house again. Mind you, there's gas and electricity and sharp knives and stairs and.... oh god, it's just hopeless isn't it?

Seriously now, yes, I'm aware those things break too. Though in an attempt to lower risk (by reducing aluminium components) I did invest in a steel Nitto S84 seatpost recently:

https://freshtripe.co.uk/nitto-s84-lugged-seatpost/

Which is the most beautiful thing I've ever held in my hands. Well, there was that guy in Hamburg, but that's another story.

The various pictures of broken aluminium seatposts are disturbing, to say the least.

The frame, including forks, is high quality (I'm told) steel. I may sometime change the stem to steel, Nitto make one of those too apparently. And I log miles, so I'll change bars every so often.
LancsGirl
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Re: Cranks breaking - irrational fear of death?

Post by LancsGirl »

cycle tramp wrote: 28 Jan 2023, 12:24pm
LancsGirl wrote: 27 Jan 2023, 11:47pm I'm trying to decide between Spa XD2 or TD2 cranks. Then somewhere I read that the XD2 is better because it is less likely to break. I'm not really sure I understand why the TD2 is more prone to breaking, but apparently it's something like this:

http://technology.open.ac.uk/materials/mem/mem_ccf4.htm

Then I found another "bits of bikes that break" site:

http://www.pardo.net/bike/pic/fail-001/000.html

Given that on that second site, the majority of the broken cranks are not at the crank arm/spider arm junction (as per TD2), is the possibility of the TD2 breaking so small that I shouldn't worry? I'm not heavy or powerful, and very rarely stand on the pedals.

Thanks.
PLOT SPOILER ALERT: you will die - it is one of the only certainties in life. However it will not be for many many years, and it will be peaceful and you'll be surrounded by the ones you love.
I hope to die like my father, peacefully in his sleep. Not screaming in terror like his passengers. (yes, I know it's an old one, but it's still good).
cycle tramp wrote: 28 Jan 2023, 12:24pm Having got this out of the way, use pedal washers to stop the pedal axles from digging chunks of alloy out of your cranks when you tighten them, spin rather than honk, beware of any creaking noises coming from the bottom bracket, crank area - which may be a sign of a crack forming.. regularly inspect your cranks for and cracks or damage.
Yes, I plan to install pedal washers soon. I didn't know they were a thing until I saw that list of "1000 ways your cranks might fail", many of which do seem to be at the pedal hole.

And yes, I'm aware of any noises, and do a bit of work investigating and eliminating them - mudguard rattle, creaky saddle etc. All the better to hear other noises that might be a sign of my imminent demise.
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gazza_d
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Re: Cranks breaking - irrational fear of death?

Post by gazza_d »

I've never broken a crankset. Well apart from stripping a pedal thread but I didn't even fall off then.

I have however broken three sets of handlebars in the 40 years I've been cycling. I'm not dead yet.
I think the Spa cranksets are sourced from Sugino. I'd trust them..
axel_knutt
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Re: Cranks breaking - irrational fear of death?

Post by axel_knutt »

Barrowman wrote: 28 Jan 2023, 8:23amRegular checks ( as in quick look over) will reveal any unusual 'new' cracks . I am sure if there was an inherent fault with the cranks they wouldn't be on sale. But if you have that nagging doubt in your mind might be worth avoiding them.
No experience of that particular crank.
It's 30 odd years ago now, so I don't recall the time span. First the pedal spindle, then the crank went in fairly short order, but as the penny didn't drop until the crank failed as well, I don't think I'd have been looking for cracks when I replaced the pedal.
mattsccm wrote: 28 Jan 2023, 1:13pm I reckon that if the OP can overcome this worry they will find plenty more in cycling. A bust crank is unlikely to kill you whereas a fork is much more likely. Rolling across the road infront of a lorry can happen for many a reason and a bust crank is fairly low down the risk scale.
If you're standing your full bodyweight on the pedal when a crank fails (when else would it go), you're on the floor before you even know what's happened. The pedal doesn't even have to break off, the same happens if a freewheel ratchet lets go.
“I'm not upset that you lied to me, I'm upset that from now on I can't believe you.”
― Friedrich Nietzsche
rogerzilla
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Re: Cranks breaking - irrational fear of death?

Post by rogerzilla »

I've seen a crank break (pedal eye end) and the rider didn't die.

They will generally go when climbing at a low speed, because that's when the torque is highest.

Pedal washers seem like a good idea but they don't really work. The washer eats into the crank rather than the pedal eating into the crank. Ideally the pedal would have a conical or spherical seat, like a car wheel nut, but no-one wants to change the 9/16" standard and it doesn't really cause enough of a problem to bother.
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531colin
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Re: Cranks breaking - irrational fear of death?

Post by 531colin »

I suggest its completely irrational to worry about things like crank failure......instead, go for a nice calming bike ride.

The only failure which is sufficiently common to plan for is the humble puncture.....carry a spare tube, or two if you like.

Apart from punctures, what else goes wrong? You might ding a rim on a big pothole, or a spoke might fail with fatigue. I think both of those have happened to me in about the last 40 years.

I reckon you are much more likely to get hurt being brought off by ice, gravel, or poor roads in general, loose dogs and bad drivers.
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