Miche cranksets considered harmful?

So are we mostly talking about the Advanced Miche cranks with 144 BCD?

Just like @radiobomb73 I had one of the 135BCD Primatos for nearly 2 years on my daily and never had any issues. Have since upgraded and passed the crank along but I believe it's still going on strong.

Is this the crankset you're referring to @M_V

Not sure if there are differences other than graphics but these are the arms that were on all 69 bikes, we now have 2 (I think) bikes running the black version of these.

Chainrings have always been black.

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So you're right, those are the 144BCD Primato Advanced cranks that everyone has been talking about.

Funny, I have them on my bike and always had trouble with unexplainable creaking coming from the right crank when under stress. After trial and error I attributed the problem to the chainring bolts, which is the only thing I've yet to change on account of chainring bolts being a royal pain in the ass. Now I'm wondering whether it's the crank itself...

Interesting points. A fleet of bikes running Miche cranksets sounds like a great job. What do you work at?

I’m mechanic at the velodrome up here in Glasgow.

I'm just gonna put these pics up because the similarity to the other broken cranks is hard to ignore. my main issue in the end was their insistence that I must have been involved in a crash that I wasn't telling them about, which was not the case

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Wowser. Any experience of any other cranksets in the same kind of numbers? 69 unsnapped velodrome cranksets is a lot. At the same time, I haven't been able to find as many individual complaints as we have here or as you can find elsewhere (e.g. Chain Reaction) about, say, Dura Ace or Sugino or whatever.

I had creaking before this happened

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Drive side again, lower down.

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So maybe this is more of a street use vs. velodrome use thing? Like the old Campy sheriff star hubs.

Those failures on the spider look like they can be caused by the bike falling over with the pedal hitting the ground first. This creates a lot of torque in that area. Failure could occur through fatigue or a badly placed notch (or both)

I think my bike has fallen over before onto that side tbh

Here's my Miche Primato Advanced with a crack. At least three others I know have found similar, all noticed it before it snapped. I bought mine secondhand, looked like new, and used for commuting and such for 2-3 years.

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I have a Primato chainset on my fixed bike, and I’m now a bit concerned about it. Has anyone thought about the effect of rider weight? I would have thought that the heavier a rider is, the more likely a failure of this kind. I guess I am trying to avoid fat-shaming accusations and ask politely how heavy are people who have had this crank failure?!

I am quite light (less than 60kg - scrawny weakling comments expected) so I am hoping I will get away with continuing to use these cranks, but I am certainly going to keep a close eye on them. Interested to hear what everyone thinks...

107kg.

Thanks, good to know. Anyone else who has had this crank failure?

I'm 73-75kg. Two of my friends that have had one of those cranks crack are lighter than I am.

Ah ok, maybe I do need to find some Sugino!

Nearly all these pictures show fatigue failures. They had to have occurred over some time, and will have begun with a crack, invariably at a stress raiser - some sharp point in the crank, or a casting/forging error.

Looking at the broken surfaces, you can see where the face is dirty, is where the crack has been developing over weeks/months/years. The two halves fit back together neatly, also. The bright surface is a ductile failure, and shows how little material the component was still hanging on by. It’s surprising the story that these things tell.

The cause of these failures is virtually never rider error, or overload. If you tried to overload a new crank to destruction- by clamping it in a large vise and levering it with a breaker bar, say - it would bend, rather than crack. This persistent line from manufacturers that ‘you did something wrong’ is erroneous and unfair.

Really useful and interesting, thanks. Sounds like a genuine and serious problem with the design and/or manufacture of these cranks.

Sadly, I think the manufacturers themselves- at least their public facing departments- don't understand the causes of these failures either, and thus their blame of the operator is not generally dishonest (though still wrong!).

There used to be a rich collection of similar failures, with insightful commentary, here:

http://pardo.net/bike/pic/fail-012/000.html

It seems to have lost a few pages though. Still, an interesting read.

Edit- ah, here you go:

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

This persistent line from manufacturers that ‘you did something wrong’ is erroneous and unfair.

In this case, probably, but in the bike industry user error is never owned up by the customer, so much so that there's an actual term for it.

So I replaced my Primato cranks yesterday and found the same crack as +Samuli

Shit, I need to get mine off my bike and check them properly.