Faulty Shimano Cranks

Frito Bandito

Zen MBB Master
Oz cycle just posted a video concerning a serious safety issue that you should watch if you have Ultegra 6800, Ultegra R8000, Dura Ace 9000, or Dura Ace R9100 cranks.

 

benphyr

Guru-me-not
Before getting too cranky :D about it we need to realize that all parts have properties.

Currently, manufacturers try to balance the factors for each model and its intended use/user. Factors such as costs (research, development, testing, raw materials, labour, machinery, manufacturing, shipping), safety (quality control, use cycles, wear and tear, safety margins, failure rate, type), longevity, weight, aesthetics, etc. I am sure that there are more factors that I am missing.

We, the consumer, want the best of all worlds but do need to realize that every product we purchase is a mix of all the factors whether they were specifically thought about or not.

When the shimano m600 that was mentioned was developed they were probably not even thinking that two piece bonded cranks were possible or the technology was not yet developed. Now it is available and results in lighter, cheaper product.
 
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Frito Bandito

Zen MBB Master
YW ChaleJake.
Benphyr, I appreciate how they can make bike parts lighter yet stronger. So far it doesn't seem like a recall from Shimano yet and I am not trying to slam Shimano though. I know they make great parts, and I even have a 7000 Shimano 105 groupset on my bike that I am happy with so far. Yeah, I am lucky I went with 105 this time but I got it because it was cheap, not because I thought Ultegra or DA might be subject to failure. Just trying to make sure peeps at least keep an eye on their cranks, and have the chance to warranty them if needed. I am sure the next batches of Shimano will be better after having learned from this.
I am only partly joking that the absolutely gorgeous old school Campagnolo cranks I saw at a local bike shop would look stunning on a V20. If they came with a 55/36 then I would definitely switch ;)
 

benphyr

Guru-me-not
Add to his failure reasons:
Freeze/thaw of moisture and corrosion of salt are much more damaging but only need to be considered by the smaller number of road bikes / riders subjected to these conditions. (If you hang up your road bike at atmospheric conditions where it freezes these could still happen but mostly I am thinking about those of us that ride in them and bring our bikes out from heated buildings into the sub-freezing temperatures. Ie. worst case.

In my opinion he doesn’t clarify which factors influence failure versus which are myths versus what to do about it.

I would guess that most significant failure factors are:
-weight of rider, especially when combined with stiff bike frame. (@ChaleJake this should put aside most of your concerns: weight=low, recumbent avoids standing forces, mbb avoids absolute forces of stiff pedal, crank, frame, weight that diamond frame combine together.
-extreme conditions

Most of us are not going to significantly change either our weight or riding conditions so we should take this as a reminder to do our safety checks and consider what is the best the model for us when our personal situation calls for replacement.
 

benphyr

Guru-me-not
Oh, agreed @Frito Bandito. Thank you for the post and reminder to do the oft neglected safety checks of our bikes.

As a lightish 61kg rider I definitely appreciate any weight savings that has trickled down to my price level of components.
 

Frito Bandito

Zen MBB Master
YW braddah!
61?!?!?! I've got at least an extra 15kg so I really need some weight savings (while I am eating a cup of vanilla ice cream at midnight) and had half a sleeve of Wavy Pringles BBQ after my ride today.
 
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