this can't be common right?

[vqdriver]

any shopowner input is welcome here.

i've been a longtime fan of shimano's hollowtech II cranks but this is diconcerting. just ran across it while reading about the 7900 stuff, tho i suppose any thin walled spindle would run the same risk

http://www.roadgrime.com.au/file/broken_dura_ace_crank_61.jpg

thread here:

http://www.bicycles.net.au/forums/viewtopic.php?f=34&t=40469

[oliver1850]

Very hard to know what caused it.

Could have started with a small nick. I've seen people riding all sorts of stuff with stress risers that will eventually lead to a failure. Like cutting bar tape off against the bar and scoring it right up near the stem where stress is highest. As stuff becomes lighter, being careful with it becomes more important.

If they start turning up all over the place, I'd be more concerned than with one with an unknown history.

[bikinchris]

All spindles can break. I had a solid JIS taper spindle break off right at the place where you put power for a final sprint coming out of a corner. The guys behind me said the sparks from the chainrings hitting the road were pretty cool. I kept it up and didn't crash, but I don't know how, since my chest was on the stem and I nearly hit the front tire with my head.
Anything can break.

[Jeff N.]

Gnarly! Jeff N.

[DRietz]

The cool part, though? Shimano will FOR SURE take care of that for you.

[kramnnim]

http://brokenbikeparts.com/wp-content/uploads/2011/08/Broken-Campagnolo-Super-Record-Ultra-Torque-Crankset-1024x765.jpg

:(

[thirdgenbird]

Is that yours? Any idea what caused the failure?

Edit: noticed the cult bearings, is that titanium or steel?

[mike p]

Every bike part made has broke. Only important when they break in large numbers.

Mike

[kramnnim]

Is that yours? Any idea what caused the failure?

Edit: noticed the cult bearings, is that titanium or steel?

No, not mine...story here- http://forums.roadbikereview.com/campagnolo/campa-super-record-crank-broken-252199.html

[FastVegan]

We should rename this thread; "broken cranks"

http://www.flickr.com/photos/36779852@N03/8035312315/in/set-72157631648843803/

Lightning carbon cranks, broke 10 miles into a 30 mile XC MTB race.

EVERYTHING can break.

[Peter P.]

While everything CAN break, it's the ODDS of it breaking that worry me.

If those hollow spindles are made of aluminum, I'd like to know what their mean time before failure is vs. a steel spindle (not of the same design, but whatever existing designs are available).

The idea of aluminum spindles for a BB axle don't thrill me, but I ASSUME the engineers have designed these things to meet or exceed the durability of steel BB axles ;-)

[572cv]

I have an old Campagnolo NR crank I saved after I sheared the crank arm on a climb. Some little flaw- and it just snapped. I fell over, didn't get hurt and had, for a while, huge cred. on climbing strength. unwarranted, IMO.

[ultraman6970]

That campagnolo one.. hmm... The way it cracked like if it was cracked for a long time before giving up. That shimano crank, the axle is just paper thin, all i can say.

[DRietz]

The bearing on the non drive of the Shimano crank looks seized onto the spindle. Makes me wonder if a defect was aggravated by the weakening effects of corrosion?

[kramnnim]

While everything CAN break, it's the ODDS of it breaking that worry me.

If those hollow spindles are made of aluminum, I'd like to know what their mean time before failure is vs. a steel spindle (not of the same design, but whatever existing designs are available).

The idea of aluminum spindles for a BB axle don't thrill me, but I ASSUME the engineers have designed these things to meet or exceed the durability of steel BB axles ;-)

The DA and SR cranks pictured in the thread both have steel spindles.

[cfox]

These threads are ridiculous. That crank could have been kicked around the floor for an hour by the owners pet chimp before it was installed. Or maybe the owner is a weight weenie and he filed down the spindle a bit. Point is: who knows? There are many reasons why anything can break. But do know this: Shimano tests their products for years under severe conditions none of us will ever encounter. You can't really expect a manufacturer to do more than that.

[ultraman6970]

Personally i never seen a shimano crank to fail ever, i know there are some cases but are way less than campagnolo cranksets. Specially the old ones.

[oldpotatoe]

These threads are ridiculous. That crank could have been kicked around the floor for an hour by the owners pet chimp before it was installed. Or maybe the owner is a weight weenie and he filed down the spindle a bit. Point is: who knows? There are many reasons why anything can break. But do know this: Shimano tests their products for years under severe conditions none of us will ever encounter. You can't really expect a manufacturer to do more than that.

I agree. On the interweb you can find anything about anything(whether it's an actual pic or not) then say it's a problem or issue.

[Charles M]

"This can't be common right?"


Right.