FAILURE Shimano Cranksets

Discuss light weight issues concerning road bikes & parts.
Post Reply
2lo8
Posts: 539
Joined: Thu Mar 31, 2016 10:32 am

by 2lo8

And NR cranks cracked despite not being hollow because something was done wrong. That’s missing the point.

Old hollow tech was not welding or bonding different pieces together, thus bond failure was not an issue avoiding the issue all together. Just because bond failure is not an issue in a crank doesn’t mean that a crank can’t otherwise be poorly designed, indeed solid cranks can have issues as well. Being bonded doesn’t make a crank immune to design flaws either.

You wouldn’t blame cracking spiders on the sweet wings being welded, so it is curious how you can blame the faults on hollowtech, not only that but those faults have since been fixed in an entirely conventional way that would be used to fix any other crank of any other construction method to deal with stress risers and lack of strength.
[6.6kg of no carbon fiber]
[2lo8.wordpress.com]
Your one-stop source for information and reviews on cheap eBay bike junk.

by Weenie


User avatar
pdlpsher1
Posts: 2425
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

I did a quick Google and actually found many cases of the crank failures. One guy had his failed and then a friend told him that his also failed two weeks prior. Sure does sound like it's more common than people believed....

http://carlinthecyclist.com/epic-failur ... eed-crank/

Image

Image

2lo8
Posts: 539
Joined: Thu Mar 31, 2016 10:32 am

by 2lo8

Also the new cranks are still made from alloy forgings, thus vulnerable to the same faults in addition to bond failures. The cranks being compared aren’t composite and avoid the issues of alloys and forging. It’s not like the bonds are holding and the cranks are tearing along another stress riser, like if you glued two pieces of wood with PU glue, or steel tubes tearing away from brass joints for that matter. Failures are clearly occurring along the bonds.
[6.6kg of no carbon fiber]
[2lo8.wordpress.com]
Your one-stop source for information and reviews on cheap eBay bike junk.

ch00bzs
Posts: 29
Joined: Sat Jun 14, 2014 4:49 pm

by ch00bzs

Hey guys... may i join the club ?


Image

hambini
Posts: 510
Joined: Tue Nov 15, 2016 8:13 am
Location: Cologne, Germany

by hambini

ch00bzs wrote:
Tue May 01, 2018 12:42 pm
Hey guys... may i join the club ?


Image
This looks like it has been dropped on it's side. Strange failure mode
Hambini Aeronautical Engineer, Polluting YouTube since 2016 - views expressed are my own...
Add me ON TWITTER!
Aerodynamic Masterclass in bicycle wheels
I fixed the bottom bracket from hell

User avatar
wheelsONfire
Posts: 3001
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

Strange, i have never seen any Shimano crank that has failed. Are you guys incredibly strong or what makes this?
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

LiquidCooled
Posts: 125
Joined: Mon Oct 02, 2017 5:46 am

by LiquidCooled

hambini wrote:
ch00bzs wrote:
Tue May 01, 2018 12:42 pm
Hey guys... may i join the club ?


Image
This looks like it has been dropped on it's side. Strange failure mode
The scratches/scuff marks just below the crack make it seem like there was a big impact. Perhaps this caused the failure, rather than just pedalling.

Sent from my moto x4 using Tapatalk

2017 Giant TCR Advanced Pro 0 Disc
2003 Cannondale R1000 (CAAD7)

Attermann
Posts: 402
Joined: Sun Jan 05, 2014 11:04 pm
Location: Denmark

by Attermann

That looks just like marks from a shoe

User avatar
kgt
Posts: 7925
Joined: Sun Jun 18, 2006 10:29 am
Location: Athens, Greece

by kgt

It is really strange that more and more of these failures pop up lately...
BTW I could never understand why Shimano insists on alu cranks. Are these much cheaper to produce? A carbon crankset is better in many aspects including strength.

ch00bzs
Posts: 29
Joined: Sat Jun 14, 2014 4:49 pm

by ch00bzs

nope it's just scuff from shoes :)
LiquidCooled wrote:
Tue May 01, 2018 3:17 pm
hambini wrote:
ch00bzs wrote:
Tue May 01, 2018 12:42 pm
Hey guys... may i join the club ?


Image
This looks like it has been dropped on it's side. Strange failure mode
The scratches/scuff marks just below the crack make it seem like there was a big impact. Perhaps this caused the failure, rather than just pedalling.

Sent from my moto x4 using Tapatalk

LiquidCooled
Posts: 125
Joined: Mon Oct 02, 2017 5:46 am

by LiquidCooled

Well, then I guess you're part of the club.
2017 Giant TCR Advanced Pro 0 Disc
2003 Cannondale R1000 (CAAD7)

Vuong05
Posts: 141
Joined: Wed Aug 11, 2010 7:52 am

by Vuong05

Scary why so many are failing. Are all these failures during normal riding? Or was it during a race or steep incline, where huge power was put down? Regardless, it has me thinking twice now about this. I'm sure the failure ratio is minute, given how many of these cranks are out there, but food for thought.
Current Stable. Evo (Storm Trooper) : 5.39kg | Alchemy Eros : Heavy (7.25kg)

User avatar
Kayrehn
Posts: 1300
Joined: Thu Mar 24, 2011 6:06 pm

by Kayrehn

Fellow clubmate had this happen to him in last weekend's race. And seeing all this... I wonder if anyone seen broken sram or campagnolo carbon cranks before? Don't want to derail this thread but just really curious to make some comparisons...

Sent from my SM-G930F using Tapatalk


spdntrxi
Posts: 3256
Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

I've broken an THM M3 crankarm... non-drive side.

XCProMD
Posts: 811
Joined: Sat Jan 26, 2008 10:25 am
Location: Cantabria

by XCProMD

Image

Yet one more in a granfondo today..


Inviato dal mio iPhone utilizzando Tapatalk

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post