Go Back  Bike Forums > Bike Forums > Road Cycling
Reload this Page >

Shimano Hollowtech Crank Install - How to confirm 180 degree install

Notices
Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Shimano Hollowtech Crank Install - How to confirm 180 degree install

Old 05-04-21, 11:01 AM
  #1  
kosmo886
Senior Member
Thread Starter
 
Join Date: Mar 2010
Posts: 186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 146 Post(s)
Likes: 0
Liked 7 Times in 6 Posts
Shimano Hollowtech Crank Install - How to confirm 180 degree install

I am simply replacing a left crank arm with a power meter crank arm and wondering how to confirm a perfect 180 degree install between the left and right arms. I might be over analyzing this, but after install it seems the cranks may be a few degrees off from 180 degree...it could also be an optical illusion given no part is perfectly straight anyways. Is it event possible to be this close to 180, but not spot on?
kosmo886 is offline  
Old 05-04-21, 11:08 AM
  #2  
datlas 
Beyond Bogus
 
datlas's Avatar
 
Join Date: Dec 2007
Location: Malvern, PA (20 miles West of Philly)
Posts: 34,995

Bikes: 1986 Alpine (steel road bike), 2009 Ti Habenero, 2013 Specialized Roubaix

Mentioned: 491 Post(s)
Tagged: 2 Thread(s)
Quoted: 14755 Post(s)
Liked 3,004 Times in 1,529 Posts
Originally Posted by kosmo886 View Post
I am simply replacing a left crank arm with a power meter crank arm and wondering how to confirm a perfect 180 degree install between the left and right arms. I might be over analyzing this, but after install it seems the cranks may be a few degrees off from 180 degree...it could also be an optical illusion given no part is perfectly straight anyways. Is it event possible to be this close to 180, but not spot on?
The splines on the BB spindle don't really permit you to get "close" to 180 degrees, and I have never had a problem with this. You could rotate it one spline/notch in each direction to confirm it's right.

edit: it's been awhile since I installed mine, but I think the little "safety plate" can only hook onto the spindle if the crankarm is in the correct position.
__________________
Originally Posted by rjones28 View Post
Addiction is all about class.

Last edited by datlas; 05-04-21 at 11:35 AM.
datlas is offline  
Likes For datlas:
Old 05-04-21, 12:17 PM
  #3  
Badger6
Obsessed with Eddington
 
Badger6's Avatar
 
Join Date: Jun 2013
Location: Brussels (BE) 🇧🇪
Posts: 634

Bikes: '15 Spesh Diverge, '14 Spesh Fatboy, '18 Spesh Epic, '18 Spesh SL6, '21 Spesh SL7, '21 Spesh Diverge...and maybe n+1?

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 212 Post(s)
Liked 204 Times in 142 Posts
Originally Posted by datlas View Post
The splines on the BB spindle don't really permit you to get "close" to 180 degrees, and I have never had a problem with this. You could rotate it one spline/notch in each direction to confirm it's right.
You cannot install the non-drive side (left) crank arm incorrectly. The splines are keyed, meaning they are not equally sized and spaced, to ensure that the left arm can only be installed onto the spindle at 180° from the drive-side crank arm.
Badger6 is offline  
Old 05-04-21, 09:52 PM
  #4  
smashndash
Senior Member
 
Join Date: Feb 2018
Posts: 1,207

Bikes: 2017 Specialized Allez Sprint Comp

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 724 Post(s)
Liked 256 Times in 180 Posts
Above two are right of course. Nothing more to be said about this topic specifically.

But I'd like to say that this is a FANTASTIC example of how good design improves lives with almost no drawbacks. Shimano could *easily* have chosen to design a splined interface that's radially symmetrical and thus requires careful installation to align. And then if you screwed up the install, Shimano could blame you, the user, for not following their instructions or whatever.

Remember this next time a company tries to blame the user.
smashndash is offline  
Likes For smashndash:
Old 05-04-21, 11:28 PM
  #5  
AdkMtnMonster
Airplanes, bikes, beer.
 
Join Date: Jan 2020
Location: Off the front
Posts: 613

Bikes: Canyon Endurace CF SL 8.0 current favorite, newest bike.

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 319 Post(s)
Liked 598 Times in 270 Posts
Poka-yoke.
AdkMtnMonster is offline  
Old 05-05-21, 03:51 AM
  #6  
kosmo886
Senior Member
Thread Starter
 
Join Date: Mar 2010
Posts: 186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 146 Post(s)
Likes: 0
Liked 7 Times in 6 Posts
Originally Posted by smashndash View Post
Above two are right of course. Nothing more to be said about this topic specifically.

But I'd like to say that this is a FANTASTIC example of how good design improves lives with almost no drawbacks. Shimano could *easily* have chosen to design a splined interface that's radially symmetrical and thus requires careful installation to align. And then if you screwed up the install, Shimano could blame you, the user, for not following their instructions or whatever.

Remember this next time a company tries to blame the user.
I'd agree with this. And the reason I asked the question is when I was new to biking, installing my first crank, I didn't even think about positioning (I guess assuming you shouldn't be apply to install in the wrong position)...I tightened the bolt and the crank positioning was all messed up. Makes much more sense to do it this way!
kosmo886 is offline  
Old 05-05-21, 04:12 AM
  #7  
znomit
Zoom zoom zoom zoom bonk
 
znomit's Avatar
 
Join Date: Sep 2006
Location: New Zealand
Posts: 4,287

Bikes: Giant Defy, Trek 1.7c, BMC GF02, Fuji Tahoe, Scott Sub 35

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 401 Post(s)
Liked 449 Times in 226 Posts
You guys have all read the studies that prove that crank arms 180 degrees apart delivers maximum performance from a bike? Yeah, nah. You probably still use round chainrings too.
znomit is offline  
Likes For znomit:
Old 05-05-21, 06:00 AM
  #8  
Kimmo 
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 9,094

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1148 Post(s)
Liked 419 Times in 303 Posts
Originally Posted by Badger6 View Post
You cannot install the non-drive side (left) crank arm incorrectly. The splines are keyed, meaning they are not equally sized and spaced, to ensure that the left arm can only be installed onto the spindle at 180° from the drive-side crank arm.
Well actually... You can totally install it at 0 degrees if you like, and folks who pedal with their arms do. It'd be nice if Shimano would put another hole for the check pin for these peeps...
Kimmo is offline  
Old 05-05-21, 06:55 AM
  #9  
Badger6
Obsessed with Eddington
 
Badger6's Avatar
 
Join Date: Jun 2013
Location: Brussels (BE) 🇧🇪
Posts: 634

Bikes: '15 Spesh Diverge, '14 Spesh Fatboy, '18 Spesh Epic, '18 Spesh SL6, '21 Spesh SL7, '21 Spesh Diverge...and maybe n+1?

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 212 Post(s)
Liked 204 Times in 142 Posts
Originally Posted by Kimmo View Post
Well actually... You can totally install it at 0 degrees if you like, and folks who pedal with their arms do. It'd be nice if Shimano would put another hole for the check pin for these peeps...
Interesting...

Though, I admit, I've never tried to do this...but, now you've got me curious.
Badger6 is offline  
Old 05-05-21, 09:17 AM
  #10  
eduskator
Senior Member
 
eduskator's Avatar
 
Join Date: Aug 2019
Location: Québec, Canada
Posts: 1,001

Bikes: TCR Pro 0 / Revolt 2

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 440 Post(s)
Liked 254 Times in 192 Posts
You can't install it incorrectly unless you hammer it in. The safety pin won't go in if the left arm is not slid into the spindle correctly.
eduskator is offline  
Old 05-05-21, 02:57 PM
  #11  
Symox
Senior Member
 
Join Date: Jul 2020
Posts: 295

Bikes: '07 Specialized Roubaix Comp Triple, '12 Gravity Fixie, '21 Liv Rove 4, '06? Giant EB Spirit

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 138 Post(s)
Liked 57 Times in 44 Posts
agreed that Shimano was smart in keying the crank arm just like its cassettes/freewheels
Saved countless hours of aggravation by garage mechanics like myself.
Symox is offline  
Old 05-05-21, 03:29 PM
  #12  
Badger6
Obsessed with Eddington
 
Badger6's Avatar
 
Join Date: Jun 2013
Location: Brussels (BE) 🇧🇪
Posts: 634

Bikes: '15 Spesh Diverge, '14 Spesh Fatboy, '18 Spesh Epic, '18 Spesh SL6, '21 Spesh SL7, '21 Spesh Diverge...and maybe n+1?

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 212 Post(s)
Liked 204 Times in 142 Posts
The keying isn't what ensures you can't do it wrong, it's the splines.
Badger6 is offline  
Old 05-05-21, 06:51 PM
  #13  
Kimmo 
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 9,094

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1148 Post(s)
Liked 419 Times in 303 Posts
Originally Posted by Badger6 View Post
Interesting...

Though, I admit, I've never tried to do this...but, now you've got me curious.
Any HT2 cranksets I have lying around off a bike are stored at 0 degrees, they take up a lot less space!
Kimmo is offline  
Likes For Kimmo:
Old 05-05-21, 08:06 PM
  #14  
cxwrench
Senior Member
 
cxwrench's Avatar
 
Join Date: Jul 2013
Location: Nor-Cal
Posts: 1,628

Bikes: lots

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 710 Post(s)
Liked 852 Times in 487 Posts
Besides the stopper plate and it's pin needing to in the hole in the crank axle how hard is it to just look at the damn things and know instantly?
cxwrench is offline  
Likes For cxwrench:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.