Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Why did the orientation of the square taper change from diagonal to parallel?

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Why did the orientation of the square taper change from diagonal to parallel?

Old 02-01-13, 09:59 PM
  #1  
saturnhr
Senior Member
Thread Starter
 
Join Date: Nov 2007
Posts: 227
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Why did the orientation of the square taper change from diagonal to parallel?

Most modern cranks (new bmx cranks) new TA (Carmina) cranks all have their square taper parallel in their cranks, the older types all had it diagonal. Does anybody know why?
Makes it impossible to mix and match.
saturnhr is offline  
Old 02-01-13, 10:16 PM
  #2  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 17,544

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3972 Post(s)
Liked 3,337 Times in 2,022 Posts
Being the cynic I would first think of the need to source from the manufacture that started it (like Schwinn did with it's slightly different dimensional standards way back when). The second thought is a work around to some patent. Third is an engineering thought.

Maybe people smarter then I can chime in. Andy.
Andrew R Stewart is offline  
Old 02-01-13, 11:04 PM
  #3  
Dan Burkhart 
Senior member
 
Dan Burkhart's Avatar
 
Join Date: Oct 2004
Location: Oakville Ontario
Posts: 8,010
Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 911 Post(s)
Liked 539 Times in 316 Posts
Originally Posted by saturnhr
Most modern cranks (new bmx cranks) new TA (Carmina) cranks all have their square taper parallel in their cranks, the older types all had it diagonal. Does anybody know why?
Makes it impossible to mix and match.
I don't know that there has ever been a change. Some mfgs make em diamonds, some make em squares. You're right about one thing though, if you mix a Shimano on one side with a Sram on the other, the cranks won't be 180.




Dan Burkhart is offline  
Old 02-02-13, 12:28 AM
  #4  
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 37,675

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 134 Post(s)
Tagged: 1 Thread(s)
Quoted: 5256 Post(s)
Liked 1,561 Times in 894 Posts
From a design standpoint it doesn't matter on the right crank because there's plenty of meat. But on the left where there's lot's less the orientation can affect the strength and whether it'll crack. Most forged cranks are diamond, but many lower end cranks are square. As pointed out earlier, this isn't so much a matter of a change, as of a design difference of opinion.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 02-02-13, 01:25 AM
  #5  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,349 Times in 856 Posts
just 2 ways to do the task.

Manufacturer discression.. it was their choice, ask them.

Last edited by fietsbob; 02-15-13 at 01:15 AM.
fietsbob is offline  
Old 02-02-13, 04:06 AM
  #6  
saturnhr
Senior Member
Thread Starter
 
Join Date: Nov 2007
Posts: 227
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by FBinNY
Most forged cranks are diamond, but many lower end cranks are square. As pointed out earlier, this isn't so much a matter of a change, as of a design difference of opinion.
all contradicted by TA Specialites: they changed their high end forged crank fom diamond (diagonal) to square (parallel)
Attached Images
File Type: jpg
my6bgu2MVRcrS9wYfsnWKEA.jpg (7.6 KB, 89 views)
File Type: jpg
carmina_black_edition.jpg (100.6 KB, 95 views)

Last edited by saturnhr; 02-02-13 at 04:37 AM. Reason: typo
saturnhr is offline  
Old 02-02-13, 07:42 AM
  #7  
davidad
Senior Member
 
Join Date: Feb 2009
Posts: 6,648
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 574 Post(s)
Liked 168 Times in 136 Posts
Marketing.
davidad is offline  
Old 02-02-13, 08:37 AM
  #8  
HillRider
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656

Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!

Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2025 Post(s)
Likes: 0
Liked 1,085 Times in 733 Posts
Originally Posted by davidad
Marketing.
In what way? I've never seen the difference mentioned in any makers advertising and never seen one way or the other claimed as an advantage?
HillRider is offline  
Old 02-02-13, 09:52 AM
  #9  
vredstein
Senior Member
 
vredstein's Avatar
 
Join Date: Aug 2008
Location: Tucson, Arizona
Posts: 704

Bikes: '02 Lemond Buenos Aires, '98 Fuji Touring w/ Shimano Nexus premium, '06 Jamis Nova 853 cross frame set up as commuter, '03 Fuji Roubaix Pro 853 back up training bike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
I respect the fact that the spindle manufacturers held their ground and stayed with diamonds rather than jumping on the square bandwagon.
vredstein is offline  
Old 02-02-13, 10:17 AM
  #10  
Dan Burkhart 
Senior member
 
Dan Burkhart's Avatar
 
Join Date: Oct 2004
Location: Oakville Ontario
Posts: 8,010
Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 911 Post(s)
Liked 539 Times in 316 Posts
Originally Posted by vredstein
I respect the fact that the spindle manufacturers held their ground and stayed with diamonds rather than jumping on the square bandwagon.
Dan Burkhart is offline  
Old 02-02-13, 10:23 AM
  #11  
Nerull
Senior Member
 
Join Date: May 2010
Location: Madison, WI
Posts: 1,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by saturnhr
all contradicted by TA Specialites: they changed their high end forged crank fom diamond (diagonal) to square (parallel)
I don't think you know what contradiction means.

Some cranks are square, some cranks are diamond. There is no standard and what a manufacturer uses is entirely up to them.

Which part are you having trouble understanding? We'll type it more slowly.
Nerull is offline  
Old 02-02-13, 10:45 AM
  #12  
DOS
Senior Member
 
DOS's Avatar
 
Join Date: Feb 2008
Location: Arlington, VA USA
Posts: 2,107
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 251 Post(s)
Liked 69 Times in 56 Posts
I don't know the answer to the question, but the ability of BF posters to take even the simplest questions and turn them into snarky contentious arguments is a constant source of wonder and entertainment for me. So thanks for that everyone (although I will add that mechanics seem slightly less prone to this, in my observation, than, for example, the roadie forum where threads degrade into gibes and snark pretty much as a matter of course -- quite entertaining) .
DOS is offline  
Old 02-02-13, 01:28 PM
  #13  
MikeWMass
Senior Member
 
Join Date: May 2012
Location: western Massachusetts (greater Springfield area)
Posts: 672

Bikes: Velosolex St. Tropez, LeMond Zurich (spine bike), Rotator swb recumbent

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 53 Post(s)
Likes: 0
Liked 42 Times in 23 Posts
The question nobody has addressed is whether a square crankset can be used on a diamond spindle, or vice versa.
MikeWMass is offline  
Old 02-02-13, 02:30 PM
  #14  
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 37,675

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 134 Post(s)
Tagged: 1 Thread(s)
Quoted: 5256 Post(s)
Liked 1,561 Times in 894 Posts
Originally Posted by MikeWMass
The question nobody has addressed is whether a square crankset can be used on a diamond spindle, or vice versa.
The answer to that is yes, assuming the cranks and spindle are both the same taper - ISO or JIS. Of course you have to replace both cranks at the same time.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 02-02-13, 02:53 PM
  #15  
Road Fan
Senior Member
 
Road Fan's Avatar
 
Join Date: Apr 2005
Location: Ann Arbor, MI
Posts: 16,709

Bikes: 1980 Masi, 1984 Mondonico, 1984 Trek 610, 1980 Woodrup Giro, 2005 Mondonico Futura Leggera ELOS, 1967 PX10E, 1971 Peugeot UO-8

Mentioned: 48 Post(s)
Tagged: 0 Thread(s)
Quoted: 1790 Post(s)
Liked 613 Times in 466 Posts
Originally Posted by MikeWMass
The question nobody has addressed is whether a square crankset can be used on a diamond spindle, or vice versa.
The answer is, nobody can swap out just one. The bike will pedal funny.
Road Fan is online now  
Old 02-02-13, 04:12 PM
  #16  
MikeWMass
Senior Member
 
Join Date: May 2012
Location: western Massachusetts (greater Springfield area)
Posts: 672

Bikes: Velosolex St. Tropez, LeMond Zurich (spine bike), Rotator swb recumbent

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 53 Post(s)
Likes: 0
Liked 42 Times in 23 Posts
(It was supposed to be a joke!)
MikeWMass is offline  
Old 02-02-13, 06:50 PM
  #17  
Dan Burkhart 
Senior member
 
Dan Burkhart's Avatar
 
Join Date: Oct 2004
Location: Oakville Ontario
Posts: 8,010
Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 911 Post(s)
Liked 539 Times in 316 Posts
Originally Posted by MikeWMass
(It was supposed to be a joke!)
Yeah, we got it.
Dan Burkhart is offline  
Old 02-02-13, 06:57 PM
  #18  
kingsting
Bicycle Repairman
 
kingsting's Avatar
 
Join Date: Sep 2010
Location: The Land of Three Mile Island
Posts: 683

Bikes: Many

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Liked 31 Times in 18 Posts
The manufacturers of aftermarket left crank arms have a very powerful lobbying group in DC. They force crank manufacturers to make both styles and alternate years when diamond and square tapers are spec'd on new bikes. That way I have to stock six different left arms (12 if I want to have black and silver. Even more if we want to stock the oddball road sizes) instead of three in my parts bins at the shop. It's all a big conspiracy fueled by dollars from big left crank and their Washington cronies...
kingsting is offline  
Old 02-03-13, 12:11 PM
  #19  
DOS
Senior Member
 
DOS's Avatar
 
Join Date: Feb 2008
Location: Arlington, VA USA
Posts: 2,107
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 251 Post(s)
Liked 69 Times in 56 Posts
Originally Posted by kingsting
The manufacturers of aftermarket left crank arms have a very powerful lobbying group in DC. They force crank manufacturers to make both styles and alternate years when diamond and square tapers are spec'd on new bikes. That way I have to stock six different left arms (12 if I want to have black and silver. Even more if we want to stock the oddball road sizes) instead of three in my parts bins at the shop. It's all a big conspiracy fueled by dollars from big left crank and their Washington cronies...
Thank you
DOS is offline  
Old 02-03-13, 02:02 PM
  #20  
wheelreason
Senior Member
 
Join Date: Aug 2009
Posts: 1,152
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 279 Post(s)
Liked 229 Times in 148 Posts
Originally Posted by kingsting
The manufacturers of aftermarket left crank arms have a very powerful lobbying group in DC. They force crank manufacturers to make both styles and alternate years when diamond and square tapers are spec'd on new bikes. That way I have to stock six different left arms (12 if I want to have black and silver. Even more if we want to stock the oddball road sizes) instead of three in my parts bins at the shop. It's all a big conspiracy fueled by dollars from big left crank and their Washington cronies...
No, its the cranks on the right that are the problem, they defeated the ban on diagonal assault spindles capable of lengths grater than 107, now you can purchase BBs with external bearings without a waiting period...
wheelreason is online now  
Old 02-03-13, 02:17 PM
  #21  
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 37,675

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 134 Post(s)
Tagged: 1 Thread(s)
Quoted: 5256 Post(s)
Liked 1,561 Times in 894 Posts
Originally Posted by wheelreason
No, its the cranks on the right that are the problem, they defeated the ban on diagonal assault spindles capable of lengths grater than 107, now you can purchase BBs with external bearings without a waiting period...
Actually the Congress is split with different parties in control of the House and Senate. They cannot pass a bill mandating either Diamond or Square orientation. This happened before, which lead to a compromise solution in the form of the spline drive system. However with square and diamond cranks grandfathered, the problem remains, so the current proposed solution is to orient the hole so the corner is exactly in between both, or pointing 22.5° off the axis of the crank.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 02-03-13, 05:04 PM
  #22  
ThermionicScott 
working on my sandal tan
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Posts: 22,560

Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)

Mentioned: 98 Post(s)
Tagged: 0 Thread(s)
Quoted: 3850 Post(s)
Liked 2,507 Times in 1,545 Posts
Originally Posted by Dan Burkhart



Just looking at these two examples, it seems that the diamond makes a stronger 5-bolt crank, and the square makes more sense for a 4-bolt crank. A change for either would leave less "meat" at some of the corners.
__________________
Originally Posted by chandltp
There's no such thing as too far.. just lack of time
Originally Posted by noglider
People in this forum are not typical.
RUSA #7498
ThermionicScott is offline  
Old 02-03-13, 06:37 PM
  #23  
Kimmo 
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 9,517

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

Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1513 Post(s)
Liked 707 Times in 501 Posts
Originally Posted by FBinNY
As pointed out earlier, this isn't so much a matter of a change, as of a design difference of opinion.
Doesn't seem like the domain of opinion to me... surely finite element analysis would settle the argument?
Kimmo is offline  
Old 02-03-13, 06:51 PM
  #24  
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 37,675

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 134 Post(s)
Tagged: 1 Thread(s)
Quoted: 5256 Post(s)
Liked 1,561 Times in 894 Posts
Originally Posted by Kimmo
Doesn't seem like the domain of opinion to me... surely finite element analysis would settle the argument?
You're right that for a given crank arm you could calculate the best orientation. However you can change the shape of the crank arm according to how you oriented the hole. Also different materials anf forgings vs. castings may react differently.

So there's no one always correct answer, and either is fine assuming the rest of the design is consistent.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 02-03-13, 06:51 PM
  #25  
loky1179
Senior Member
 
loky1179's Avatar
 
Join Date: Nov 2003
Location: Minneapolis, MN
Posts: 979

Bikes: 2x Bianchi, 2x Specialized, 3x Schwinns

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 98 Post(s)
Liked 9 Times in 5 Posts
Originally Posted by saturnhr
Most modern cranks (new bmx cranks) new TA (Carmina) cranks all have their square taper parallel in their cranks, the older types all had it diagonal. Does anybody know why?
Makes it impossible to mix and match.
Yeah, wish I'd gotten the memo before I ordered the new left arm for my old Suntour crank. A real wtf moment.
loky1179 is offline  

Thread Tools
Search this Thread

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

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.