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

Splined-to-Square-Taper Crank Converter

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.

Splined-to-Square-Taper Crank Converter

Old 11-06-10, 04:29 PM
  #1  
cal_gundert05
My name is Mike, not Cal
Thread Starter
 
Join Date: Jul 2006
Posts: 474
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Splined-to-Square-Taper Crank Converter

I'm not too familiar with splined crankset designs, but this seems like it would allow a splined crankset to be used with a square taper bottom bracket: an anular insert with an exterior that matches the interior of the crank arms, and an interior that matches the taper profile.

Thoughts?
cal_gundert05 is offline  
Old 11-06-10, 04:32 PM
  #2  
simonaway427
Senior Member
 
Join Date: Apr 2010
Location: Fredericton, NB, Canada
Posts: 1,430

Bikes: 2010 S1, 2011 F75X

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
cartridge style BB are so cheap these days, why not just get a BB that matches your crankset?
simonaway427 is offline  
Old 11-06-10, 04:41 PM
  #3  
AEO
Senior Member
 
AEO's Avatar
 
Join Date: Jun 2007
Location: A Coffin Called Earth. or Toronto, ON
Posts: 12,258

Bikes: Bianchi, Miyata, Dahon, Rossin

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 5 Times in 5 Posts
never heard of anything like it.
even if there was such an adaptor, the cranks would sit out very far, giving poor chainline.
__________________
Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
AEO is offline  
Old 11-06-10, 04:46 PM
  #4  
surreal
Senior Member
 
surreal's Avatar
 
Join Date: Mar 2002
Location: NJ
Posts: 3,084
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 5 Times in 4 Posts
i feel very confident that this would be a very bad idea. Not only for the aforementioned chainline issues, but for the worries about the whole thing staying tight and reliable, plus the question must be asked: which isis or octalink crank is worth that kind of silliness?

-rob
surreal is offline  
Old 11-06-10, 05:04 PM
  #5  
cal_gundert05
My name is Mike, not Cal
Thread Starter
 
Join Date: Jul 2006
Posts: 474
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
For the record, I don't need anything like this.

I was just wondering if there would be any technical obstacles; so far, it seems that chainline would be the only one (I don't think that keeping it tightly secured would be any more of an issue than with any other crankset and bottom bracket [as long as there's an inner shoulder to keep the crank arm from sliding inwards]).

Of course, it's also nice to hear from those with more sense than creativity.

Last edited by cal_gundert05; 11-06-10 at 05:04 PM. Reason: TYPO
cal_gundert05 is offline  
Old 11-06-10, 06:08 PM
  #6  
BCRider
Senior Member
 
BCRider's Avatar
 
Join Date: Mar 2008
Location: The 'Wack, BC, Canada
Posts: 5,551

Bikes: Norco (2), Miyata, Canondale, Soma, Redline

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 44 Post(s)
Liked 41 Times in 31 Posts
The cost of such adapters would be at least the same price as a BB to fit the crank arms. What you're after is a rather fancy bit of kit. Also the whole point of a splined crank such as Octalink or ISIS is to reduce the flex in the BB. So why would you WANT to install an adapter that allows you to use a splined crank arm set with a square taper BB?

So basically you've come up with a solution to a question that no one has ever asked or that anyone SHOULD ask. Don't feel bad though. I've done the same thing far more than once...
BCRider is offline  
Old 11-06-10, 06:26 PM
  #7  
MikeWinVA
Senior Member
 
Join Date: Oct 2009
Location: Northern/Central VA
Posts: 212

Bikes: Specialized Sirrus, Univega Activa ST Hybrid, 70's Schwinn Traveler, Giant Innova, Nishiki Mixte

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
That would really screw up the Q factor and chainline. Figure this would make the pedals about 3 inches or more wider apart. Also since it is such an odd shape and small in size it would be a real PIA to machine this out of billet tool steel.

The cost would likely exceed buying a new cartridge bottom bracket as there's no economy of scale on something like this.
MikeWinVA is offline  
Old 11-06-10, 06:28 PM
  #8  
AEO
Senior Member
 
AEO's Avatar
 
Join Date: Jun 2007
Location: A Coffin Called Earth. or Toronto, ON
Posts: 12,258

Bikes: Bianchi, Miyata, Dahon, Rossin

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 5 Times in 5 Posts
the only possible use, I can think of, is for threadless BBs.
__________________
Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
AEO is offline  
Old 11-06-10, 08:26 PM
  #9  
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 1,343 Times in 850 Posts
Echo #2 Just Buy the matching splined BB . ..

[unless you own a manufacturing facility to make what you propose]
fietsbob is offline  
Old 11-06-10, 11:03 PM
  #10  
cal_gundert05
My name is Mike, not Cal
Thread Starter
 
Join Date: Jul 2006
Posts: 474
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
In case it was misunderstood, the entire piece in question would sit within the splined cranks, except for the inside shoulder that I mentioned in my second post. Assuming such a set up is possible, why would the crank arms be moved so far apart (up to 3", by MikeW's estimate)?

Of course, BCRider is right about the practicality and desirability of such an adapter.

However, I will say that this idea came about when thinking about the type of bottom bracket to use in an upcoming build and dreaming of far-off touring: wrestling with the serviceability of cup-and-cone bottom brackets, the availability of cup-and-cone vs cartridge bb's in such places, the disposable nature and increasing prevalence of cartridge units, semi-cartridge bearings like Phil Woods and the matching axles, required tools, etc.
cal_gundert05 is offline  
Old 11-07-10, 10:32 AM
  #11  
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 1,343 Times in 850 Posts
Replacement axles for loose ball bottom brackets are no longer made, and I know of nowhere
that you can get pits reground out of their races, a logical way to reuse old parts,
but no economic support.


for a self supported tour.

square taper seems to still be supplied, the spline schemes were a passing fancy,
and there were never any variety of axle lengths
like there is in square taper..

I have used same crankarms , on 1 bike that needed a 118, and another 127.5, as the tire clearance between the chainstays , and the chainline required.

have you considered a one piece crank? heavy but really durable and all parts are cheap.

back in the 80's there were tubular one piece crankarms, I thought they were quite an elegant piece, all and all.
fietsbob is offline  
Old 11-07-10, 11:04 AM
  #12  
Dan Burkhart 
Senior member
 
Dan Burkhart's Avatar
 
Join Date: Oct 2004
Location: Oakville Ontario
Posts: 7,945
Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 870 Post(s)
Liked 494 Times in 284 Posts
Originally Posted by fietsbob View Post
Replacement axles for loose ball bottom brackets are no longer made.
********************? I have at least 3 sources that still stock them.
Dan Burkhart is offline  
Old 11-07-10, 11:13 AM
  #13  
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 1,343 Times in 850 Posts
name them, Dan.
Ordered thru current Wholesaler or just old dealer stock .. all lengths?

for repairs, 2 kinds .. solid, nut holds on arm, and hollow , bolt threads into it.

Last edited by fietsbob; 11-07-10 at 12:33 PM.
fietsbob is offline  
Old 11-07-10, 12:20 PM
  #14  
Captain Blight
Senior Member
 
Captain Blight's Avatar
 
Join Date: Oct 2009
Location: Minneapolis
Posts: 2,473

Bikes: -1973 Motobecane Mirage -197? Velosolex L'Etoile -'71 Raleigh Super Course

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Quality sells 'em. Happy to ship to your local dealer.

You can also get 'em thru Harris and from Euro-Asia. Sugino and Miche both make 'em, as does Odyssey. They're not common but they are certainly not unavailable.
Captain Blight is offline  
Old 11-07-10, 02:41 PM
  #15  
dobber
Perineal Pressurized
 
dobber's Avatar
 
Join Date: Oct 2003
Location: In Ebritated
Posts: 6,555
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by fietsbob View Post
Replacement axles for loose ball bottom brackets are no longer made, and I know of nowhere
that you can get pits reground out of their races, a logical way to reuse old parts,
but no economic support.
Why even bother? The replacement of a loose ball with a cartridge bottom bracket is way too easy.
__________________
This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.
dobber is offline  
Old 11-07-10, 11:48 PM
  #16  
cal_gundert05
My name is Mike, not Cal
Thread Starter
 
Join Date: Jul 2006
Posts: 474
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
fietsbob, I did consider one-piece cranks; my main objection is that their pedal threads are 1/2", not 9/16".

As for the availability of bottom bracket axles, I would like to build a fixed gear, and I'd need an axle that is shorter than what most cranksets require (although, with modern road or mountain bike frame spacing, I suppose a longer bb axle could be used if you rearrange the spacers and redish the wheel to correct the chainline--not practical, though). I suspect that high end Japanese cup-and-cone bottom brackets and parts will always be around, but they can be kinda pricey, and one is unlikely to find them in most shops.
cal_gundert05 is offline  
Old 11-10-10, 12:16 AM
  #17  
cal_gundert05
My name is Mike, not Cal
Thread Starter
 
Join Date: Jul 2006
Posts: 474
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
As a side note, I just awoke from a late-night nap in which I dreamt that I disassembled my bottom bracket (which looked more like a hub) to find that my bearings had turned to dust. Maybe that's a sign of some sort. In this dream I also saw a prostitute who hangs out on my block sometimes.
cal_gundert05 is offline  
Old 11-10-10, 12:57 PM
  #18  
DannoXYZ 
Senior Member
 
DannoXYZ's Avatar
 
Join Date: Jul 2005
Location: Saratoga, CA
Posts: 11,736
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Liked 7 Times in 5 Posts
What did the you do with the prostitute and your bottom-bracket that turned the bearings to dust???
DannoXYZ is offline  
Old 11-10-10, 06:22 PM
  #19  
cal_gundert05
My name is Mike, not Cal
Thread Starter
 
Join Date: Jul 2006
Posts: 474
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by DannoXYZ View Post
What did the you do with the prostitute...that turned the bearings to dust???
I guess I needed the grease...
cal_gundert05 is offline  
Old 11-10-10, 08:08 PM
  #20  
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 1,343 Times in 850 Posts
I did consider one-piece cranks; my main objection is that their pedal threads are 1/2", not 9/16".
Note: there is a model of SCOR 'knee saver' that is a 1/2'' to 9/16'' pedal adapter,
as it widens the stance a bit also..
fietsbob is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
baldzach
Bicycle Mechanics
1
06-11-16 04:40 PM
The8thSt
Bicycle Mechanics
7
06-01-16 08:05 PM
Essthreetee
Bicycle Mechanics
3
05-30-16 02:29 PM
Myosmith
Bicycle Mechanics
13
04-17-12 06:00 PM
Capecodder
Bicycle Mechanics
14
12-03-10 03:24 PM

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 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.