Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

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.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 01-19-06, 05:49 AM   #1
Guy Yinon
Senior Member
Thread Starter
 
Join Date: Jan 2005
Bikes:
Posts: 107
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Bottom Bracket Question

Is it possible to install a BB spindle that is appropriate for 73mm BB shell in a bike that has a 68mm BB shell ?
What affect will it have on the drive train ?
Guy Yinon is offline   Reply With Quote
Old 01-19-06, 06:44 AM   #2
capwater
Senior Member
 
capwater's Avatar
 
Join Date: Dec 2004
Location: Quahog, RI
Bikes: Giant TCR Comps, Cdale R5000, Klein Q-Pro, Litespeed Siena, Piasano 105, Redline Conquest Pro, Voodoo Bizango, Fuji Aloha
Posts: 1,509
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
There may be some type of adapter out there, but what's the point? Just so you can use a BB you have laying around? They ain't all that expensive, so pony up for the right one. Most likely if there was some type of adapter it would cost more than getting the right BB. As far as it affecting the chain line, so long as this theoretical adapter centered the spindle it shouldn't matter. Don't McGuyver it, use the proper part.
capwater is offline   Reply With Quote
Old 01-19-06, 06:44 AM   #3
TallRider
Senior Member
 
TallRider's Avatar
 
Join Date: Oct 2005
Location: Fresno, CA
Bikes:
Posts: 4,118
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
I think the spindles are the same; the only difference is the bearing cups are diff sizes. But I may be wrong; I've only worked with English-threaded (68mm) traditional-style bottom brackets.
TallRider is offline   Reply With Quote
Old 01-19-06, 07:01 AM   #4
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Posts: 29,112
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 175 Post(s)
The threading is identical but if you install the drive side (usually the cartridge) all the way in, the non-drive side cup won't screw all the way in as it will bottom on the cartridge before it seats against the bb shell.

I supose you could add 5 mm of spacers under the nds cup. Some Shimano bb's are made to fit either width so the spacers must be available.
HillRider is offline   Reply With Quote
Old 01-19-06, 02:17 PM   #5
pecos
Senior Member
 
Join Date: Aug 2005
Location: Southwest TN
Bikes: Specialized Tarmac S-Works
Posts: 188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by HillRider
The threading is identical but if you install the drive side (usually the cartridge) all the way in, the non-drive side cup won't screw all the way in as it will bottom on the cartridge before it seats against the bb shell.
And that would screw up the Q-factor, right? if so, that should be reason enough not to do it.
pecos is offline   Reply With Quote
Old 01-19-06, 05:47 PM   #6
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Posts: 29,112
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 175 Post(s)
Quote:
Originally Posted by pecos
And that would screw up the Q-factor, right? if so, that should be reason enough not to do it.
No, it wouldn't screw up the Q-factor but it would offset the spindle a bit toward the NDS side and maybe bother the symmetry.
HillRider is offline   Reply With Quote
Old 01-21-06, 09:22 AM   #7
John E
feros ferio
 
John E's Avatar
 
Join Date: Jul 2000
Location: www.ci.encinitas.ca.us
Bikes: 1959 Capo; 1980 Peugeot PKN-10; 1981 Bianchi; 1988 Schwinn KOM-10;
Posts: 17,300
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 135 Post(s)
To maintain a good chainline, you may want to pull the fixed cup and slip on a 2.5mm spacer, which you might be able to scrounge from a freewheel application. Similarly, one can accommodate an Italian spindle in an ISO/English BB by using a 1mm spacer under the fixed cup's flange.
__________________
"Early to bed, early to rise. Work like hell, and advertise." -- George Stahlman
Capo [dschaw'-poe]: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger, S/N 42624
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1981 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
John E is offline   Reply With Quote
Old 01-21-06, 10:50 AM   #8
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Bikes: Catrike 559 I own some others but they don't get ridden very much.
Posts: 26,903
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 206 Post(s)
You can stick a 2mm spacer under each cup and come pretty close. If you have to buy the spacers the right bottom bracket will be easier to find and will probably only cost about $15.00 or $20.00 more. You never have to apologize for doing the job right.
Retro Grouch is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 08:39 AM.