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

BB dimensions

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.

BB dimensions

Old 01-01-02, 07:43 AM
  #1  
Junior Member
Thread Starter
 
Join Date: Jan 2002
Location: saipan
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
BB dimensions

So I am planning on replacing my BB and chainrings and now just read the helpful advice re: just buy an entire crankset with rings, it may be cheaper.

So now I wonder if I still must purchase the 118 mm spindle length BB as was the original or do I match the spindle length to the new crankset, which may be different?
samoi is offline  
Old 01-01-02, 10:20 AM
  #2  
Senior Member
 
Join Date: Jul 2000
Posts: 1,049
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Welcome to the Forums! Glad you found us. Hope you'll share more questions and ideas with us. Pics are also a welcome sight. You're the first, that I know of from Saipan.

If you are up-grading your cranks with an expensive pair, then you will have to change spindle length. The Mfgr of the cranks will say which size to use. You will also need to know the BB Shell size --68, 70, 72mm.

However, if you are just replacing them with the same brand, then keep everything as is.
__________________
ljbike
ljbike is offline  
Old 01-01-02, 11:18 AM
  #3  
Mr. Cellophane
 
RainmanP's Avatar
 
Join Date: Nov 2000
Location: New Orleans, LA
Posts: 3,037
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Samoi,
Another thing that can arise with bb is threading - English or Italian. It's easy enough to tell. Italian threading both sides thread in clockwise, ie, "normal". English, one side threads in clockwise, one counterclockwise. Also make sure the crankset and bb you purchase are compatible. Modern Shimano cranks require a modern splined-spindle Shimano bb, and the Shimano mtb spline is apparently different from the road spline. Older "traditional" cranks use a square, tapered spindle. Other than Campagnolo, the tapered square spindle is almost universal, ie, you can mix and match bb and crank brands. Campagnolo is also a square, tapered spindle, but the taper is slightly different so you must use Campy/Campy. For the most part you can mix models with Shimano. For instance, use an Ultegra bb with a 105 or Dura Ace crank. In fact, many recommend using the Ultegra bb with the DA crank because the Ultegra bb is more durable. Forgive me if you already know all this; just trying to help.
Regards,
Raymond
__________________
If it ain't broke, mess with it anyway!
RainmanP is offline  
Old 01-01-02, 02:28 PM
  #4  
Banned
 
Join Date: Aug 2001
Location: upstate New York
Posts: 1,688
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Spindles come in a few 'common' sizes, so it would be best to stick with the length that you currently have (or else your chainline will get screwed up). A few manufacturers offer odd lengths-buy one of these only if a common size is a problem for your application.
__________________
Je vais à vélo, donc je suis!
D*Alex is offline  
Old 01-01-02, 02:53 PM
  #5  
feros ferio
 
John E's Avatar
 
Join Date: Jul 2000
Location: www.ci.encinitas.ca.us
Posts: 21,765

Bikes: 1959 Capo Modell Campagnolo; 1960 Capo Sieger (2); 1962 Carlton Franco Suisse; 1970 Peugeot UO-8; 1982 Bianchi Campione d'Italia; 1988 Schwinn Project KOM-10;

Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 1384 Post(s)
Liked 1,294 Times in 819 Posts
There is one more unwelcome variable here: how deeply the crank seats onto the spindle. I replaced the conventional BB on my son's Specialized Hard Rock mountain bike with a Shimano UN-72, which messed up his chainline because the (Shimano!) cranks did not seat all the way onto the tapers. I salvaged the situation by moving the UN-72 to my aluminum-framed Ross (73mm vs. 68mm BB shell width), and buying a shorter-spindled UN-72 for the Hard Rock.
__________________
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
John E is offline  
Old 01-01-02, 04:44 PM
  #6  
Senior Member
 
pat5319's Avatar
 
Join Date: Sep 2000
Location: Spokane WA
Posts: 1,150

Bikes: Seven Axiom Ti, Trek 620, Masi cylocross (steel). Masi Souleville 8spd, Fat Chance Mtn. (steel), Schwinn Triple Bar cruiser, Mazi Speciale Fix/single, Schwinn Typhoon

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Don't bother with a new crankset, unless it's a signifcant and NEEDED upgrade. Save your money, going that direction is often more expensive.

Ride Well
Pat
pat5319 is offline  
Old 01-02-02, 10:44 AM
  #7  
feros ferio
 
John E's Avatar
 
Join Date: Jul 2000
Location: www.ci.encinitas.ca.us
Posts: 21,765

Bikes: 1959 Capo Modell Campagnolo; 1960 Capo Sieger (2); 1962 Carlton Franco Suisse; 1970 Peugeot UO-8; 1982 Bianchi Campione d'Italia; 1988 Schwinn Project KOM-10;

Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 1384 Post(s)
Liked 1,294 Times in 819 Posts
Originally posted by pat5319
Don't bother with a new crankset, unless it's a signifcant and NEEDED upgrade. ...

Pat
Having broken two cranks while cycling, I don't think a new crankset is always a waste of money.
__________________
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
John E is offline  
Old 01-02-02, 10:55 AM
  #8  
Junior Member
Thread Starter
 
Join Date: Jan 2002
Location: saipan
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
thanks all.

The crankset idea was from a post that explained that it may be cheaper then three new rings, and sure enough there is a deal on an LX hollow crank set for $50 at Jenson's (In the hot deals forum), however these are 9 speed rings and you have to get the BB that matches for another $24, but still good value.

Since I run 7 speed and now understand a bit more about chainline, will stay with the cranks I got and get Nashbar rings.(unless someone tells me quick that they are crap.

Its hard to find 7 speed stuff, which is why the Nashbar rings. I was tempted to take advice that says to just go with 9 speed rings cause they're simply narrower but should still hold the wider chains.

Thanks for the other advice, though I did figger out I have 68 mm English threads and a 118 mm spindle.
samoi is offline  

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.