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

BB73 and BC-73 thread compatibility

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.

BB73 and BC-73 thread compatibility

Old 07-23-19, 12:44 PM
  #1  
bigalgeorge
Junior Member
Thread Starter
 
Join Date: Jan 2019
Posts: 13
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
BB73 and BC-73 thread compatibility

BC-73 thread same as BB73 thread? I am replacing BB73 68mm 116mm
I ask suppliers in Asia, and they dont know. The BC has same turns on thread and other specs but SheldonBrown gives no information on BC types and doesnt have BB73 either.

Thanks for answers. Al.
bigalgeorge is offline  
Old 07-23-19, 01:15 PM
  #2  
davidad
Senior Member
 
Join Date: Feb 2009
Posts: 6,581
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 544 Post(s)
Liked 150 Times in 121 Posts
VP-BC73 - VP Components
davidad is offline  
Old 07-23-19, 01:48 PM
  #3  
bigalgeorge
Junior Member
Thread Starter
 
Join Date: Jan 2019
Posts: 13
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Yes, I am aware of that but I am not aware if the thread is different or not hence OP
bigalgeorge is offline  
Old 07-23-19, 04:49 PM
  #4  
davidad
Senior Member
 
Join Date: Feb 2009
Posts: 6,581
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 544 Post(s)
Liked 150 Times in 121 Posts
The odds are that the threads are English because of the 68mm width.
davidad is offline  
Old 07-24-19, 10:31 AM
  #5  
Wilfred Laurier
Señor Member
 
Wilfred Laurier's Avatar
 
Join Date: Feb 2013
Posts: 5,063
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 646 Post(s)
Liked 282 Times in 206 Posts
Before all the terrible press-fit BB concepts came along, there were three common BB sizes - English threaded 68mm, English threaded 73mm, and Italian.

The threads on 68mm and 73mm are the same, but you generally need different cups for each size because the BB willnot be centred or properly fastened in place if you use the wrong one. Threaded BBs come in both these sizes to match whatever your frame wants.

Italian threaded BB shells are 70mm wide, and the threads are completely different - in size and even in handedness on the drive side (English is LH thread on the drive side and RH thred on the ND side, Italian is RH thread on both sides.)

However, I don't think any of this matters. I think the BB73 the OP is referring to is just a model name for a particular bottom bracket, as BC73 is in the above link. If you have a 68mm wide threaded BB shell on a modern-ish bike (after ~1980), the bike will work with standard Shimano 68mm bottom brackets. You only need to match the spindle length to get the right one.
Wilfred Laurier is offline  
Old 07-24-19, 10:46 AM
  #6  
Iride01
MotuekaCascadeChinook
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 10,300

Bikes: '20 Tarmac Disc Comp '78 Raleigh Competition GS

Mentioned: 40 Post(s)
Tagged: 0 Thread(s)
Quoted: 4156 Post(s)
Liked 2,685 Times in 1,869 Posts
Why do you say your's is a BB73 then go on to identify it as a 68x116 size?

Don't be so secretive about your bike. Let us know what it is and maybe we won't be so confused about how to answer you.
Iride01 is offline  
Old 07-28-19, 06:49 PM
  #7  
bigalgeorge
Junior Member
Thread Starter
 
Join Date: Jan 2019
Posts: 13
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Iride01 View Post
Don't be so secretive about your bike. Let us know what it is and maybe we won't be so confused about how to answer you.
Its no secret, this forum rules are: You are not allowed to post URLs or IMAGES until you have at least 10 posts
I have likely done this, but still cant post you a picture but anyway, and asking the mediators of forum has given no joy either.

The bike is one of a bunch of Ebikes I got made in China. It came with a graunchy BB.
Pity the picture thing doesnt work as you would see the problem, but after taking out my trusty calipers I figured that China must have had a bad day, because the axle in all my spares BB were the wrong way around. Just 1mm more on axle width one side, but enough to stop the slip-on hall-effect sensor from going on.

Thanks for info regards threads Ive order a VP BB and hopefully it will sort it out.

Maybe one day I will be able to post pictures here but not holding my breath.
Al
bigalgeorge is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
tyler_fred
Classic & Vintage
1
12-19-18 03:29 PM
Homebrew01
Professional Cycling For the Fans
0
05-15-17 06:36 AM
EPICBYTES
Bicycle Mechanics
0
01-14-12 11:34 AM
ModeratedUser150120149
Fifty Plus (50+)
9
02-16-11 12:26 PM
c0urt
Triathlon
1
01-03-10 05:08 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 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.