's Forum Archives - Components

Archive Home >> Components(1 2 3 4 5 6 7 8 9 10 )

Upgrading - bottom bracket(7 posts)

Upgrading - bottom bracketcondidit
Aug 15, 2001 5:50 AM
I have an older Condor bike I want to upgrade with some modern stuff. The bottom bracket is the older cup and cone type. Will a modern cartridge bb fit in this frame ?
yes, as long as....alex the engineer
Aug 15, 2001 11:04 AM is of the same TYPE of threading (swiss, french, italian, english, or whitworth). Most "modern stuff" is italian or english. French, swiss, or whitworth will be difficult, although some high $$ manufacturers still do make these sizes.
ok, so how do I..condidit
Aug 15, 2001 12:14 PM
determine what the threading type I have. It is an English bike so I guess it is an English thread. The most common choices for bb are like "68 x 115 English" or "70 x 115 Italian" is there a way to inspect/measure the threads to determine what would works? ie what do the numbers mean?

The numbers...Cima Coppi
Aug 15, 2001 12:42 PM
For bb sizing the first number (68 and 70) are the thread sizes (in threads per inch I believe). The second number is the length of the bb spindle. The only way for you to know what the threads are on your Condor is to remove one of the bb cups and have a shop tell you what it is. To say the threads are English because the frame in English may not be totally accurate. My frame is made in the U.S., but the builder uses Italian threading on the BB shell.

The spindle length is equally as important if you are keeping your cranks. Too short a bb spindle may cause the inner chainring to rub against the chainstay, and too long a bb will cause shifting to be unreliable. Have a shop tell you the necessary info, and go from there.

A bb is easy to install with the correct tools, but beware the drive side fixed cup. It is most likely on very tight, and can be very difficult to loosen.

Good luck,

...and is it Rt. hand or Lft. hand threaded ? nmLeroy L
Aug 15, 2001 12:52 PM
Boy, are you confused!Kerry Irons
Aug 15, 2001 4:11 PM
The 68 and 70 refer to the width of the BB shell, which determines the spacing between the "shoulders" on the BB axle (the cones the bearings ride on). The 115 (or 118, 120, 123, 125, 130, etc.) is the spindle length, and is used to adjust chain line. You have to have the 68/70 match, or your adjustable cup will be too far in/out of the BB. A cartridge BB will fit, as long as you get the right length axle and the right thread. BB threads are as follows:

French & Swiss: 35 mm diameter, 1 thread/mm Swiss fixed cup is right hand thread, French fixed cup is left hand thread.

English: 1.370 inches diameter (pretty close to 35 mm), 24 threads per inch.

Italian: 36 mm diameter, 24 tpi.

Many BB cups have the size stamped in them. Otherwise, time to get out the calipers.
Thanks Kerry nmcondidit
Aug 16, 2001 4:59 AM