Sep 28, 2001 5:48 AM
|I understand there are two common BB threads
Italian and English they are both 24 tpi
What is the first number for the BB (on ordering)
68X102 & 73x102
What is the 68 and the 72, are they BB widths ?
And if so how do you know which to get for each frame ?
|That's easy....||Greg Taylor|
Sep 28, 2001 5:54 AM
|The first number is the width of the bottom bracket shell, in millimeters. The second number is the spindle width.
Generally, road bikes use a 68mm bottom bracket. The safest thing to do before ordering a replacement is to either measure the shell, or to just take out the old one and look at the size that is (usually) stamped on the cartridge.
|oh my||Jack S|
Sep 28, 2001 5:59 AM
First # is shell width- 68 is standard English and the one you forgot- 70- is Italian. 73 is oversize English (common on mtn bikes). If you know the shell width you will know whether it is Italian or English. Also, Italian threading is 36mm x 24, English 1.37" x 24. Spindle length depends on crank, frame clearance, and desired chainline.