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Bottom Bracket Threading Question.(14 posts)

Bottom Bracket Threading Question.chopper
Nov 22, 2002 2:40 PM
If you are looking at the chain-side of your bottom bracket (right side I believe) and to tighten the BB you turn it clockwise, is this right threaded or left?

Thanks.
re: Bottom Bracket Threading Question.beaten leader
Nov 22, 2002 2:55 PM
A right handed thread turns clockwise, A left handed thread turns counterclockwise.
Threading directionCalvin
Nov 22, 2002 3:00 PM
The common threading for bottom brackets is the ISO/English/BSC, which is a left-hand threading for the drive side. Tighten counter-clockwise (to the left). The non-drive (left side) is a right-hand, tighten clockwise.
A CRESCENT WRENCH???!!!!!Alexx
Nov 22, 2002 4:56 PM
Good god, man-don't you have any decent tools?
yes, a crescent wrenchPeterRider
Nov 23, 2002 6:57 PM
without criticizing or approving, I think this picture is taken from the Park Tool website :-)

Pierre
Adjustable wrenchCalvin
Nov 25, 2002 5:44 AM
This image is from the Park Tool web site repair area. While I would rather everyone use a torque wrench, it is not practical to think everyone has one.
Thanks. So, how is it that the conventional left threadingchopper
Nov 22, 2002 3:30 PM
is self-tightening. This seems counter intuitive since the cranks turn clockwise. I have a right threaded bottom bracket which kept loosening until lock-tite was applied.
Thanks. So, how is it that the conventional left threadingSpoke Wrench
Nov 22, 2002 8:09 PM
There's a bearing between the bb spindle and the bb shell. As you pedal, the bearing, where it touches the bb shell, is going the other way.
Thanks. So, how is it that the conventional left threadingSpunout
Nov 25, 2002 4:53 AM
Imagine a Sun-gear, where a spindle turns inside a gear, inside a shell. The turning spindle(clockwise) actually turns the middle gear (your BB cup) counter-clockwise. So, everything {should} stay tight.
Italian or Swiss threadKerry
Nov 22, 2002 3:35 PM
If you have a right hand threaded right BB cup, it is probably Italian (36mm x 24 TPI), though if it is an old enough bike, it could be Swiss (35mm x 1 threads per mm).
Its actually French and quite normal for this to happenchopper
Nov 22, 2002 3:44 PM
according to Sheldon Brown, it just seems counter-intuitive. The BB is fine now but it certainly is a lesson learned.
Yup, I had Swiss and French reversed (Ha!) - nmKerry
Nov 22, 2002 4:11 PM
re: Bottom Bracket Threading Question.tag
Nov 22, 2002 10:17 PM
To remember the right hand rule, stick out your right hand. If you turn something in the direction of your fingers, and it moves in the direction of your thumb, that is right threaded. Ditto with the left hand. Works on more than threads too.
Sounds like you learned that in Physics.jzinckgra
Nov 25, 2002 12:29 PM
....but probably the only thing i remember. electrostatic direction or something like that