English bottom bracket history.

Questions about bike hire abroad and everything light bike related. No off-topic chat please

Moderator: Moderator Team

Post Reply
User avatar
Juanmoretime
Administrator
Posts: 7072
Joined: Sat Jun 19, 2004 11:08 am
Location: Urbana, Illinois

by Juanmoretime

I'm curious to see if anyone know how this standard came to be? It seems like pedals the threading should be the opposite direction so that the motion would be in the tightening direction and not the direction that loosens the bottom bracket.
RESIDENT GRUMPY OLD MAN.

by Weenie


mrfish
Posts: 1640
Joined: Wed Mar 28, 2007 12:49 pm
Location: Near Horgen, Switzerland

by mrfish

No, if you think about the forces dragging on the cup, the pedalling forces tighten an English threaded cup. Try riding a slightly loose Italian cup you will find the RHS fixed cup comes undone in minutes. After one experience on an Italian (i.e. normal thread both sides of the frame) you would quickly develop the English standard!

User avatar
stella-azzurra
Posts: 5072
Joined: Mon Jan 23, 2006 6:35 am
Location: New York

by stella-azzurra

I'd rather have the bigger properly torqued Italian cups! :mrgreen:
I never took drugs to improve my performance at any time. I will be willing to stick my finger into a polygraph test if anyone with big media pull wants to take issue. If you buy a signed poster now it will not be tarnished later. --Graeme Obree

monkeyburger
Posts: 116
Joined: Mon Mar 26, 2012 2:45 pm
Location: Bali, Indonesia

by monkeyburger

...finding my inner Onoda-kun...

ZeroG
in the industry
Posts: 156
Joined: Thu Feb 05, 2004 3:53 am
Location: Athens, GA
Contact:

by ZeroG

Left hand threads (counterclockwise to tighten) on the drive-side cups is strange as the friction from pedaling is clockwise which tends to loosen the cups..

User avatar
slyboots
Posts: 445
Joined: Sun May 10, 2009 3:31 pm
Location: Russia, Moscow

by slyboots

ZeroG wrote:friction from pedaling is clockwise which tends to loosen the cups..

It would, if we didn't have bearings inbetween cups and spindle. Luckily we do, so there is not enough friction transferred to overcome static friction between torqued BB cups threads and frame BB threads. As such the other thing we have to deal with is precession (see monkeyburger's post above) which is the reason for English thread standard.

Valbrona
Posts: 1488
Joined: Fri Oct 28, 2011 3:25 am
Location: United Kingdom of Great Britain and Northern Ireland

by Valbrona

monkeyburger knows his stuff.

Its a wonder the Italians have perservered with their sub-standard, standard.

User avatar
elviento
Posts: 1235
Joined: Thu Aug 25, 2005 7:09 pm
Location: In the industry
Contact:

by elviento

In the past, BB cups have nothing pressing them in other than the threads.

With today's crankset designs, this issue seems less relevant.
Fast falcons: http://www.youtube.com/watch?v=j3mTPEuFcWk" onclick="window.open(this.href);return false;
www.falcobike.com
Facebook: falcobikeglobal

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post