john
And some of us are still smart enough to keep with square taper.
The ISIS design, if i remember correctly, was designed by committee*. They got so excited with the splines (which are way overdesigned anyway), they forgot about the bearings.
The octalink design is better because at least the balls run directly on the outer shell and the spindle, so although they are getting close to being marginal capacity wise, at least the two "bearings" aren't mis-aligned !
Another issue with all the non square taper designs is that there no flexibility on "q factor" and I simply don't like riding Bow legged... keeping the legs in closer helps on aerodynamics..
So in my humble opinion, lower friction bearings, possible better aerodynamics, and lifetime durability(phil wood..) greatly outweigh a stiffness increase and weight savings..
What they should really do is make the bb shell bigger. Ok some have, but i don't think that will become standard...
*"I don't believe a committee can write a book. It can, oh, govern a country, perhaps, but I don't believe it can write a book. " Arnold J. Toynbee (or design... )
Ron and Dorothy Strasser wrote:
I am not sold on the exo bearings in dirty conditons, but bet George is right that the top of the line quality is the way to go with regard best operation. Better quality bearings and seals could make a world of difference. I just do not like that sound of grinding when debris gets between the crank arm and bearing face. It does not seem like the result is very positive for the hardware. I was talking to Carl Gurney (rides MTB single speeds) and he is sold on the exo bearings because he has destroyed so many ISIS bbs. Steve Basden said the same thing about ISIS. I tend to believe one could destroy about anything riding MTB single speeds. They are a true test of stresses on the bike. I have had one ISIS go belly up and it was in my Karate Monkey that I abused for about 3.5 years before it died. I am a light rider (130 lbs) so the ISIS is plenty stiff for my needs... even on my single speed. I had one other person tell me they thought the Shimano Octilink was
better because the bearings were larger than the ones in ISIS. I am satisfied with my ISIS and Octilink and will give my rebuilt (phil wood) exo's another fair shot at Cross. You know they (exo) must work just fine in rough conditons as all the top riders are using them...right? Or do they just have team mechanics that totally keep the bikes in tip-top shape after every race or even partial race. George/Evan... who does the work on your bikes....you right?
Lets just ride them bikes.
ron
----- Original Message -----
From: gschreckchat@comcast.net
To: Evan MacKenzie ; obra@list.obra.org
Sent: Tuesday, April 24, 2007 8:11 AM
Subject: Re: [OBRA Chat] External BBs
Although they are expensive, I think you will find that the ceramic bearings will last a long time. Enduro sells kits to retrofit existing BB's so you do not have to buy the ridiculously expensive FSA ceramic bearings.
I think ISIS was better, but Shimano did not seem to be willing to accept a common standard that it did not develop, so we get outbouard bearings. Even FSA says ISIS is better but was forced to offer Mega Exo to compete with Shimano.
--
George Schreck
gschreckchat@comcast.net
(503) 502-0425
-------------- Original message --------------
From: "Evan MacKenzie"
st1\:* { BEHAVIOR: url(#default#ieooui) } My experience with external BBs has so far been very negative, almost to the point that I think the next bike or crank I buy I?ll go back to ISIS. Even if you can get the bearings to spin freely you?ll be lucky to get six months out of them on a cyclocross or mountain bike. At least on the road they stay dry (mostly) and should last a little longer. I never had that problem with internal BBs.
Evan MacKenzie
Urban Planner I
City of Hillsboro
150 E. Main Street, 4th floor
Hillsboro, OR 97123
503-681-6154
evanm@ci.hillsboro.or.us
http://www.ci.hillsboro.or.us/Planning_Department/
Try Hillsboro Maps!
Tons of info on any (addressed) property in Hillsboro
http://hillsboromaps.ci.hillsboro.or.us/hillsboro/index.cfm
------------- __o
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----------(_)/ (_)______Get on your bikes and ride!
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john m schmidt
portland oregon