I have heard that ISIS doesn't have the same tendency to 'creak'. But I think I got that info from the ST forum, so go figure.....

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"And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country" JFK - Replace 'country' with the company you work for, friends, family, and strangers and the world will be a much better place.

Creak? What creak? My Record cranks dont creak, neither did any of my square taper Shimano from years back.

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What if the Hokey Pokey is what it is all about?

Square taper seems fine for the track lads- including Obree and Boardman.

FSA cranks are great, but there aren't many options in ISIS bottom bracket that have the sheer durability of a Record bb. I'm running a Truvativ crank with an FSA ISIS bb on my tri bike, and I'm expecting it to slowly loosen. I wouldn't harbor the same reservations with a 9spd Ultegra, a new Dura Ace or ANYTHING Campy.

'Sides, Record is a work of useable art that, even though it's carbon, can still easily grace the most techno-snobbish of bikes.

For the purely industrial look, I'd opt for a Zero Grav crankset. (That wouldn't match my road bike's classic aesthetics, but I could envision one on my tri bike.)

how 'bout the fsa srm? (it is megaExo)

g

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greg
www.wattagetraining.com

Don't bother with the ISIS - get MegaEXO and don't look back.

ah, you set me up. Like I said, I "heard" that they had a creak problem. I never said I felt that way.

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"And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country" JFK - Replace 'country' with the company you work for, friends, family, and strangers and the world will be a much better place.

FWIW, I have both. On bikes with compact cranks I have the FSA with ISIS. On the Record bikes, Record square taper. Both are nice. I have never, over 40 years of cycling, had an issue with square taper.

Get the Campy Record crank, then a FSA w/ MegaExo, then ISIS - my order for buying anyway.

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John Teeters
866-508-4676
john@triumph-multisport.com
http://www.triumph-multisport.com

Well the benefit of ISIS is that it is an open industry standard, unbound by patent rights and such, so anyone is free to use it. Unlike square taper.

It gives you a stiffer crank. Always a good thing ;)

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Unlike square taper?. What stops anyone from using square taper? There are more manufacturers using square taper than any other style.



Styrrell

Square taper is (was) a standard - everything had it untill ShimaNO decided they had a solution to the problem no one had.

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What if the Hokey Pokey is what it is all about?

Just a guess, so I am not sure, but does the ShimaNO Octalink BB design help with the self extracting bolt design? Perhaps the square taper requires higher tourque values, which would limit the abillity of the self-extracting bolt to not screw up the washer threads?

Not really defending the design, just trying to understand it.

Mark

Dude, 'twas a joke. Sorry, forgot to put the smiley at the end to make it REALLY obvious.

I switched to Octalink a few years ago from Campy square taper, only because the campy BB and chainset did not quite clear the chainstay. The Octalink gave me a couple of extra millimetres, without having to muck around with washers between the BB and and frame.

Octalink is no better, no worse, just different. I get 2-3 years out of an Ultegra BB, same as a set of Campy BB bearings. Most ISIS BB's have replaceable bearings, so there is no difference.

And I could never figure out if you were supposed to grease the tapers or not (show me a definitive source on THAT one.)

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This thread is really funny...

I had a conversation with one of the product design staff members at Campy several years ago. To paraphrase; "Yes, we know square taper is outdated. Yes we think oversize spindles are better, and the way to go. We won't make a larger OD BB until the bearing longevity issue for them is solved, and that will probably require a larger ID bottom bracket shell. We have designs in the works."

Phil Woods staff supplied, nearly word for word, the same answer.

The square taper bb is living on borrowed time.

Do some searching online, and check out pictures of the Italian Bike shows. You will notice that very few bike manufacturers are showing bikes with complete Campy groups - they all sub out the crankset. These shows are the engine that drive road bike design, and when companies like Pinarello and Colnago are swapping out the crankset on their show bikes, Campy takes notice.

They're working on it, and frankly, they need to hurry up...

(All Campy on my bikes. Except cranks. And brakes. And wheels. And front Derailleur....)



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Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

"better" better that what? Why? I am missing something...who here has actually felt their BB spindle flex and not have had the frame flex...or your shoe, pedal axel....

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What if the Hokey Pokey is what it is all about?

Excellent point, Chip.

Well Litespeed saw the light and went back to standard headsets (thanks Herbert), so can one person show me anything wrong with a Phil Wood BB that last 10- 20 years and a Campy crank set that goes on it.
My shop guys tell me horror stories about the external bearings that Shimano has been putting out, Like contamination problems in the first six months needing replacement. Why would you ever take bearings out of a protective shell and put them in the wetest and dirtyest area of the bike?
I really think there is a planned obsolecense in the Shimano bag of tricks. They sure went thru the Octalink logic pretty fast. In the short time they were out I was only able to buy a track crank and Dura Ace Octalink BB that lasted about 18 months before replacement. My Old fashioned free ball Shimano Dura Ace and Campy track BBs are ten years old and as smooth as I got them. Nice progress Shimano.

It's not an excellent point, it's just obstinancy. The difference in BB/crank stiffness with the new crank/bb designs is measureable and well documented. It does make a difference. It's not really arguable. The increment of improvement may be small, but it exists, and is empirically provable.

This is exactly the same argument as gets spewed about on ST regarding aero benefits of frames, wheels, well everything...

"I'm too slow to notice..." "If you aren't a pro, ride faster than 25mph, blah blah blah..."

As K Willet is fond of saying, "faster is faster."

Feel free to make an aesthetic value argument on these topics; on the BB topic, argue the longevity of the bearings. Don't pretend that you can make any kind of performance argument though, because you can't, at least in any logical, quantifiable way.





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Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

Bad application of a good idea does not invalidate the idea. The Litespeed Internal HS design has/had a couple of failings:

- relied on taper of Bearing set to self-center the races

- expensive to manufacture in the chosen material (TI)

- resulted in heavier bare frame weight, even if complete bike was lighter

- People who spend that much money on a frame feel a compulsive need to spend $100 plus on a headset, rather than the 15 bucks a comparable bearing set costs.

The problem with oversize BBs is that the BB cup standard is too small. Period. External cups are an attempt to deal with this, and are a temporary fix until the standard inevitably changes. Low bearing life is 100% a result of this.

I really get a kick out of these arguments regarding bearing interface design. I have asked the question before, and I will ask it again: if "internal" headset and BB designs are so bad, why is it that bicycles are the only common application that has not adopted this style of interface as (nearly 100%) the standard? If someone were to suggest, in a non-bicycle application, that a manufacturer press-fit an entirely seperate assembly into a tube, merely to support a press-fit sealed bearing, they would likely get laughed out of the room.



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Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

So are you saying that putting, say, a Dura Ace crank on a trek 1000 will stiffen the frame up? That's interesting. Where is the documentation on that?

No, I am not saying that.



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Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

Ok, so what exactly is the real world performance benefit of outboard bearings if you still have frame flex in the BB?

1) The primary purpose of external bearings in BBs is to allow the use of a larger OD BB spindles, which provide increased stiffness for the BB unit. Wider bearing stance does have a slight effect on stiffness, but this is a secondary design artifact

2) This stiffness is desireable, as the crank/bb unit is (obviously) a primary recipient/converter of muscular force. Stiffness in this unit results in increased efficiency in the transmission of muscular energy to the bicycle drivetrain.

3) The efficiency of this system can and should be optimized.

4) This optimization can be considered as a discrete operation, seperate from the considerations of frame design, other than as they effect the standardization of the design parameters.

Further:

"frame flex" needs to be usefully defined to be considered, and does not occur in nearly as simple a manner as would be readily apparent, especially as regards drivetrain function.

"frame flex in the BB" is essentially non-existant, if by BB we are referring to the BB shell. If by BB we are referring to an undefined bottom-ish area of the bike, than it does in fact occur, may well be the source of inefficiencies, and it's consideration is of absolutely no value in a discussion of the relative efficiencies of different crank/bb configurations.

EG: "Who cares how stiff my crankset is - I am riding in a 6 foot pool of peanut butter."

"Who cares how stiff my crankset is - I am riding a late 80's Vitus"

"Who cares how stiff my crankset is - It's mounted on a bike I never ride"

All good questions; all also completely irrelevent to the discussion at hand.



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Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/