ISIS - I give up!

[madcow]

FWIW, ISIS has the same spindle diameter as octalink, so the same bearing design restrictions apply to both.

That's what is commonly thought to be true in the industry. And probably why ISIS developers thought it wouldn't be an issue.

ISIS and Shimano are very close to the same OD....On the exposed part of the spindle.

ISIS is basically sealed cartridges(using both inner and outer races) pressed into a sleeve with a straight gauge spindle slid through the center.

The Shimano is completely different. It's commonly thought that it uses sealed cartidge bearings. When if fact it doesn't. As well, it doesn't even use a full compliment. There are only 7 bearings per row. The spindle starts at just under 22mm(the same as ISIS) but once you pass the first seal Shimano steps down to under 18.5. Get the 2nd seal and ball retainers out and you see that at the bearings, the spindle is actually a channel cup at only about 14mm....Basically a groove is cut into the spindle so that the balls can ride directly on the spindle. The end result is that the Shimano ends up with a bearing that is huge in comparison to the ISIS.

[Jan]

Anybody that know how sell SKF ISIS BB???

http://aebike.com/page.cfm?PageID=30&ac ... rch=Search

http://www.speedgoat.com/catalog.asp?cat=25



Also the new crankbrothers BB looks very good. 5 years warranty, and lower weight than SKF.

http://www.crankbrothers.com/cyan_tibb.php

[DaveS]

ISIS and Shimano are very close to the same OD....On the exposed part of the spindle.

ISIS is basically sealed cartridges(using both inner and outer races) pressed into a sleeve with a straight gauge spindle slid through the center.

The Shimano is completely different. It's commonly thought that it uses sealed cartidge bearings. When if fact it doesn't. As well, it doesn't even use a full compliment. There are only 7 bearings per row. The spindle starts at just under 22mm(the same as ISIS) but once you pass the first seal Shimano steps down to under 18.5. Get the 2nd seal and ball retainers out and you see that at the bearings, the spindle is actually a channel cup at only about 14mm....Basically a groove is cut into the spindle so that the balls can ride directly on the spindle. The end result is that the Shimano ends up with a bearing that is huge in comparison to the ISIS.

I've never disassembled an Ultegra or lower level BB, but it's not made the same as the DA model. The DA model uses both ball and needle bearings. It can be disassembled and serviced. The Ultegra model is not serviceable, so I've always assumed it uses cartridge bearings. The DA model is definitely not made as you describe.

http://bike.shimano.com/media/cycling/t ... 485009.pdf

You're not quite right about the ISIS. Although it obviously has cartridge bearings, they are pressed onto the spindle, not into a shell. The large diameter sleeve in the center is mainly just a spacer between the bearings. The threaded cups slides over the bearings and partially over the center sleeve.

[2 wheels]

We've been seeing that left arms falling off is becoming more common as these designs grow in popularity. I even know a couple of pro MTB racers that have had arms fall off in a race....

The left arm falling off in a race also happened to Discovery rider Benoit Joachim in last years Vuelta, but that was a Dura-Ace crankset:

I've been told that the main flaw Shimano found for the integrated involved left arm retention.

That's probably why Shimano has changed this design completely on the new XTR 2007 crankset. The next edition of the Dura-Ace crankset will probably have the same system as the new XTR 2007 crankset.

[FreaK]

that's partly why there are so many inventions to mount the arms, and partly why the 2-pc design is good, you at least have one arm that can't come off.

[madcow]

I've never disassembled an Ultegra or lower level BB, but it's not made the same as the DA model. The DA model uses both ball and needle bearings. It can be disassembled and serviced. The Ultegra model is not serviceable, so I've always assumed it uses cartridge bearings. The DA model is definitely not made as you describe.

http://bike.shimano.com/media/cycling/t ... 485009.pdf

You're not quite right about the ISIS. Although it obviously has cartridge bearings, they are pressed onto the spindle, not into a shell. The large diameter sleeve in the center is mainly just a spacer between the bearings. The threaded cups slides over the bearings and partially over the center sleeve.

It seems in my haste I did forget to stipulate which bb we were talking about. I assumed that we all knew the original DA7700 bb was complete crap in terms of durability. In that case you are certainly correct in that it was subject to the same restrictions as a standard ISIS. I was speaking of Shimano Octalink cartridges. However, it should be noted that just as 7701 was being phased out and replaced with 7800, Shimano had already begun producing the DA bb's in a cartridge version. They were available for a short time, and can sometimes still be ordered. I think Shimano did this as a backup in case the 7800 crank was a flop.

As for the ISIS description, I just tried to keep it as simple as possible. I assumed that everyone had a general idea of how they looked, which is essentially correct. A straight spindle pushed through bearings which press into the cups with a sleeve between them. Though not every bb uses this exact design, the idea is virtually the same in all of them.

The point being that in the ISIS, and DA 7700 bb's which use a consistent diameter all the way across, the bearings are always going to be a serious shortcoming. However, the cartridge Shimanos use a very unique method to approach the problem. But even with the serious reuction in diameter, Shimano still felt that bearing life was shortened over what it had been with Square.

The two piece design has definitely improved the bearing design(although alot of people complain about the increase in friction from the external seals), they have also introduced a new problem. The left arms falling off.

[baldy]

While I have seen many designs come and go, and will buy the Ultra torque record chainset when funds allow, have been using a square taper Campag track bb and c/set since 1985. I think that some people like to see flaws in all or are unlucky in their purchases. Most of us who race at less than pro level are never going to have the luxury of the most up to date equipment every year. I have never broken a bb or had any problems with them in over 30 years of riding. I wonder if some of the problems are bad installation? I know this is slightly off the track of ISIS but could it be a contributing factor? I never let my bike near my LBS and have never had issues. Just a thought...

[2 wheels]

I wish they will all adopt the new open BB30 oversize BB standard: http://www.bb30standard.com
The problem is it requires different frames. But the problem shouldn't be bigger than moving from 1" to 1 1/8" headsets.


The reason why ISIS was developed in the first place was because Octalink was patentented by Shimano and they wanted royalties from other companies to use it, so instead some Shimano competitors decided to develop their own open ISIS standard so they didn't have to pay Octalink royalties to Shimano foir all the crankset and BB's they manufactured.
If Octalink had been an open and free standard, ISIS would never have been developed.


The SI BB developed by Cannondale has now been made an open and free for all to use standard under the name BB30. The new open standard was first presented at this years EuroBike and they have created a website to promote the new standard: http://www.bb30standard.com

BB30 might experince competition from the new Shimano/Scott press fit bearings though. Scott has exclusive rights for these new Shimano press fit bearings the first year, but next year other frame manufactures can use the new Shimano press fit bearings too. The Scott Addicr R2 is the only bike with a BB designed for these new press fit bearings so far.
I hope this new Shimano standard will die out quick again and instead be taken over by the oversized BB3 standard. The oversize means stiffer and lighter cranks can be made and the bearings should be able to last longer. Cannondales SI / BB30 cranksets are lighter and even stiffer than Dura-Ace because of the oversize axel.

But a lot depens on what Shimano choose to do because they are the largets crankset manufacturer for race bikes; although a lot of Shimano equipped bikes are starting to be mounted with 3rd party cranksets from especially FSA. And now with the new SRAM groups we will also see more bikes equipped with SRAM (Truvativ) cranksets and if FSA comes out with their rumoured groupset as well, they they will also get a larger share of the crankset market. But Shimano is still the largest manufacturer and creates many of the trends other will follow.

[estone2]

After having built up a nice race bike for this season, but not ridden it much due to a house move, I find that my lovely bling FSA Carbon pro team issue crankset has a toasted ISIS bottom bracket.

Just took it to my local bike shop and they said they don't really carry ISIS BB's anymore as they are inherently poorly designed.

So do I carry on in the hope that I may get a good one? or just junk it and start again? If so, with what? I really like my kit to last!



Thanks,

Nick - fed up beginner weight weenie

I've got a Deda Ti BB and love it. It's 162g if I remember correctly, so it's relatively light.
I would stay away from FSA's offerings, but that's just me.
-estone2

[Provence]

Reading everyones comments concerning b/b standards has intrigued yet worried me about the future. Unfortunately I've come to the sorry conclusion that square taper is, in fact, the best system to date. For example it's been 'good enough' for countless pro's over decades of racing in the most prestigious events. Has proven stiff enough for the likes of Merckx, Cipollini and Boonen to name but three gear mashers. What I'm saying is I think the cycling industry is trying to fix a problem which simply doesn't exist and in their eagerness to kill square taper has created a monster which is currently out of control. Only time will tell whether or not it can be tamed.

[estone2]

Reading everyones comments concerning b/b standards has intrigued yet worried me about the future. Unfortunately I've come to the sorry conclusion that square taper is, in fact, the best system to date. For example it's been 'good enough' for countless pro's over decades of racing in the most prestigious events. Has proven stiff enough for the likes of Merckx, Cipollini and Boonen to name but three gear mashers. What I'm saying is I think the cycling industry is trying to fix a problem which simply doesn't exist and in their eagerness to kill square taper has created a monster which is currently out of control. Only time will tell whether or not it can be tamed.

Experimentation and change is good, though. Look at the first TVT Carbon frames, and the first carbon frames in general. They were often flexy, always very heavy, very expensive, et cetera.
There are always going to be fads and new ideas, and there will be flops, and there will be failures, but they will evolve into better things (or die out), leaving us with a better product in the end.
-estone2

[Skyleth]

I've read all the posts and have some questions... and let me get this right, ISIS refers to the entire BB system? Splines, Axel, Spindle, Bearings, etc...? I thought it was just the splines... in that case, what would differentiate a FSA ISIS BB from an AM Classic or KCNC if they're all using the same design top to bottom? Quality of materials?

on top of it all, I just saw at the USGP of 'Cross #1 and #2 races that Crankbrothers has a new ISIS BB out, is this the same as the not so good/long living FSA/AMClassic ones or is it of higher quality? Someone mentioned this BB but I didn't see any replies.

tia

[estone2]

I've read all the posts and have some questions... and let me get this right, ISIS refers to the entire BB system? Splines, Axel, Spindle, Bearings, etc...? I thought it was just the splines... in that case, what would differentiate a FSA ISIS BB from an AM Classic or KCNC if they're all using the same design top to bottom? Quality of materials?

on top of it all, I just saw at the USGP of 'Cross #1 and #2 races that Crankbrothers has a new ISIS BB out, is this the same as the not so good/long living FSA/AMClassic ones or is it of higher quality? Someone mentioned this BB but I didn't see any replies.

tia

They're all slightly different designs, although they all serve the same purpose. They're probably a similar quality material, as no company can really get away with making inferior products any more. FSA has had a lot of trouble with their ISIS BB's however, in terms of coming loose; it has a worse history than many/all other mfg's, that's all.
-estone2

[snoopy]

We've been seeing that left arms falling off is becoming more common as these designs grow in popularity. I even know a couple of pro MTB racers that have had arms fall off in a race....

The left arm falling off in a race also happened to Discovery rider Benoit Joachim in last years Vuelta, but that was a Dura-Ace crankset:

I've been told that the main flaw Shimano found for the integrated involved left arm retention.

That's probably why Shimano has changed this design completely on the new XTR 2007 crankset. The next edition of the Dura-Ace crankset will probably have the same system as the new XTR 2007 crankset.

The problem with Shimano and others using same system.If you tight it too tight it will be loose on the opposit side of the bults.On D-A shimano recomend 12-15newton but I suggest about 20.When you go over 20 left crankarm go off.

[Boonen]

What always made me wonder a bit is why nobody used the shimano-octalink design priciples with the spindle beïng more narrow on the inside to create an ISIS bb that would work. The biggest problem with these (I think) is the small bearing size. I don't really see why there couldn't be a good working ISIS compatible bb made. Maybe it would be a bit less stiff then most ISIS bb's? It chould be just as stiff or stiffer then the square taper bb though and be just as durable. I realize this would be a product with no/very little improvement over the square taper bb (maybe the attachment, but I doubt it) but it would be a good alternative for all the people with ISIS cranks that ride a lot and are fed up with changing the bb every time. I have an octalink bb in my mtb that works very well after many km's (>10k mtb riding for sure) but can only hope I can find a descent bb when it ever wears out ... I really like the new campy design, but still think there is something to say for a phil wood/power arms combo.