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ISIS vs. Octalink?(8 posts)

ISIS vs. Octalink?my327vette
Nov 16, 2003 2:18 PM
Hi, one of my off-season upgrades that I would like to make this year is to purchase a pair of FSA Carbon Pro Team Issue cranks. I currently have a full Shimano Ultegra group on my bike. My question is whether I should get them to accept an ISIS bottom bracket or a Shimano Octalink bottom bracket. The reason I want to upgrade the cranks is because I weigh 185-190 pounds and would like a pair of cranks with as little flex as possible, but I know that I can get an ISIS splined bottom bracket that will be lighter than the Shimano. So i guess my question is, will the Octalink bottom bracket have less flex than the ISIS, and if so is it a noticable enough difference to warrant the extra weight over the ISIS? Also, will the shimano bottom bracket be more durable than the ISIS? Thanks.
re: ISIS vs. Octalink?glia
Nov 16, 2003 5:48 PM
Based on the latest review in Velonews you would be best off with the new 2004 Dura-Ace crank. Stiffest in its class and has an integrated BB.
re: ISIS vs. Octalink?al0
Nov 19, 2003 12:06 PM
By the way, the same review states that Ultegra is much stiffer then FSA and slightly stiffer then 9-sp DA, so you plan downgrade, not upgrade :( 10-sp DA is really stiffer, but I'm not sure what else you need to upgrade to make this upgrade work.
May come down to availabilitypitt83
Nov 17, 2003 7:34 AM
When I was building my cross bike, the Octalink FSA gossamer was sold out "for the forseeable future". The ISIS has been just fine. I did have to spend the extra $$$ for the ISIS BB tool, but whenever I get that indefinate backorder, I'll scramble and get something workable.
Before you do anything read all this....russw19
Nov 17, 2003 11:56 AM
You have a couple of points in your post that need addressing. First off, the Dura-Ace bottom bracket is lighter than all the ISIS bottom brackets I know of with the exception of the American Classic. The FSA Platinum Pro Ti is 1 gram lighter than the Dura-Ace. But the Dura-Ace is cheaper. And you could always upgrade your BB and use your current crank.

That brings me to the second point... your Ultegra crank is (slightly) stiffer than the FSA Carbon Pro crank already. If you are looking to upgrade to carbon cranks because you like them and think they are cool, fine, but they ARE NOT stiffer than your Ultegra cranks. There was a test done last year that matched up the Dura-Ace, Ultegra, FSA Carbon Pro, Ritchey Pro, and some other crank in a stiffness test. The Ultegra scored higher than the Carbon cranks did.

Now, that all said, here's a few points worth considering about Shimano and Octalink. Shimano has already shown that Octalink is in planned obsolescence. The 04 Dura-Ace doesn't use it. Meaning that if Shimano follows their well established trickle down upgrade pattern that they have used for the past 25 years, next year Ultegra will use the outboard bearings and 2 piece crank design, 105 will get it in 2006, and so on down the line. So the knock against Octalink is that is will soon be a dead pattern. But then to be fair, by the time you can no longer get the parts to replace it, you most likely will have replaced that whole bike. But keep in mind that Octalink will slowly be phased out over the next few years.

As for your question about flex between the Octalink and ISIS bottom brackets... I have never seen a test on that, but the stiffest spindle money can buy is said to be that of XTR. But I would imagine that the stiffness between ISIS and Octalink is right on par with each other. It is also worth noting that no test has ever proven that Octalink or ISIS spindles are any stiffer than the spindle of a Campy Record BB. They score just as well in tests as the others do.

The thing about your line of thinking is that you seem to want to focus on every issue except aesthetics for your decision, and normally that is a good thing to do, but when it comes down to it, that is really the only factor that is going to make a big enough difference to sway you one way or the other. That and price.

But if you want stiff, stick with your current set up. If you like the look of a carbon crank, spend your money and have fun. But the truth is that you won't notice any difference in a blind test either way.

When you ask about the durability of the Shimano BB over the ISIS, it all depends on which BB you get and if you install it correctly and do the required maintenance. I have a Dura-Ace BB that has over 40,000 miles on it, that's about as durable as a BB gets. But you have to take care of it and overhaul it if you get water or dirt inside. You don't have to do that with the Ultegra, nor most ISIS BB's because they are a sealed non-serviceable unit. That can be both good or bad depending on your riding style and maintenance habits.

So what it really comes down to is that you should buy what makes you the happiest because that is the only real measurable difference when talking about high end Shimano cranks and BB's vs. stuff like the FSA carbon cranks and good ISIS BB's. Pick up that carbon crank if you like it.. if it makes you ride more then you chose well.

Other possible outcome...PsyDoc
Nov 19, 2003 5:39 AM
...the new DA stuff does not sell well and Shimano keeps making both styles of cranks. Granted...this outcome is not likely, but you never know. I would not be surprised if Shimano keeps making the octalink BB for as long as it is profitable to do so, which could be for many, many years.
The reason I don't think so..russw19
Nov 19, 2003 11:35 AM
The Octalink Spindle it too expensive to make compared to a steel square taper spindle. That's why you don't see it on the low end parts. It's a performance upgrade, but the people riding the low end stuff don't need it. So once the high end moves away from Octalink to the new Dura-Ace/XTR/XT outboard bearing design, I think Octalink will fade away. However, as I alluded to in my earlier post, that change is still 5 years from now by the time that design trickles down to groups like Sora and Alivio on the offroad side.

re: ISIS vs. Octalink?AJS
Nov 18, 2003 5:32 PM
The cranks I'm currently using are Truvativ Elita's with the ISIS, and I've not had a problem yet. Very good stuff, especially for the price.