Haufigga

One better than the other? FSA Carbon cranks come in both styles, and I can't decide.

thanks,

-Tak

itschris

While you're at it, can you explain the difference? Until 2 months ago, I had never heard of ISIS.

tommy2pants

It's a splined spindle system similar to but not compatible with octalink. Dreamed up as a standard by a group of other aftermarket suppliers. Seem to be alot of issues with premature bearing failures.

robertsdvd

I likeee the ISIS... never used Octolink though... I like ISIS much better than the tapered what-have-you's.

Phatman

octalink. its a lot easier and cheaper to get a shimano octalink bb then it is an ISIS. I know from experience here...

robertsdvd

They must have the Octolink BB's at CVS then ; because I haven't had a bit of trouble finding ISIS ones in all flavors... bikeman.com has good prices on'em for one and its a local shop (ok, in Maine, but its still a "local" shop with a physical location)...

Phil from VA

I use both, and really like the FSA Isis. I think the old Dura Ace was a terrible design - too many parts, but I just bought a new one that is 2 piece like everyone elses. Some people complained that the DA needle bearing design created a lot of drag, but I don't know.
I'd give a slight preference to the FSA Platinum Pro over the DA.

tommy2pants

All octalik is not DA.Nothing wrong with the DA bb,but one has to know how to install it and too many don't have a clue. DA is actually smoother,and with less deag.All in the installation and adjustment.The clueless should just quit griping and stick with ultegra.

Phil from VA

I'm not disputing what you say, except your statement that DA has less drag. I don't know if that is true. I'm sure there is some website in Germany that has bench tested 20 BBs, but I have not seen it.
If the DA design is so good, why did the get rid of it? I've installed a dozen or so, and I think the old design stinks. Please don't tell me that it was just too complex for the average human.

tommy2pants

It's just not DA that shaimano has dumped. Octalink will be history. DA does get alot of bad press and it is from the average human that does not install it right.The average human should probably just stay away from it, but they can't becaues it's DA ,cost more and weights 49 grams less.

HarryK

I've got an FSA ISIS on the new bike, with the Megatech OS BB. The bearings are standard industrial bearings which just sit in the BB, so easy to obtain in the unlikely event they ever wear out.

I like the "open-standard" with ISIS and the Megatech BB...encourages the aftermarket and small frame builders. Shimano doesn't need all my business.

Don't notice any drag with this set up either. Compared to the drag of the chain, BB drag should be insignificant.

tommy2pants

What does small frame builders have to do with it?

BikeInMN

Good Question...

ISIS has had it's share of failures.

LINK

Due to the over-sized spindle, the bearings are smaller and may wear faster. In mountain biking applications, ISIS failures are quite common if you believe the reviews on MTBR.com. I'm not sure how long they'd last on a road bike but why even mess with it when Campy and Shimano make perfectly fine products.

As for stiffness, the new 04 DA should be far stiffer than either Octalink or ISIS. Also, I've raced for the last two seasons on Chorus BB & Cranks and it's been plenty stiff IMO and don't know if I'd even notice a small percentage difference.

georgesnatcher

As far as Octalink goes I love it. Have it on both my road and mtb. When it comes to Campy though I have yet to find a square taper BB that I don't end up having to re-tighten the crank arms every 2-3 rides. Octalink on the other hand never seems to loosen.

MichaelW

Is Yet Another standard, which solves the ISIS bearing problem by using an extra-fat bottom bracket shell. Apart from providing room for larger bearings, the BB shell also gives a larger area for welding fat Al frame tubes.

tommy2pants

That's just because you never did it right, or you rode it while loose, and buggered the arms and then it never will stay tight.

HarryK

Aren't Cannondale and others are going to their own proprietary oversize BBs, away from the cartridge style? ISIS/Megatech give independents a way to go to oversize BB's as well on frames they build. If this is incorrect, please enlighten me.

tommy2pants

Not incorrect,but maybe a solution looking foa a real problem.

OneTinSloth

i have an octalink BB. and while i've had virtually no problems with it so far (aside from my left crank arm coming a bit loos every once in a while) i really hate it. mostly because i don't trust the tiny, 3mm of splines that the crankarm is grabbing onto. i'd prefer to have an ISIS BB, just because there is more contact between the crankarm and the spindle. the ISIS failure that sheldon brown mentions was due to a really crappy design flaw in the spindle design, not so much the splines...

having said all that, of the three major types of bottom bracket designs, i prefer square taper. campy has been doing it for decades, and why bother changing something that works pretty flawlessly to begin with?

sidewinder

Check https://www.truvativ.com.

You will find that TruVativ explains the ISIS BB very well.

As far as weight goes, the TruVativ Elita crankset is lighter than the comparable Ultegra crankset. So, if there's any weight advantage to the Octalink bottom bracket, it will be more than offset by the weight difference in the cranksets.

My last bike had a TruVativ Elita crankset and ISIS bottom bracket. Though I put thousands of miles on the bike, I never experienced a bit of problem.

According to TruVativ, the ISIS system is also more foolproof, so the local wrench, who may or may not know what he or she is doing, is less likely to muck up the installation or repair.

late

They are both very good. I haven't had a bike with ISIS, but it looks good, and people seem to like it. I have an Ultegra BB, and anything that survives my tender ministrations is pretty good.

HarryK

Shimano used the square taper for many years also with fine results. I think it's mostly about weight savings.....a hollow axle with some kind of splines should be lighter. Plus, I believe the crank arms can be designed lighter as well.

We could argue the value of saving a couple of ounces on a BB, but it seems that the quest for lighter weight has a great sales appeal.

OneTinSloth

but....octalink spindles are bigger than square taper spindles...

i think if anything, it's more about strength than weight. BMX cranks had been using splined bottom brackets for years before shimano started doing it.

a round spindle might be stronger, but i still don't trust the thin-ness of the splines on octalink...i have heard a number of reports that the 105 cranks "stripped out" because the aluminum was too soft or something...which was why i went with an FSA gossamer crank instead. i highly doubt that i'll ever have a problem with any of it...

HarryK

But aren't octalink and isis spindles hollow, vs the solid square taper spindles? A bigger diameter, hollow spindle would be lighter and stiffer than a solid one.

Agree the ISIS splines look pretty strong. And I'm sure not expecting any problems with my new FSA Team triple crank coming loose either.

OneTinSloth

all of the square taper spindles i've ever seen have been hollow as well...i'm looking at an older campy cartridge BB with a hollow square taper spindle right now, and the suntour track spindle that i have is hollow, and the shimano UN52 BB that i have on another bike is also hollow.

are you thinking of the REALLY old crusty spindles that have the "male" threads sticking out of the spindle and use nuts to hold the crankarms on?

octalink and ISIS are both oversized, and therefore stronger than standard square taper spindles. i think there are definite advantages to them, but mostly i feel like they relate to the mountain bike world where the bikes have to take more of a beating.