Square Taper or Octalink ?

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  • this doesn't look to have been covered anywhere as i can see...

    I'm deliberating between 7710 and 7600 Dura Ace track Cranks which are octalink and square taper respectively.

    from what i can gather it seems that the octalink makes for a stiffer crank compared to square taper.

    however i have heard stories that the octalink interface is a bit weak and can shear the the crank interface....
    but that's the thing,
    i don't really know cos i've never had an octalink crankset,
    so your input would be much appreciated.

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  • I probably shouldn't be posting, as I haven't used either of the Octalinks, however I have used square taper and isis, and of the two I prefer the square taper. Reasons are 1) I had a severe creak failure with isis on a relatively new bike,i.e. after less than a year, and having more than one bike, it was not used a lot. 2) Square taper has been around in 2 forms for a long time, and is tried and tested. I have two sets of Dura ace track cranks, both square taper, and they are top quality. Hopefully somebody with Octalink experience will reply also.

  • all I can say is I rate my 7710 cranks hard. Super stiff

  • Square taper seems perfect, I'm not really sure why it needed reinventing. Maybe someone can enlighten me.

  • Loose weight, gain rigidity, stable chainline.
    Unfortunately, they forgot about BB shell diameter, ball size and BB-set durability.
    Not to mention standardisation, but that word doesn't exist in the bike branch dictionary...

  • Using a torque wrench and correctly tightening ISIS and Octalink cranks has never left me with creaking cranks or any other sort of crank failure. Square taper works but it's a bit like running a quill stem.

  • looking at the images, I don't think the depth of the notches is sufficient in octalink v1 hence their update to v2

  • My 7600 Octalink notches sheared a little on the non-drive side and needed to be glued, I'd have gotten square taper if I could go back in time. (BLB's Jan advised against Octalink for fixed and ridiculed me somewhat when I told him what happened.)

  • ISIS longevity = FAIL

    I'd be loath to try Octalink for similar reasons.

    Square taper's fine.

    But I'd like to see everything go down the external BB/ultra-torque/blah route. Pity there's fuck all choice in track chainsets at the moment (don't want Omniums).

  • Square taper.

  • I've got an own-branded Cannondale set on the road bike with the BB30 shell, I believe the crankset is made for Cannondale by FSA.

    Whatever- they are extremely stiff, and pretty light.

    On the track bike I have ISIS, again FSA. Seems to work but only four months old.

    That said I have an unused FSA Platinum Pro BB waiting in my toolbox should the current BB give up the ghost.

    I'd rather try the newer ideas, albeit after seeing which ones go the way of Betamax/HD DVD first.

  • What a nonsense argument. If the internet had been around when they were chaging from coterless to square taper this forum would be sayiong that coterless doesn't need changing, works fine for me, blah, blah, blah.

    It's newer, it's better, job done.

  • This is the one that I have on the road bike- what would it be called?

  • Crack'n'fail Splined Shite I think is their marketing term for those.. ;)

  • Is that why Specialised are now going to the BB30 standard after Cannondale have used it for a few years?

  • this is what wikipedia writes (yes yes i know, but still)
    This system was designed by Shimano. The Octalink system provided a greater contact area between crank and spindle, so it had a stiffer interface. Octalink exists in the marketplace in two variants, Octalink v1 and Octalink v2. The difference between the two can be seen by the depth of mounting grooves on the bottom bracket spindle. XTR, 105, Ultegra 6500 and Dura Ace 7700 cranksets mate to version one bottom brackets, while more recent mountain bike designs use the deeper-grooved version two. The system is proprietary and protected by Shimano patents and licence fees, thus relatively few companies aside from Shimano produce Octalink cranksets. Many competitors have adopted the square taper and ISIS designs as an alternative. In use, Octalink has been shown to loosen because it is not a taper-fit but merely a tight spline fit. Reverse torque loads can cause the crank bolt to undo, and the crank can be irreparably damaged if this is not checked.*

  • Is that why Specialised are now going to the BB30 standard after Cannondale have used it for a few years?

    Let Cannondale fall apart like usual, iron out the bugs, release proper cranks. Job done :)

    BB30 is just a standard anyway.. it doesn't define the cranks: http://velonews.com/article/13862

  • In other words,

    Octalink is more stiff than Square taper, but less durable and practical.
    It is not taper-fit so the crank doesn't sit snugly on the spindle and has been shown to undo the bolt and damage your cranks. Also because Octalink has a thicker spindle, the bearings are smaller, making them wear out quicker.


  • Thanks but on my good bike I'll go for the stiffer cranks and tighten them properly. On the other bikes.. meh^100.

  • Who invented the BB30 standard?

  • No idea. It's a "standard" not a crank.

  • Don't forget that there are two types of Square Taper. JIS and ISO which can, theoretically, be mixed and matched to mess with chainline.


    ISO Crank on JIS square taper bb will be 4.5mm further out than on an ISO square taper bb.

    Miche FTW.

  • Cannondale invented it, now Specialised have started using it as they recognise that it is a good idea.

  • I'm not saying the idea is bad.. I'm saying that Cannondale are bad :P

    Defensive ain't ya? heheh

  • Meh.

    My Cannondale was the last to be made outside of Taiwan anyway, so it's only the IP that seperate them from Specialised/Trek etc now.

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Square Taper or Octalink ?

Posted by Avatar for Dylan @Dylan