Results 1 to 33 of 33
  1. #1
    mtbr member
    Reputation:
    Join Date
    Nov 2006
    Posts
    330

    why does octalink suck so bad

    A lot of riders hate the octalink system and a bike shop has told me Shimano is discontinuing it. Why? Aren't XT and XTR using it?

  2. #2
    No, that's not phonetic
    Reputation: tscheezy's Avatar
    Join Date
    Dec 2003
    Posts
    14,313
    Octalink is actually a very good system. However, "progress" marches on and Shimano decided to come up with a new standard in the form of external bearing bottom bracket cranks. Isis is the system that sucked, and maybe that is what your lbs was referring to. Isis is a spline interface system designed to copy Octalink, but the bb durability was horrible. Good riddance to that. Shimano still makes Octalink bb's and probably will for a while as replacement parts. LX, XT both used Octalink, but XTR used a different spline pattern (thanks, Shimano ). The new external bearing cranks are supposedly stiffer, but the bearings are not as well sealed as the Octalink was imo, but are easy to work on which Octalink was not. It is a trade-off. No free lunches, I guess...
    My video techniques can be found in this thread.

  3. #3
    mtbr member
    Reputation: itsdoable's Avatar
    Join Date
    Jan 2004
    Posts
    1,902
    The main issue with Octalink was it was prone to creaking, as the spline interface was not an interference fit. Very few Octalink cranks, especially the mid-lower end ones, stayed quite over the long run. However, the bearings lasted well, and if you didnot mind the noise, it held up well. The newer external system is less prone to creaking, and the bearings have been holding up reasonably well (Shimano's, not Race Face's) and are cheaper to replace.

    ISIS has a poor rep due to 2 major problems - bearings were too small - minimal contamination destroyed it, and the tolerances on the spline interface was not tight enough to ensure compatibility between manufacturers, and sometime with the same brand.

  4. #4
    damaged
    Reputation: npoak's Avatar
    Join Date
    Jan 2007
    Posts
    35
    Oh god. The ISIS debate begins again. I have ridden ISIS BBs for sometime and will continue for sometime. I've never had a problem and logged over 5000k on the same FSA mid level BB last year. External BBs are a great idea but the Q-factor still kills me. I don't have alot of good to say about anything Shimano but Octalink wasn't that bad. No system is perfect, they all have issues. it's just finding what works for you needs. ISIS has worked, and keeps working for mine.

  5. #5
    i don't give a shift
    Reputation: collideous's Avatar
    Join Date
    Jul 2006
    Posts
    863
    Never had an issue with ISIS nor the newer cartridge type Octalink BBs. Never thought my square-taper BBs weren't stiff. External BBs are only as good as the machined precision of the BB shell. By design it's easy to end up with more friction. It's going to be history as soon as frame builders adopt a larger BB design such as BB30.
    blogging @29in.CH

  6. #6
    damaged
    Reputation: npoak's Avatar
    Join Date
    Jan 2007
    Posts
    35
    Quote Originally Posted by collideous
    It's going to be history as soon as frame builders adopt a larger BB design such as BB30.
    That I agree with. External BBs are yet another BB solution that is hot now but is ultimately a flash in the pan, like ISIS was....etc.


    I can't comment on the BB30 beyond the only company I loath more than Shimano is Cannondale...but must say I like the idea of it, though it seems iffy at best if the industry will adopt it. Cannondale doesn't really have alot of force for change anymore.
    Last edited by npoak; 01-03-2007 at 12:15 PM.

  7. #7
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by tscheezy
    ...The new external bearing cranks are supposedly stiffer, but the bearings are not as well sealed as the Octalink was imo, but are easy to work on which Octalink was not. It is a trade-off. No free lunches, I guess...
    Their (and most other brands) external bearing BBs (except for '07 XTR) have no provision for bearing adjustment. This means if the BB shell is not exactly the right width (very unlikely) the bearings will bind and/or fail quickly.

    The one-piece cartridge BBs need no adjustment (self contained) and the classic loose ball and fixed/adjustable bearing cup BBs are totally adjustable.
    mtbtires.com
    The trouble with common sense is it is no longer common

  8. #8
    Blanco
    Reputation:
    Join Date
    Nov 2004
    Posts
    1,332
    The best would be to adopt one of the BMX standards like Spanish or Mid BB. Simple, proven, plenty of 3pc cranks already available. I don't know which one will win, but they're both basically the same thing.

    It's funny how BMX has had splined crankarms that don't creak for decades, but the mountain bike people still can't figure it out.

    BB shell width doesn't matter with Spanish or Mid BB, since the axle is separate from the crankarms, and the BB cups just press-fit into either side of the shell. Easy to tune chainline, BB is the same no matter what shell or cranks you have, new BB cups/bearings are trivial to swap out (most BMXers just do it with a hammer and a piece of wood).

  9. #9
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by El Caballo
    The best would be to adopt one of the BMX standards like Spanish or Mid BB. Simple, proven, plenty of 3pc cranks already available. I don't know which one will win, but they're both basically the same thing.

    It's funny how BMX has had splined crankarms that don't creak for decades, but the mountain bike people still can't figure it out.

    BB shell width doesn't matter with Spanish or Mid BB, since the axle is separate from the crankarms, and the BB cups just press-fit into either side of the shell. Easy to tune chainline, BB is the same no matter what shell or cranks you have, new BB cups/bearings are trivial to swap out (most BMXers just do it with a hammer and a piece of wood).
    If the Mid BB cranksets work like most of the BMX cranksets/BBs (Profile and such), the lack of an adjustable cup can still cause bearing binding and/or early failure if the BB shell is slightly off spec (been there).

    They can still creak, too.
    mtbtires.com
    The trouble with common sense is it is no longer common

  10. #10
    mtbr member
    Reputation:
    Join Date
    Nov 2006
    Posts
    330
    [QUOTE=npoak]Oh god. The ISIS debate begins again. QUOTE]

    Thanks npaok. I'm still laughing. Good way to start the day.

  11. #11
    Blanco
    Reputation:
    Join Date
    Nov 2004
    Posts
    1,332
    Your guide to BMX bottom brackets. "Euro" is what all mountain and road bikes use.

    http://www.danscomp.com/serve.php?se...aringchart.htm

    Actually, with Spanish and Mid you don't even have a bottom bracket in the traditional sense: you just press-fit the bearings directly into the frame. Light, simple, works.

    Yes, it's possible for 3pc cranks to creak, but experience suggests it's a lot less likely. Even a 3pc Euro setup is less creaky because the splines are better and there are so many ways to tighten or adjust everything.

  12. #12
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by El Caballo
    Your guide to BMX bottom brackets. "Euro" is what all mountain and road bikes use.

    http://www.danscomp.com/serve.php?se...aringchart.htm

    Actually, with Spanish and Mid you don't even have a bottom bracket in the traditional sense: you just press-fit the bearings directly into the frame. Light, simple, works.

    Yes, it's possible for 3pc cranks to creak, but experience suggests it's a lot less likely. Even a 3pc Euro setup is less creaky because the splines are better and there are so many ways to tighten or adjust everything.
    I know what the sizes are. The 'Mid" is still a BB, no matter how the bearings are fixed to the frame.

    It is the manner in which the BB/spindle/cranks are assembled and the provisions (or lack there of) for adjustment that concerns me. Most BMX setups are in the "lack of" category. Yes, I would like to see larger BB shells in mtbs for larger bearings. No, I do not want the BB/cranks used to mimic the BMX norm (except for the floating spindle).

    You are right that my Profiles with an (FSA X Drive- has an adjustable cup) euro BB does not creak, but it does clunk because the crank splines have wallowed slightly. Different stresses in XC/trail mtb use than BMX/street/DJ.
    mtbtires.com
    The trouble with common sense is it is no longer common

  13. #13
    Mantis, Paramount, Campy
    Reputation: Shayne's Avatar
    Join Date
    Jan 2004
    Posts
    4,701

    Another 25 Year Old Idea Comes Around Again

    Press fit BBs made the go around a while back. They worked with basically every available crankset at the time but still didn't stick around for long.

    I love press fit BBs and I only own threaded BB shell bike but I don't think BB30 will get very far until spindles are available for any crank.
    *** --- *** --- ***

  14. #14
    mtbr member
    Reputation: itsdoable's Avatar
    Join Date
    Jan 2004
    Posts
    1,902
    Quote Originally Posted by shiggy
    Their (and most other brands) external bearing BBs (except for '07 XTR) have no provision for bearing adjustment. This means if the BB shell is not exactly the right width (very unlikely) the bearings will bind and/or fail quickly...
    Is bearing adjustment really necessary as long as you have pre-load adjustment on the cranks? You can adjust pre-load on the Shimano external systems, but not on the RaceFace X-type as far as I know.

  15. #15
    mtbr member
    Reputation:
    Join Date
    Apr 2004
    Posts
    8,292

    Q factor

    I know what Q factor means, but can somebody tell me the difference in Q factor (width from one side of the cranks to the other) between XT-752 (octalink, which is what I've got on two bikes) and XT-760 (integrated bb). I know there's different width bb shells, but I'm talking relatively. OK, maybe I don't know exactly where it's measured--at the bb or the end of the crank arms? I never got the newer-style cranksets from Shimano because my octalink-style cranks have never creaked and they feel just right. A wider Q factor I always figured would mess up my geometry down there.

  16. #16
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by itsdoable
    Is bearing adjustment really necessary as long as you have pre-load adjustment on the cranks? You can adjust pre-load on the Shimano external systems, but not on the RaceFace X-type as far as I know.
    That "pre-load" is bearing adjustment and yes it is important. As far as I can tell from reading the installation instructions of the various external BB cranks, only the '07 XTR has it. Everything else relies on the BB shell being exactly the proper width. I have seen numerous posts about how "stiff" the bearings are on these type of cranks and I think this is the major factor in that.
    mtbtires.com
    The trouble with common sense is it is no longer common

  17. #17
    mtbr member
    Reputation: itsdoable's Avatar
    Join Date
    Jan 2004
    Posts
    1,902
    Quote Originally Posted by shiggy
    That "pre-load" is bearing adjustment and yes it is important. As far as I can tell from reading the installation instructions of the various external BB cranks, only the '07 XTR has it. Everything else relies on the BB shell being exactly the proper width. I have seen numerous posts about how "stiff" the bearings are on these type of cranks and I think this is the major factor in that.
    I have only installed LX and XT external bearing cranks, both use a plastic threaded cap to apply pre-load (similar to aheadset pre-load) before tightening the pinch bolt. Both cranks spin smoothly and freely. If the pre-load is not properly applied, then the cranks have a tendency to come loose.

    I have less experience with X-type (RF) but I do not see any pre-load adjustment on them, we have a few in our group, and they are having similar problems with the ISIS-type spline interface as with the old ISIS standard.

  18. #18
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by itsdoable
    I have only installed LX and XT external bearing cranks, both use a plastic threaded cap to apply pre-load (similar to aheadset pre-load) before tightening the pinch bolt. Both cranks spin smoothly and freely. If the pre-load is not properly applied, then the cranks have a tendency to come loose.

    I have less experience with X-type (RF) but I do not see any pre-load adjustment on them, we have a few in our group, and they are having similar problems with the ISIS-type spline interface as with the old ISIS standard.
    I can see how that could work. The instructions only tell you to tighten to a specific torque setting with no mention of checking the bearings for binding or looseness, though.

    I would prefer that the crank arms were not used in the preload adjustment (or affect it) at all.
    mtbtires.com
    The trouble with common sense is it is no longer common

  19. #19
    otb club member
    Reputation: Chris2fur's Avatar
    Join Date
    Jan 2004
    Posts
    2,726
    Quote Originally Posted by shiggy
    I can see how that could work.

    I would prefer that the crank arms were not used in the preload adjustment at all.
    Shiggy, the standard Hollow Tech II system works great. The end cap can be fine tuned (similar to a headset adjustement). The opposing pinch bolt on the crank arm works great for locking the system in place. Some of the FSA crankarms use a very similar "preload" adjustment system. The main reason for the 07 XTR change was weight savings. They found that a lot of material was required to make the crank arm strong enough where the pinch bolts are located. Now that the small tension ring on the new XTR adjusts and locks the axle, a "standard" (read: lighter) crank arm can be used.

    The other systems that require special spacers that must be "just right" are a real pain. I think a lot of the pre-built bikes with these cranks are not set up correctly to begin with.

  20. #20
    Old man on a bike
    Reputation: Bikinfoolferlife's Avatar
    Join Date
    Feb 2004
    Posts
    12,383
    Q-factor is trying to give a measurement for the distance between your feet, so if you're measuring a crankset you measure from the outside of the crankarm at the pedal (and if you're really picky about your q-factor then you have to look at your pedals as well, they're not all created equally).
    "...the people get the government they deserve..."
    suum quique

  21. #21
    the goose is loose!
    Reputation: rm_racer's Avatar
    Join Date
    Feb 2006
    Posts
    1,276
    truvativ had a good idea by capturing one bearing race between a step in the spindle and left crank arm, but it still relies on the perfection of the cups and bottom bracket. i think an isis-type design, but with a larger bb shell with larger bearings that are sealed off better--and with better seals on the bearings themselves and then some extra seals such as crank brothers it doing--would make a pretty good bb. no fussing with preload of the bearings, minimized interference from shell inaccuracies, and a pretty easy installation. i think isis would work if there was a bigger shell for it to go in.

  22. #22
    Blanco
    Reputation:
    Join Date
    Nov 2004
    Posts
    1,332
    Quote Originally Posted by shiggy
    It is the manner in which the BB/spindle/cranks are assembled and the provisions (or lack there of) for adjustment that concerns me. Most BMX setups are in the "lack of" category.
    Preload is adjusted by moving the crankarms -- just like moving the stem to adjust bearing play on a headset.

    My question to you: how would *you* construct the crank/frame interface? What are the problems that none of the existing designs address, and how would you solve them?

    (I like American and Mid BB because they're so heinously simple and cheap. No buying "bottom brackets", just standard size replacement bearings available from any number of industrial supply places. Want to go deluxe and get tapered roller bearings? Buy them yourself and avoid the extra markup of a bike parts manufacturer, distributor, and retailer selling you the same things in a threaded enclosure. The only argument I see against this is that ham-fisted folks could damage the BB shell -- but the same problem exists today, since one can cross-thread a Euro BB. In that cause, we just use American BB instead of Mid. Bonus: American gives us enough room to build an EBB if we want!)

  23. #23
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by El Caballo
    Preload is adjusted by moving the crankarms -- just like moving the stem to adjust bearing play on a headset.

    My question to you: how would *you* construct the crank/frame interface? What are the problems that none of the existing designs address, and how would you solve them?

    (I like American and Mid BB because they're so heinously simple and cheap. No buying "bottom brackets", just standard size replacement bearings available from any number of industrial supply places. Want to go deluxe and get tapered roller bearings? Buy them yourself and avoid the extra markup of a bike parts manufacturer, distributor, and retailer selling you the same things in a threaded enclosure. The only argument I see against this is that ham-fisted folks could damage the BB shell -- but the same problem exists today, since one can cross-thread a Euro BB. In that cause, we just use American BB instead of Mid. Bonus: American gives us enough room to build an EBB if we want!)

    The above design except with a larger BB shell for larger bearings and a different spindle/crank spline. No pinch bolts on the arms. The adjustable cup is the key.
    mtbtires.com
    The trouble with common sense is it is no longer common

  24. #24
    the goose is loose!
    Reputation: rm_racer's Avatar
    Join Date
    Feb 2006
    Posts
    1,276
    or, my dad and i were talking about this a few weeks ago: to improve upon the outboard style bbs, use a tapered bearing like my motorcycle's headset. the set a preload torque and be done. most if not all of the outboard systems require some type of side-load to prevent play. tapered bearings are designed for that. put some tapered bearings in the bb cups, and then screw on a preload ring like the 07 shimano, (but this will have a higher torque), then have a press-on left side crank arm (again, like 07 xtr and truvativ) and it presses against that preload nut. the same way isis arms press against the pressed-on spacer between the arm and the bearing. it's like a motorcycle headset but with crank arms on the spindle, not triple clamps. the bearings are also pretty easy to clean and service. and all you do is replace the bearings if something needs replaced.

    or, an improvement on that, have races in the bb shell, the bearings ride on those races, the right-side arm's spindle goes through, tighten the preload nut, press on the left arm, done. like the spanish interface, but with tapered bearings. but, you's have to seal it somehow.

  25. #25
    mtbr member
    Reputation: itsdoable's Avatar
    Join Date
    Jan 2004
    Posts
    1,902
    I agree, adjustable cups are nice - but I'd still want the pinch bolt. An interference fit (taper or pinch) between the crank & BB spindle is much less prone to creaks.

    Better yet, loose or caged bearings with the race ground directly on the BB spindle would be better... but hasn't that's been done?

    Quote Originally Posted by El Caballo
    ...My question to you: how would *you* construct the crank/frame interface? What are the problems that none of the existing designs address, and how would you solve them?...
    I actually don't have a problem with Shimano's External bearing system, what "problems" are not being address? The cartridges bearings are easily replaced by off the shelf units, although I would recommend re-packing the grease in the standard bearings before using them on BB's.

  26. #26
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by itsdoable
    I agree, adjustable cups are nice - but I'd still want the pinch bolt. An interference fit (taper or pinch) between the crank & BB spindle is much less prone to creaks.

    Better yet, loose or caged bearings with the race ground directly on the BB spindle would be better... but hasn't that's been done?
    I would still prefer and use square taper if I could and loose ball BBs. The only reason I use the pictured BB is I can not get a reasonably priced square taper crank longer than 180mm.
    mtbtires.com
    The trouble with common sense is it is no longer common

  27. #27
    otb club member
    Reputation: Chris2fur's Avatar
    Join Date
    Jan 2004
    Posts
    2,726
    Quote Originally Posted by itsdoable
    I actually don't have a problem with Shimano's External bearing system, what "problems" are not being address?
    The biggest weakness to me is the plastic end cap/axle shim system. First of all, it's not a great sealing system because there is no seal at the axle. Secondly, it really puts a drag on the system. The old sealed bottom bracket assemblies are noticably smoother. Our replacement bearing kit addresses these shortcomings by providing bearings with a smaller ID to match the axle, ditching the plastic end caps and repacing them with a seal that rotates with the axle and has light contact with the outer sealing edge of the cup. An added bonus of the smaller ID on the bearings is that it allows room for larger balls in the cartridge bearings, making them stronger.
    Attached Images Attached Images

  28. #28
    mtbr member
    Reputation:
    Join Date
    Sep 2006
    Posts
    857
    As a person learning all of this stuff, threads like this are awesome.

    I do have one question, are these newer style BB's designed with durability in rain/mud in mind or is it all just strictly strength?

  29. #29
    mtbr member
    Reputation:
    Join Date
    Dec 2003
    Posts
    2,977
    Quote Originally Posted by MillerSHO
    As a person learning all of this stuff, threads like this are awesome.

    I do have one question, are these newer style BB's designed with durability in rain/mud in mind or is it all just strictly strength?
    I think they wanted a bigger spindle to increase stiffness and reduce weight. They needed bigger bearings to get back the durability we once had with the old square taper BB. I don't think mud/rain had much to do with it as they (isis/octo BB) were not lasting as long as the old square tapered BB in normal conditions.

    The complaints about rain/mud performance i really don't get. Did we have the same problems with the 6803/6903-2rs bearings we used in our squared tapered BBs? Although i will admit most of mine were 4 bearing set ups and lasted a very long time with zero maintenance

  30. #30
    mtbr member
    Reputation: itsdoable's Avatar
    Join Date
    Jan 2004
    Posts
    1,902
    Quote Originally Posted by Chris2fur
    The biggest weakness to me is the plastic end cap/axle shim system. First of all, it's not a great sealing system because there is no seal at the axle....
    The HollowTech-II systems have a tiny o-ring on the axle that the instructions warn you not to loose, or forget to install. It seals the axle at the end cap and crank arm - it seems to work pretty well. But that is not to say that your system isn't just as good (if not better!).

  31. #31
    Blanco
    Reputation:
    Join Date
    Nov 2004
    Posts
    1,332
    Ratt has it right.

    Square taper worked well for decades, but some people complained that they could flex the BB and they needed a stronger spindle. (Whether this is the BB spindle flexing, or their frame flexing at the BB, is open to question.) Also it was possible to get creaks over time if the square hole on your cranks rounded out a little.

    Also, component manufacturers are always looking for some new way to make a part so they can sell us "new and improved".

    In addition to using splines instead of a square, Octalink and ISIS both use a larger spindle for added stiffness (and reduced weight). The problem is that BB shells didn't get any bigger, so the bearings had to get smaller. Smaller bearings wear out much more quickly...thus the durability problems.

    External bearings solve this problem by moving the bearing cups outside the BB shell, so they can be larger. This, however, has its own set of problems, many of which have come up in the discussion.

    The right solution is obviously to have a larger BB shell so that larger bearings and a larger axle can both be used without all the contamination and fitment problems of external bearings. But then you're not directly compatible with older frames.

    Personally, I don't think this is a big deal. It's easy to make a Euro (standard threaded) BB adapter for any of the other, larger standards. Here's an idea: just go to EBB shells for everything. Want to use an old-style regular BB, inboard or outboard? Use the EBB cups. Want the lightest BB possible? Adapter cups for Spanish or Mid BB would be trivial. This seems like it would solve everyone's problems.

  32. #32
    mtbr member
    Reputation: itsdoable's Avatar
    Join Date
    Jan 2004
    Posts
    1,902
    Also, one of the biggest advantages of the spline BB interface was to manufacturers and mechanics. With a hard stop on the spline, it became a lot easier to spec the bike and get the correct chain-line - square tapers always varied in chain-line depending on which manufacture you picked, and often within a manufacturers. Also the hard-stop also prevented ham-fisted wrenches from destroying the taper by over tightening it, which was pretty easy on lower end cranks made from softer aluminium alloys - but they found many other ways to bugger up the spline installation.

    Most of my bikes still have square taper BB's, they last a long time if you take care of them. But I do notice that the larger spline BB axles are stiffer - but it probably does not make much difference to my ride. I have no issues switching to the Shimano External bearing system - I just don't need to yet.

    re: using eBB shells - unfortunately there is no standard ID for eBB shells, everyone's eBB insert is a different diameter.

  33. #33
    otb club member
    Reputation: Chris2fur's Avatar
    Join Date
    Jan 2004
    Posts
    2,726
    Quote Originally Posted by itsdoable
    The HollowTech-II systems have a tiny o-ring on the axle that the instructions warn you not to loose, or forget to install. It seals the axle at the end cap and crank arm - it seems to work pretty well. But that is not to say that your system isn't just as good (if not better!).
    Yes, good point. The O-ring is a seal, but it just barely qualifies. The real complaint I have with the OE system is the sealing is not so great, yet the friction is relatively high.

Members who have read this thread: 1

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.