I like rigid MTB.
Is Octalink still a good system when comparing to the modern external BB ?
Is Octalink a good system ?
What are its weaknesses ?
1) Smaller bearings than outboard/large bearing system, like BB30 (though this isn't, strictly speaking, always true) means slightly quicker wear and less overall durability. Again, take this with a grain of salt, as it's not always true.
2) The axles in outboard/large bearing systems tend to be larger, ergo, stiffer. This may or may not be a problem for you.
3) The chainline on an outboard system is easier to change, within the confines of the axle length.
Other than those points, an external bottom bracket offers no real 'advantage' so to speak. Internal brackets are better sealed and better protected, so often serve better on utility bikes, but also work well on sport bikes.
Octalink and ISIS splines work very well in terms of securing crank arms, and tend to be cheaper to boot. In my mind, if you can get a good deal on something, run with it, rather than worrying about what you have or what to get. If it's already on your bike, feel free to upgrade to an external system when your current stuff dies, but I would not make it a priority.
I run Octalink on my SS, had external on my FS (now square taper) and run external on my HT. I do not notice a dramatic difference in terms of stiffness between the three though the Octalink turned out to be a bit too flexy for my FS. I have less than 3mm clearance on the non-drive side and could hit the chainstay more than occasionally with the crank arm running Octalink (even with spacers). Duddn't flex nearly as much with square taper. My SS has more chainstay clearance so the XTR/Octalink setup works great there
All have been dunked above the BB on rides here and there and continue working silently. The one thing you need to be careful of with Octalink is making sure the cranks seat correctly on the spindle before tightening.
Octalink was a pretty solid system. But at this point it's pretty dated no reason to search out the parts for a build. I'd say it's worth keeping it alive though. BB's will be around for a long time. I don't know of anybody that's still making cranks in octalink or ISIS though.
Middleburn in the UK still produces cranks for the Octalink (and square-taper) bottom brackets.
There's no way I'd ever go back to an Octalink. External bottom brackets are a brilliant design that improves rigidity and saves weight.
Middleburn makes ISIS cranks, not Octalink. Shimano still makes Octalink cranks though.
I think PF30 or BB30 is the way to go, even better and more flexible than standard shells with external bearings.
Former bicycle mechanic for 8 years, current soil scientist.
Yes, that's what I wrote, but my Shimano phone auto-corrected ISIS to Octalink.
Originally Posted by Bike Whisperer
really it's weight and a few other things all minor on their own but add them all together and there are nice advantages to a modern BB,... the externals are lighter and also easier to clean. I do find the externals I find actually get dirty faster as they are more exposed, at least with regular threaded ones, haven't played with press in much.
External are stiffer, thou the average person wont notice the diff. there are more plus's and minus but the external +'s way out weight the -'s
But, honestly, if you have issues with you BB but cranks and rings are fine, just keep the Octlink. if cranks are work, BB is toast or close, and/or rings are worn, you basically need a whole new everything, then go with a more modern setup...