ISIS Bottom Brackets

BXC-600

When we took over the distribution of SKF bottom brackets, we didn’t have high expectations for the ISIS bottom brackets. We were surprised when they became one of our more popular products. We sell them to customers who haven’t heard of Bicycle Quarterly, supple tires or any of the other things that we usually are associated with.

ISIS was an “open source” standard developed by a few of small makers – including Race Face and Truvativ – to counter Shimano’s proprietary Octalink interface. Shimano discontinued Octalink when the company began to attach the spindle to the right crankarm. Other companies followed suit, leaving ISIS as an orphaned standard.

ISIS made sense in theory, with a splined and tapered interface, but in practice, the large-diameter spindle left too little space for the bearings inside the standard BB shell. Most ISIS bottom brackets last only a few months in hard use.

SKFBB_Exploded

SKF got around this problem by running the bearings directly on the spindle and shell, which allows the use of much larger bearings. The drive-side bearings are roller bearings, which have very high load ratings. In fact, the bearings of SKF’s ISIS bottom brackets are exactly the same as those of their indestructible square taper bottom brackets.

In an odd twist of fate, we ended up with the only reliable ISIS bottom bracket on the planet. Instead of replacing bottom brackets after just a few months of service, riders now can rest assured that our 10-year warranty on SKF bottom brackets includes the bearings. If you have a cherished ISIS crank, these bottom brackets allow you to extend its lifespan for at least another decade. Most likely, this will be the last ISIS bottom bracket you’ll ever have to buy.

I am almost tempted to offer the René Herse cranks with an ISIS splined interface, now that there are reliable ISIS bottom brackets…

Click here for more information on SKF bottom brackets.

About Jan Heine, Editor, Bicycle Quarterly

Spirited rides that zig-zag across mountain ranges. Bicycle Quarterly magazine and its sister company, Compass Cycles, that turns our research into high-performance components for real-world riders.
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22 Responses to ISIS Bottom Brackets

  1. Paul says:

    I tell people all day long at my shop that “new” is not a synonym for “better”. Thanks for solving problems instead of creating “new” ones.

  2. David Feldman says:

    No, Jan, please DON’T ofer ISIS RH cranks!

  3. Patrick says:

    Not compatible with Shimano Octalink right? (I have an old pair of Shimano Deore XTs with Octalink and fear wrecking the only BB I have, but I guess when that happens, it’s time for new cranks).

    • Octalink is a patented, proprietary standard, and only Shimano is allowed to make BBs for that…

      • Octalink seems to hold up pretty well; I had a set of Ultegra double cranks running on a 105 BB for many years; they moved from frame to frame and I finally sold them–along with the BB–when I went to compact double. Are the bearings appreciably different?

      • The standard Shimano cartridges last remarkably well for such an inexpensive part. However, the bearings aren’t nearly the same quality, nor as well-sealed as the SKF.

      • That’s probably so; I was thinking more of the significant difference between the reported life of non-SKF Isis parts and the Shimano Octalink. I have had amazingly good results with Shimano BBs generally, but in this case–since Isis was sold as a kind of boutique part in the first place–I’m really curious as to what they did wrong.

      • What they did wrong with ISIS is increase the spindle diameter so much that with normal cartridge bearings, there isn’t enough room for decent bearings. The SKF gets around that by running the bearings directly on the spindle and on the shell, thus saving the space that other BBs require when they press the bearings with separate races onto the spindle and into the shell.

  4. David Pearce says:

    What was the purpose of ISIS? Why is it better? The bigger spindle, less twist? But right now there is some other standard used now by the biggies, with bearings outside the bottom bracket shell, or I’m not sure? I can’t keep it all in my head.

    Perhaps a little history–only a little–of various standards would be good for an upcoming issue of BQ. When I was assembling my bike, Green Hornet, my mind just boggled at how to match up the various pieces, and I’ve forgotten it all now. I have a used Campagnolo Veloce triple 9-speed crank mated to a new Campy bottom bracket (I think it’s 121mm).

    I can see that my legs just aren’t going to be able to do loaded touring without lower gears, and my “gruppo” is getting to be & going to be less and less of a group: Already I’ve abandoned the Veloce dual pivot side-pull brakes for the VO Zeste cantilevers, and I’m already at the lowest gearing I can get for this setup, 32-tooth small front ring, and replaced the rear 13-28 sprockets that came with my eBay purchase with the 14-30-tooth model. And you know the rest of the story, the ramped chainrings, can’t get any smaller rings, this chain won’t work with those gears, etc., etc. It’s enough to make one’s head explode….. My unused parts bin is getting awfully large…… But I am keeping calm.

    So I assume when the time comes available that I can do some light touring, I will no doubt get your René Herse triple, and probably the SKF bottom bracket to go with it, and if I need to change the front derailleur, I’ll do that too, although I think it looks like it might be smooth enough to shift RH chainrings. Can you say, will a c. 1998 Veloce triple 9-speed front derailleur work properly with RH chainrings?

    • ISIS isn’t really better than square taper – otherwise, we wouldn’t have made a square taper bottom bracket. The spindle is a bit bigger, which allows thinner walls and thus lighter weight, but if you were using a minimalist aluminum crank like the René Herse, you’d need more material to accomodate the bigger spindle… You’d gain little and you’d be locked into an obsolete standard.

      As to the new one-piece crank/bearing assemblies, at least the bearings are easy to replace, since they rarely last well…

      As to the Herse crank with your Veloce triple, if it has a smooth inner cage, it’ll be fine.

    • Fred Blasdel says:

      The purpose of ISIS was that square taper spindles did not hold up to hard MTB use at all, it was common to have your cranks spin independently or have an arm fall off. Dedicated gravity riders could use tubular cromoly splined cranks adapted from BMX, but the weight and anklebiting Q-factor made them unsuitable for anyone else.

      Since the 2-piece design took over ten years ago, even the most abusive riders can use normal cranks and failure rates have all but disappeared — even on cheap stuff that wasn’t made with anywhere near Jan’s attention to detail

      • Fred, thank you for providing that perspective. Obviously, I am not too concerned about downhill mountain biking. Even though I like to ride off-pavement, I am still a road rider…

      • Conrad says:

        I’m not really too familiar with dedicated gravity riding but I would be surprised if an ISIS setup stayed in place better than a properly installed square taper. When I had an ISIS setup, I did have to occasionally re-tighten the crank bolts. I never have to do that with a square taper. I quit using ISIS stuff because the bottom brackets available at the time didn’t last too long. I had always thought that the square taper was replaced for a perceived lack of stiffness… but if this is the case, then why is it still the standard on the track? If it isn’t a problem for match sprinters or keirin racers, I guess it shouldn’t be for anyone else, right?

      • There still is a lot of talk about stiffness, but in reality, many track races actually prefer frames (and perhaps components) with some give. This was perhaps the most interesting part of our discussions with various Keirin framebuilders in Japan.

      • Benz says:

        Not to be a cynic, but the ISIS standard was invented to counter Shimano’s proprietary Octalink standard. Valid as the design’s intended use was, there weren’t too many “extreme” MTB users to warrant the investment of creating a new BB standard; but something had to be done to mitigate the perception of being “left behind” by Octalink, unless one would pay the licensing fee (like Sugino, for instance). Ironically, Octalink itself was an unwanted standard by most cyclists, since folks were fine with the square taper standard, despite its shortcomings. My commuter with square taper cranks has seen seasons of (admittedly mild) Californian winters and doesn’t seem worse for wear and this is with a relatively cheap UN-55.

        It is also a bit disheartening to remember those as the “good old days”. Nowadays, there are more BB standards than one can shake a stick at, none of which really addresses a real problem for most cyclists, only perceived problems of “looking pro”, having “stiffness”, or “keeping up with the jones”.

        I’ll go back into my retrogrouch box now…

      • I totally agree – that is why our René Herse cranks use a square taper. It’s still the best solution for most applications.

        However, for those riders who have an ISIS crank and cannot find a bottom bracket that lasts more than 6 months, it’s nice that the SKF units are available.

    • Jon in SF says:

      This is the best summary of the evolution of the different types of bottom brackets that I have seen: http://www.bikeradar.com/us/gear/article/complete-guide-to-bottom-brackets-36660/

  5. neil says:

    Just an FYI that the Octalink bb is not discontinued. Shimano still uses it on some entry level hybrid and road cranks, the Alivio and Claris respectively. Bearing quality and longevity has not changed and still manages to disappoint.

    • Charlie says:

      It’s as if Shimano is stubbornly determined to win the now-irrelevant 3 piece splined crank battle. Most OEMs that spec those groups use different cranks anyways.

  6. Scott G. says:

    David, I have it on good authority the new RH cranks are cottered.

    • I get the joke! It’s doubly funny because Herse was one of the first makers to offer a crank that was not cottered, way back in 1938.

      Herse cranks and other parts we offer are not about nostalgia or retro, but simply the best parts for the job. I am dreaming of offering a carbon-fiber part, I just haven’t found a cycling application where carbon is the best material for the job. So for now, it’s aluminum and steel, but I am not opposed to other materials, as long as they offer better performance.

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