Is ISIS going to become Obsolete?

Recently I have entered two bike shops after more than a year of not visiting them. I was interested to see that very few of the bikes being sold have ISIS cranks! I did not have time to look intothe mater more but the owner of the first shop said that ISIS is already Passe! could this be? What is the dominant competitor to ISIS other than than Shimano’s Octalink?


I thought that octalink was dead but then I have mostly been going into bike shops for seat post clamps, tires, tubes, spokes, and good company.

I think ISIS will live on for some time on unicycle hubs because it’s much more suitable for them than it is for bikes.

Most good new bike cranks now have the axle permanently attached to at least one of the cranks, which would not really work on a unicycle. Campagnolo cranks have half the axle attached to each crank, and join together with a sort of castellated dog clutch arrangement in the middle. I think Shimano has the whole axle attached to the right crank and an ugly pinch bolt to hold the left one on (like the old steel KH splined cranks).

ISIS didn’t really work very well on bikes because the thicker axle (than square taper) meant that the bearings ended up being very small to fit inside the standard bottom bracket shell. ISIS bottom brackets eat bearings in no time. People tried to “cure” this problem by moving the bearings outside the bottom bracket shell, but by then other interfaces had already pretty much taken over.


square taper works fine for most bikes, they don’t take the kind of abuse that a uni crank and hub will take.

another unique thing about isis is that it’s open source!

I thought Octalink was dead years ago.

The problem is that for the past few years the big bike companies have been introducing more and more proprietary bearing sizes as part of a marketing fad advertising “stiffer” “beefier” &c components. This locks customers in and eventually forces obsolescence, but the differences are too small to be really noticeable. Most cyclists can’t tell the difference between the good old standard square taper cranks and whichever proprietary one their favorite brand is selling this year. So there is no dominant competitor.

I think ISIS will stay the best option for unicycles indefinitely. Unicycles benefit more from splined cranks than bicycles do. If you are only pedaling forward, a tapered crank is fine, but back pedaling wears a tapered crank “quickly”. (I put “quickly” in quotes because the cranks on my mountain bike are still usable after fourteen years and thousands of miles. My last road bike was 23 years old when I sold it, and it still had the cranks and bottom bracket that the original owner bought, and they were in excellent condition with many thousands of miles.) ISIS cranks are supposed to last much longer when pedaling both forward and backward. The unicycle market isn’t big enough to justify all the silly extra crank designs seen in bikes these days, so it makes sense to stick with ISIS.

You could put it that way, because Shimano patented the splined design of the octalink, and so ISIS was put on the public domain

I agree that square taper works perfectly well on bikes - in fact the only bike I’ve ever had real crank or BB problems with is my winter commuter with a splined BB (almost ISIS but not quite the same). Every other bike I’ve had or still have is square taper (apart from a few cottered ones before my teens when cotterless became the norm) and worked perfectly, on road and mountain bikes.

My unicycles are now all ISIS apart from my 20" learner/freestyle, but only really because that’s what’s easier to get now. I think unicycle axles do take more force than bike BBs, but I never broke a square-taper axle or had problems with loose cranks on my previous muni or 36er. I think unless you ride big drops all the time (or possibly do a lot of hopping) then even ISIS is a bit overkill. But on the other hand it’s nice to know it’s stronger than it needs to be.


2/3 square-taper unis I’ve owned have had frequent problems with cranks coming loose, and the other one just less-so; still came loose some times.

I did my cross-Canada tour on square taper. I got a loose crank about once every 900 km, on both the original 150s, and the fresh 125s I installed after the mountains. The hub was brand new before leaving (necessarily - thanks to Darren!). Maybe I wasn’t putting them on tight enough? I was putting everything I had into it, including hammering them on first when I could.

ISIS is the most important new feature after my T-Bar on my new KH. About 1000km and no problems yet. Looking forward to riding a tour later this summer without having to lug around a crank extractor!

If ISIS goes away I’ll be sad. But I don’t think it will - it’s a standard borrowed from bicycles, but now many parts are available made-for-uni. Even if everyone in the bicycle world gives up on them, it’s so valuable for unis that I think they’ll still be made for us. Other than square-taper, we’re rather short on options.

no way, isis is the best.

ISIS may be the best thing the bike industry gave to unicycles. It may very well go obsolete for bikes. It’s naive to think that any of the companies churning out cranks are going to tool up for something unique to unicycles; however, they are already set for ISIS. So if the interface goes extinct in the bike realm we already have the cost benefit of large manufacturers ready to supply us.

We’ll see what happens, but I expect ISIS to be around on uni’s for quite a while. Even the new Torkers are using it.

its may come down to cost too… just by the look of it… ISIS Cranks are just a more difficult to machine. verses the octalink which just seems to take a straight groove right out of the metal.

I’m pretty sure the Octalink isn’t tapered, which in my opinion is very important for preventing looseness and fretting.

Sorry to burst your bubble, but it really really isn’t. Maybe in unicycling, but that’s still up for competitive debate.

A guy who’s main forte is DH/FR mountain biking may be able to offer better insight than I, but the general consensus is that ISIS is quickly becoming the standard on all bikes that take Euro bottom brackets (i.e. almost all the standard cheap commuters and entry level MTBs).

Square taper is the one that is dying out. Fastish.

For higher end MTBs, ISIS is not the best. DH/FR bikes have a few crazy strong interface systems, which are very expensive, but do the job way better than ISIS in many cases. The ISIS spindle itself is OK, but not indestructible. But I will give it one serious merit: simplicity. Dead simple to get cranks on and off, and it’s very much fit and forget.

Trials bikes still use ISIS, but it’s not really strong enough for a lot of riders. It’ll do though.

I don’t see ISIS being a problem for unicycle riders anytime in the near future. I have not heard of a lot of problems with ISIS axle/crank strength.

The only problem that is common is the one involving the flanges of the KH hub, which has been resolved in the newer hubs.

I may not be very heavy, but i have thoroughly abused my axle and Cranks and had no issues with strength of the ISIS interface… just the flanges and drilled rims.