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Square Taper Vs Isis


ghosts_cloak

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Hey guys, what do you recon, square taper vs ISIS crankset. This is the option I have for my Leeson.

Mr Leeson himself stated that in his opinion a very tightly wound on square taper crank is superior to ISIS. I believe him as he certainly knows about bikes and engineering. However this is the first time I had heard this!

Previous to speaking to Mr Leeson I was sure that square taper was being phased out and had no future.

The crankset in question will be a Middlesburn pro trials set, opinions?

~Gareth

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The problem with ISIS is that the axle is bigger, therefore the bearings used in the BB are smaller, therefore not as strong.

However Square tapers round...

It's pretty much a 6 of one, half a dozen of the other situation...

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The problem with ISIS is that the axle is bigger, therefore the bearings used in the BB are smaller, therefore not as strong.

However Square tapers round...

It's pretty much a 6 of one, half a dozen of the other situation...

I prefer ISIS, as for the reaon metioned above, they don't round. They also have a stiffer feel aswel.

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I say square too,

i've never had any problems with square taper, and anyone who looks after their bike never should have a problem with them.

Just check you crank bolts are tight frequently and its all good. :)

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id go for isis for the reason thats this: if your round of your square taper cranks then your 120 guid down, but on the other hand you buy isis, the bottom bracket bearings is the weak spot so if it goes its a new bb but the taper on the cranks will be fine so just get a new bb for around 30-40quid, isis are also stiffer which is useful in trials

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I have never had problem with Square tapper , except maby once when i couldnt get my crank arm off!

i have though, seen 2 people had the crank bolt on there isis snap or round off, resulting in the arm falling off!

Are isis cranks susposed to tighten up to the axel like the square taper? requiring a crank arm tool to remove? or does the bolt its self clamp the arm?

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i went through 5 or 6 sets of inferior square taper cranks rounding them all off, before buying isis middleburns.never had a problem since (3 yrs and counting) with either the cranks or the bb axel or bearings.i have ridden once or twice with loose (read falling out) crank bolts by mistake with no probs at all, something i dont think i could ever get away with with sq taper.

does that show the quality of isis or middleburns, im not sure.....?

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I have had about 3 piars a ST cranks and i have rounded one piar of becuase i was riding with them loose and i dent notice it was. I have had 1 isis cranks on my DH bike and nothing has been wrong with them.

I would prob choses ST but just keep them tight with locknut and in good conition.

:turned:

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With quality cranks like middleburn you should never ever have a problem with them rounding off.

I would go with square taper because I have only ever broken two axels in 5 years and the bb's are cheap and last ages and ages and ages and....

I think you would only ever have a problem with square taper if you take your crank arms off twice a month or something like that.

I personaly dont know, but can you actually tell the difference in stiffness between middleburn square and middleburn isis??

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Surely if the isis axels are bigger and the bb bearings need to be smaller, then there are more bearing and a larger contact area, meaning a stronger bearing? I'm a civil engineer btw, so I think like this all the time.

I have rounded a few pairs of st cranks, although never had a problem with my Middleburn RS1s which are still perfect (yes, RS1s!)

I would go with isis though, clearly a better system imho, which is why my new RS7s are isis.

Edited by MikeWarner
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I've had square tapered bottom brackets with middleburns and never had a problem apart from cracking every now and again, but its only a standard onza bottom bracket

But with my mates olie and beau they have had isis middleburns using a truvativ bottom bracket and both have screwed it up :turned: , but every since the invested in an expensive bottom bracket (koxx one) they haven't had a problem. :D

So my advice is if you want an isis crank spend abit more than you would normally on a bottom bracket and you should be fine, but if you aren't that bothered about square tapered bottom brackets rounding go for square taper. (i have seen a rounded middleburn squared taper and its not a nice site)go for square taper

Edited by onza_tom123
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Good morning guys :D

Wow lots of thoughts on this topic! A good mix of opinions too! Hmm I think that the majority are chanting "ISIS!", but as people have mentioned if you just put ST cranks on tight and leave them on they should be fine. The only time I would remove the crankarms would be to change the BB...

The cost savings, the fact I would rarely take them off and Im not much into big drops, are all prompting me to take the square tapers :turned:

Cheers,

~Gareth

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Imo, neither are great. I think that Octalink is the best interface as it is a compromise between the two, it has a larger axle than square taper with a splined interface, so it doesn't round but the axle isn't as big as with ISIS so the bearings are still reliable. The only problem being that you are very limited in arm choice, especially with 5 arm spiders.

The other option is an external BB, like the RaceFace X-type cranksets, because the bearings are large and you still get a large axle and a splined interface. However you may damage the left hand BB cup doing trials as it is external and therefor exposed.

I'd just stick with square taper as long as its good quality stuff. (poor cranks will round and poor BB will snap in half very painfully :turned: ).

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im gonna say isis due to the larger veriety of bb sizes avaliable (try finding a 73 x 127 square taper bb :turned: )

super splines, like on 3 peice cranks work well, they dont have a mahoosive axel, the bearings are good, they just weigh a tonne.

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Well I can tell you as I have both SQ Burns and ISIS Burns.

The SQs are damn good, strong, light, pimp

The ISISs are also damn good, strong, light, pimp BUT also stiffer. They just feel slightly stiffer that the SQs.

Also if your isis bolt comes loose on a ride, you wont round your cranks off :turned:

The isis BBs tend to be a little more expensive but its worth it :D I've had my raceface SRX (£30) for two years now with no problems.

Sam

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I have always used taper for trials...however I have another bike which uses Isis, some Truvative Blaze crankset... Isis does not have any particualrly large noticable difference in stiffness compared to taper if done up well... I have had goes on other people's bikes who have Isis... I feel no real stiffness difference between Isis and taper... so long as taper is kept tight and well looked after... it is very good....

Taper is perfectly fine as long as it is watched after... Only problem about Isis is that it is so damn expensive compared to Taper... if you're after a decent set up.... But the arrival of 2005 Isis Echo cranks at only £55 is a bargain :D.... Most other decent Isis cranks were around the £100 mark until Echo came along :turned:

I also read somewhere in a Mountain biking book 2005... in Halfords that Isis, in a few years would take over and be on any old standard bike.... kind of like the DVD-Video situation....

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sqaure taper anyday for me, ive used isis, and to be quite honset i couldnt tell the difference in feel, although if sqaure taper is 'looked after' correctly you should haveno problems...................

probably one of the better designs is the new hollowtech 2 designs from shimano, the only downside to this being the bb cups on the outside of the shell, i wouldnt like to sidehop onto one................

square taper

ash

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