# Aerozine cranks



## Tiffster (Jan 30, 2008)

Just seen these cranks from a UK website - 735grams complete with STEEL bolts so swapping to Alloy's would put it around 725g complete - not bad for the price!

http://www.superstarcomponents.com/CranksProductSLTi.html


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## DeeEight (Jan 13, 2004)

I wonder which "grade 5" titanium they're referring to for the spindle. They're lying about the maintaining the stiffness though... just like for square taper before it, if the bearings are the limiting factor in axle diameters, swapping out to the same diameter axle in a material 2/3 as stiff.... well....


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## Tiffster (Jan 30, 2008)

Well if its grade 5 id imagine it would be 6Al-4V ti which would be more than tough enough. Im not sure using a Ti axel would do anything to stiffness - increase or decrease as you have the bearings at each end fixing it in place so its not going to flex....


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## cmh (Jan 30, 2004)

DeeEight said:


> I wonder which "grade 5" titanium they're referring to for the spindle. They're lying about the maintaining the stiffness though... just like for square taper before it, if the bearings are the limiting factor in axle diameters, swapping out to the same diameter axle in a material 2/3 as stiff.... well....


It's hollow, so you can still modify the ID to modify to control stiffness, just to a lesser degree than controlling OD. Plus, thanks to the wide support of the external bearings, there is very little unsupported axle length as there was in the old square taper.


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## petercarm (Nov 5, 2007)

cmh said:


> It's hollow, so you can still modify the ID to modify to control stiffness, just to a lesser degree than controlling OD. Plus, thanks to the wide support of the external bearings, there is very little unsupported axle length as there was in the old square taper.


In which case there would be no weight advantage.


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## cmh (Jan 30, 2004)

petercarm said:


> In which case there would be no weight advantage.


All depends on the ID that's chosen... you might be able to get a *comparable* stiffness with ti without using too much material and giving up the weight advantage.

Considering ti spindles were available in square taper (and even some in ISIS) I was surprised that not more high end weightweenie cranks didn't use ti for the BB spindle. Hasn't Cannondale used aluminum spindles in their road bikes, albeit with a proprietary BB shell?


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## DeeEight (Jan 13, 2004)

Tiffster said:


> Well if its grade 5 id imagine it would be 6Al-4V ti which would be more than tough enough. Im not sure using a Ti axel would do anything to stiffness - increase or decrease as you have the bearings at each end fixing it in place so its not going to flex....


For the same dimensions, it'd reduce the stiffness. Its no different than again in the square-taper days, Ti BB spindles FLEXED more than steel ones. Which is why shimano never offered a Ti square-taper BB and why they invented Octalink in the first place. They needed a way to compete with the aftermarket Ti BB market (as resales of the high end XTR square-taper BBs were, well, stagnant to put it mildly) in terms of weight without the stiffness suffering. Which is why we got the M950 BB, which at 177g for a 116mm E-type FD compatible, dual 68/73 shell compatible, hollow CrMo spindle BB is damn freaking light. I just put one in my LiTech build (which is how I know its 177g) yesterday as it happens. The things basically never wear out and are completely rebuildable. They used wide caged roller bearings to handle vertical loads and small caged ball bearings right next to them to handle lateral loads (inboard from the roller bearings).


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## DeeEight (Jan 13, 2004)

cmh said:


> It's hollow, so you can still modify the ID to modify to control stiffness, just to a lesser degree than controlling OD. Plus, thanks to the wide support of the external bearings, there is very little unsupported axle length as there was in the old square taper.


You'd have to increase the thickness significantly to make up for the nearly 40% reduction in stiffness from the steel spindle, which mitigates the weight savings and from the photos, it doesn't look appreciably thicker anyway. As to the bearings... there basically is ZERO difference between unsupported axle length compared to square-tapers. The unsupported axle is everything outboard of the bearing... and that's only the length needed to hold the crank arm which hasn't really changed in width in the past decade.


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## SmashWings (Jan 4, 2006)

very interesting cranks, similar cranks: Aerozine=Token=Atik=MSC (Ti versions)
But these are slightly cheaper than Token ones (in euros) (Token EX200 on eBay)


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## Toff (Sep 11, 2004)

xxx


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## Ausable (Jan 7, 2006)

They are nice and available in Pink:rockon: :rockon: 
Somebody said they are rather flewxy (cant remember the old thread) but they are light and pretty cheap (steel axle version)


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## crank1979 (Feb 3, 2006)

I've got a pair of the steel bb Aerozines. I just went from 175mm arsm to 170mm but haven't ridden the shorter arms yet. I never noticed any flex in the 175s. I've got them in black because i'm finding it hard to get the pink ones.

If you get a chance to check out the Tokens, Atiks and others that look the same you should find they have "made by Aerozine" or similar on the inside of the arms.


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## Buoyen (Aug 14, 2006)

How is q-factor on those, nino? Is the BB only for 68mm or both 68/73?


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## GRAVELBIKE (Oct 7, 2006)

Buoyen said:


> How is q-factor on those, nino? Is the BB only for 68mm or both 68/73?


I think they claim 165mm on their site.


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## nino (Jan 13, 2004)

Buoyen said:


> How is q-factor on those, nino? Is the BB only for 68mm or both 68/73?


q-factor is 165mm!

they are for 68/73mm BB shells AND also accept E-type derailleur! just like Shimano they come with 3 spacers to adjust to any possible configuration.


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## jtack (Sep 23, 2004)

how much fo the ATIK


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## Cheers! (Jun 26, 2006)

I paid 350 USD for my pair of Atik from http://procyclingdiscount.com/

you need to email Ernie who is the owner of http://procyclingdiscount.com/ as he does not list them on his Ebay store. I believe he is the distributor for Token and Atik in USA (if not he is a major seller for them).

I didn't like the atik crankset, I tried them for more than 1 season. There was no torque spec for any of the bolts. The axle fixing bolt on the non drive side kept on backing out. The pinch bolt would not hold tight. I eventually added Loctite 242 to all the fasteners and torqued them to the Shimano XT specs.

The chain rings shifted poorly and the crank arms flexed a lot. On top of that the spider flexed along with the chainrings too. If you were running the middle ring (32T) on the crankset and had the rear derailleur on the highest tooth count cog (32T or 34T) and you applied a lot of power to sprint up a hill the flex from the crankset sometimes lost engagement with the chain and threw the chain into the 22T chainring.

I sold the bike with the crankset still installed, if I didn't I would've gotten a XTR M960 tor XTR M970 crankset and called it a day.


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## FueLEX8 (May 24, 2008)

so its a NO for this cranks :madman: 
i was looking at the aerozine.. looks promising
good weight,price and not bad looking


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## Cheers! (Jun 26, 2006)

My experience of it, is that it's crap. But your mileage may vary.


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## FueLEX8 (May 24, 2008)

i've seen problems, about that the angle is not 90 or something like that.. but if there are more, why do i want problems?, i tend to train and race on the same bike so there is some miles right there, im planning to race the TransRockies Challenge, so is better to avoid that type of stuff. Thanks for your comments Cheers!


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## FueLEX8 (May 24, 2008)

what crankset you recommend? i think you have experience with a lot of them..


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## Trail_rat (Oct 25, 2006)

from the uk here . Cheers! has highlighted all the issues another mechanic mate of mine found when he looked at the words "ti" "light" and bought. 

Flex , no torques specified (which after alot of enquiry actually have to be very very high) , and that after all that they fall apart mid race ! . Oh and the BBs last less time than the shimano counterparts ...probably with all that flex in the axel


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## Cheers! (Jun 26, 2006)

FueLEX8 said:


> what crankset you recommend? i think you have experience with a lot of them..


FueLEX8,

If you are going to run a 3x9 setup, it is hard to find anything of better performance, reliability, or price than the XTR M970. Sure it's not carbon, it's not the lightest, but it's damn good.

Shop around. Chain Reaction cycles had them for 380 USD a while back. Starbike.com has them for 330 USD (once you remove the VAT tax that exports are not charged, exchange rate and such).

If you are going 2x9 crankset, then that is a completely different story.


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## FueLEX8 (May 24, 2008)

i would like some 2x9, im using a 11-32 casette, what size chainrings should be fine?


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## Cheers! (Jun 26, 2006)

depends on your riding style and terrain.

Personally I have no problems riding a 32T middle ring 3x9 crankset with a 11-32 cassette even on the longest steepest mountain bike trails I come across. 

For my 2x9 I bought a Middleburn RS8 DUO w/ 29/42 chainrings and used an american classic ISIS bottom bracket with 113mm width.

If you can ride a 32T middle ring anywhere anytime, then a 29T or 30T ring and a 42T would work well for a 2x9 setup.


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## Pate (May 30, 2009)

HI, does anyone know a cheap online store for aerozine cranks?
Best regards

Patrick


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## amillmtb (Jun 24, 2005)

Pate said:


> HI, does anyone know a cheap online store for aerozine cranks?
> Best regards
> 
> Patrick


I've seen them on e-bay.


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## sergio_pt (Jan 29, 2007)

still want to buy these cranks after all the qualities ppl have stated?


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## Pate (May 30, 2009)

amillmtb said:


> I've seen them on e-bay.


I know ;-) but ebay is too expensive. i bought some here (cheap):

http://superstar.tibolts.co.uk/index.php?cPath=30&osCsid=0f8fcdd6fa1ed76ee8052c7b81c3ad6c

but they are sold out and don´t get new ones. ebay is much more expensive.

SO WHO KNOWS A CHEAP STORE?


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## Ausable (Jan 7, 2006)

Moosecycles.com had some models on sale but they are out of stock now *DAMN*
A couple of Italian web stores carry the new models but the price is extremely high (270eur!!!)
It's a shame that those cranks are not widely available, and I confirm that the (relatively) cheapest option is abay. If anybody has a better suggestion please post here:thumbsup:


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## Tiffster (Jan 30, 2008)

I know i posted this thread initially, but i would recommend agaisnt buying these, there just utter crap. I rode a set and the flex from the arms was incredible and shifting across the chainrings was terrible. Add to that the left side crank arm fell off mid ride


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## DeeEight (Jan 13, 2004)

The latest version on ebay have gone to a Al7050T6 for the BB axle, which means they'll flex even more than when they used titanium. But they are lighter now as well as including a ceramic bearing BB.


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## speedbiker (Mar 29, 2008)

Pate said:


> I know ;-) but ebay is too expensive. i bought some here (cheap):
> 
> http://superstar.tibolts.co.uk/index.php?cPath=30&osCsid=0f8fcdd6fa1ed76ee8052c7b81c3ad6c
> 
> ...


In this shop I found cheap Aerozine 2009 cranks.
X-12-SL-A3 for 166€ (incl. VAT), cheaper than ebay in every case or the X-12-FX-A3 for 135€, also incl. VAT.


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## vmajor (Oct 1, 2007)

Aluminium alloy is stiffer and lighter than titanium (in general). Other properties are in titanium's favour.

In the hollow crankset axle application, titanium only has advantage over steel, not aluminium alloy.

In the old and flexy square taper system, aluminium alloy would not have been safe due to its tendency to fail as a result of metal fatigue.

Some newer Aerozine cranks come with NDS crank arms that use twin pinch bolts along with the super large center bolt. This is the best NDS arm retention system that I have come across in two piece cranks.

Also, if you are wondering, Aerozine is the actual manufacturer.

V.


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## DeeEight (Jan 13, 2004)

vmajor said:


> Aluminium alloy is stiffer and lighter than titanium (in general). Other properties are in titanium's favour.


BZZZZZZZZZZZZZZZZTTTTTTT WRONG! But thanks for playing....

(or put another way, exactly what brand of crack have you been smoking?)

There is NO aluminium alloy other than some of the metal-matrix composite ones which are stiffer than any grade of titanium (commercially pure or an alloy thereof) used in structural applications. You're obviously confusing a materials stiffness to weight ratio with its actual stiffness. Al frames are built stiffer than titanium frames (and lighter) because they use oversized tube diameters with very thin tube walls. But they're not doing that because they want to, they're doing it because they HAVE to. Al fatigues faster than just about every other structural material there is, and unlike Magnesium, Iron, and Titanium alloys... Al doesn't have definable fatigue limit (a point where if the load is kept below, there isn't a danger of a fatigue failure). So to make them last, they have to build them to resist flexing. Titanium has no such problem (nor does steel, Magnesium or carbon fiber) and so they merely need to be stiff enough to not flex unduly under a rider's weight.



> In the hollow crankset axle application, titanium only has advantage over steel, not aluminium alloy.


Maybe if you made the axle with a VERY thick tubewall it'd have an advantage, but doing so would quickly eliminate any potential weight savings. Aluminium for a given dimension of part, is about 2/3 as stiff as titanium, which is itself about 2/3 as stiff as steel. The ratios on mass are almost the same oddly enough. On strength however, the titanium and steel alloys move ahead of aluminium. The only reason some parts on bikes are made in Al is not because its the stiffest or strongest material for the job, but because its adequately stiff/strong enough to do that particular job. But to get it to be BETTER than what's possible in steel or Ti, you need to throw a lot more material into it, or a lot more money for the R&D, manufacturing and alloys involved. Thomson stems are very strong, reasonably priced (for the higher end mtb stem market) but not very light (especially in light of their price).



> In the old and flexy square taper system, aluminium alloy would not have been safe due to its tendency to fail as a result of metal fatigue.


Ok so you know about the concept of metal fatigue but nothing about the metal properties themselves.


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## vmajor (Oct 1, 2007)

...the interweb is strong with this one.

Read:

http://www.efunda.com/materials/all...ge_Title= Metal Alloys Keyword Search Results

http://www.efunda.com/materials/all...ge_Title= Metal Alloys Keyword Search Results

I have no time to provide links explaining what that T6 stands for after 7050. It affects the "stifness", but of course has no impact on weight.

Cheers,

V.


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## civil (Feb 13, 2008)

vmajor said:


> ...the interweb is strong with this one.


Not sure what point of yours you are trying to support with these links, but they show that Ti is stiffer than Al, as noted above by D8 (Al ~ 70000 MPa vs Ti ~ 100000MPa).


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## cmh (Jan 30, 2004)

vmajor said:


> ...the interweb is strong with this one.
> 
> Read:
> 
> ...


DeeEight is right on the money with everything he says, and even your own links disprove your statements. 7050's elastic modulus is "70-80" GPa, and 3-2.5 Ti is listed as 106.9GPa. Last time I checked, 106.9 is still more than 80, so titanium is stiffer than aluminum. Just to throw steel in there while we're quoting numbers:

https://www.efunda.com/materials/al...=AISI_4130&show_prop=all&Page_Title=AISI 4130

Elastic modulus 190-210.

So, aluminum _is_ lighter, but most certainly is _NOT_ stiffer than titanium.


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## Zigo (Oct 30, 2008)

According those charts Tensile Strength of AA 7050 is 515MPa and 689MPa for Ti-3Al-2.5V. That is only about 25% diference but the weight of Ti is 42% higher. So if you make the axle of the same weight of Al and Ti than the Al axle will be stronger(in tension) and also stiffer.


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## DeeEight (Jan 13, 2004)

Had a nice long reply, closed the wrong tab....

Zigo : Two points... First as I already said, nobody designs anything structural to maximize its strength or stiffness in material X compared to material Y. Its always done to reduce its weight for the same strength, or to have a compromise (a bit stronger for a bit lighter). Using more of a material than is actually needed to do a job adds to its cost, and manufacturers/builders of things tend not to want to increase costs. 

Second, VMajor cited a titanium alloy not actually used in bicycles outside of frame, seatpost and handlebar tubes. For parts like pedal/BB axles... its 99.9% of the time going to be Ti 6Al-4V which is far stronger than Ti 3Al-2.5V. That particular alloy is about 92% stronger in tension than the 7050 Aluminium. Al frames are only as stiff as they are because the modulus of elasticity cranks up exponentially when you change the section size of the part to something bigger. Increase a tube in diameter from 1 to 2 inches for example, and it becomes eight times stiffer. 

VMajor (does the VM stand for Verified Moron?) : Its a good thing you lacked the time to explain what the T6 (the T is for temper btw) stands for and how it affects the stiffness (it doesn't at all) because I and others would have laughed. Altering the temper of a material changes to its hardness (as in surface hardness) and strength and ductility (how much it stretches before failure). This is usually done in the case of Al alloys by heat-treating. A part is put in an oven and baked at a specific temperature for a specific time. It can also include artificial aging (again involving an oven, but usually a lower temperature and a longer time period spent at it than the initial heat-treating, and it can also involve being quenched rapidly in a fluid like oil). Just because you make a part harder and less ductile (meaning its more brittle), doesn't mean you've done anything to how stiff it is. 

For example, 7005 is the MOST commonly used Al alloy for bicycle frame tubing. In its annealed T0 temper its ultimate tensile strength (UTS for short, how much load it takes to make it fail in tension) is 195MPa, its modulus of elasticity (stiffness basically) is 72.0GPa, its Brinell hardness (how much pressure the surface can resist) is 53 and its elongation at break is 20%. In a T53 temper the numbers become 390MPa, 72.0GPa, 105 and 15% respectively. In the T6 state common to bike frames, its 350MPa, 72.0GPa, 94 and 13%. 

Please notice how in all three tempers, the elasticity remained the same. Exactly the same. Also the density remained constant too, at 2.78g/cc.


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## Zigo (Oct 30, 2008)

I agree with almost everything you wrote but the tensile strenght or even tensile elasticitiy(also shear strenght) doesnt depend on diameter of the tube or its shape. Larger diameter of tubes increase torsion and bending. So all depends on how is the axle stressed.


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## crazy8 (Apr 21, 2009)

*Aerozine with 2X ti rings by Mattias*

I saw this AZ set in a different thread here in WW it has the ti axle and ti rings by Mattias. Looks good and light. It adds up to under 600g total. post 10 and 11 for pix. Am I on the right thread here. Are we talking about Aerozine cranks?

http://forums.mtbr.com/showpost.php?p=5969579&postcount=10


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