# need advise - lightweight mtb crankset 2x9



## ohadamirov (Jun 26, 2008)

Hi guys,I'm new weight weenie here.
In the past,I tried Extralite E-bones with 2x9 setup,but they was too flexy under load, I didn't liked the feeling,so I switched back to M960.
I'm looking for some lightweight and in the same time stiff (enough) 2x9 crankset,my body weight - 79 kg.

What do you think about:
FSA K-FORCE LIGHT - looks good,but have a tank rings.
THM CLAVICULA DP - f***** expensive...
POWERARMS SL - too f+++++ expensive
FRM? 
or some other light cranks... ?!

My bike:
Santa Cruz Blur XC
9350 grams\20.61 lbs - with XTR m960 cranks and Avid 2G 160 rear rotor (front is ASHIMA,but I'm waiting for SCRUBS) 
pic's included!

Thanks in advance,
Ohad.


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## SKullman (Oct 4, 2004)

I've enjoyed my FRM 2 piece cranks for the past 2 seasons. 94mm 2x9, a bit lighter than you.


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## amillmtb (Jun 24, 2005)

Wecome to MTBR Frorums!

I would suggest Tune, but those are pretty pricey too.

The FSA's and the RaceFace Next SL's are both pretty light, you could make them lighter with Extralite Chainrings, or some custom made my Matthias (guy here who makes really light chainrings and cassettes). Another way to drop weight off of those two cranks is a light BB like XTR-m970, which is about 90g with the plastic shield, and wont break the bank. There is a thread here on the new RF Next Carbon SL's..I cant find it...I'm sure someone has the link.

My M-970 BB with 3 spacers and plasic insert:








Without insert:


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## Cheers! (Jun 26, 2006)

Nice bike.

http://forums.mtbr.com/showthread.php?t=477043


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## protocol_droid (Jul 7, 2004)

Nice, I ran the extralite 3X9 on my blur xc. Had it at your weight too!

You could also just swap with extralite chainrings and get it to just about 700 g.
Boy those clavs would be nice, but yeah lot's of coin.


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## conrad (Jan 27, 2004)

*middleburn 2 by 9*

I hear middleburn are going a 27/40 isis drive. 
Curently I run FR turbine 180mm 30/42 Mattias is making me some 27s in ti. 
Way cheaper than new cranks.
How about getting him to make you a 27 granny to fit the 960's? 
Why do I use the 2 by 9...better chain life....really I'm not even close to a WC star in fitness, it just makes more sense to me & with my type of riding it works. Sure it lighter I'm 85kg & how light can you build a bike to last???????? Really?
Conrad


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## ohadamirov (Jun 26, 2008)

*Thank you guys for quick replys*

I have an idea! maybe Matthias will make lighter rings for FSA k-force light? With non-standard BSA ... And it wiil be stiff more than other light cranks? 
What do you think?


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## nino (Jan 13, 2004)

*K-Force light*



ohadamirov said:


> I have an idea! maybe Matthias will make lighter rings for FSA k-force light? With non-standard BSA ... And it wiil be stiff more than other light cranks?
> What do you think?


the K-Force is a nice crankset BUT is useless with its custom bolt diameter and heavy chainrings.

If you are willing to spend this amount of money for a crankset where you have to get different rings and a lighter BB go for it.mProblem is it is the big ring that is overweight but the big rings needs shifting ramps which is something Mattias is not able to do. So i think this is not really an option. Trek offers these same cranks for their top-of-the-line hardtails with 42/29 this year. maybe the 42 is a bit lighter but i really doubt it.

I had them in my hands and was able to get all individual weights...see pics below! Too bad they ruined such a sweet crank with their stupid custom bolt-circle. Sometimes the product managers simply have no clue!!

bye
nino


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## Tiffster (Jan 30, 2008)

What about the normal FSA K Force light crank the 3x9 one - take off the granny ring and bolts and get some custom rings or some TA light weight ones etc.


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## nino (Jan 13, 2004)

Tiffster said:


> What about the normal FSA K Force light crank the 3x9 one - take off the granny ring and bolts and get some custom rings or some TA light weight ones etc.


NO!
With integrated cranks you don't have the option to get the chainline right! By taking off one ring you would have to get the other two rings closer or farther out depending on which ring you take off. But with integrated cranks you can't change chainline!

I just found out that all Shimano cranks are waaay off of a perfect chainline anyway. The rings are 2mm too far out (50mm instead of the usual 48). If you now take out the granny ring you will ride the chain much too much in a crossed position which makes for added friction, loss of power and added wear---->no good!

Only integrated cranks which are designed 2x9 offer a correct chainline such as the above shown FSA, FRM, Rotor...all of them come with some sort of customized rings and aren't really light and they are also quite expensive.

I still believe regular cranksets with separate BBs offer a better variety of chainring sizes and are more versatile when it comes to adjusting chainline. And most important they can easily be lighter than all those integrated cranks.

Just as an example here's my way of a 2x9 cranks (27/42). That's with some older Race Face Next LPs and a 108mm ISIS BB and the 2 rings mounted "inside" leaving alone the outer ring position....the complete crankset comes in under 650g.


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## Tiffster (Jan 30, 2008)

True - but i just swapped my BB Spacer to the non driveside. This moved the chain rings 2.5mm closer to the frame.


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## nino (Jan 13, 2004)

Tiffster said:


> True - but i just swapped my BB Spacer to the non driveside. This moved the chain rings 2.5mm closer to the frame.


ok-that's if you have a slim 68 BB shell or no E-Type...but 2,5mm is not enough. Still better but not enough.


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## Batas (Jan 16, 2004)

What about the crankset center position? Doesn't affect pedal stroke? Having the crank more on the left side... Doesn't look good to me...


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## nino (Jan 13, 2004)

Batas said:


> What about the crankset center position? Doesn't affect pedal stroke? Having the crank more on the left side... Doesn't look good to me...


correct - ideal is in the center which is what i have with my setup. but i doubt you can feel the difference of 2mm. I would run all those Shimano cranks to the left since the chain is so crossed because of the "wrong" chainline that a correction to the left will regain you some power that otherwise gets lost in friction.


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## ohadamirov (Jun 26, 2008)

nino said:


> NO!
> With integrated cranks you don't have the option to get the chainline right! By taking off one ring you would have to get the other two rings closer or farther out depending on which ring you take off. But with integrated cranks you can't change chainline!
> 
> I just found out that all Shimano cranks are waaay off of a perfect chainline anyway. The rings are 2mm too far out (50mm instead of the usual 48). If you now take out the granny ring you will ride the chain much too much in a crossed position which makes for added friction, loss of power and added wear---->no good!
> ...


Hi Nino !
I prefer integrated BB.... How about M970 + light chainrings? like Frm,Extralite,maybe for a bling bling some Carbon - Ti's?
Do you have an experience with Clavicula's? are they stiff compare to E-bones? 
I become to a weight weenie freak  I'm not a millionaire,but I like my bike more lighter... (it was 9.180 grams,with E-bones)

Thank you,
Ohad.


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## Mattias_Hellöre (Oct 2, 2005)

Hi, it´s correct I can´t make chainrings with shifting ramps currently.

I can drill some holes and thread M4 and then screw in cutted down screws, but it doesn´t look good so I don´t do it.

I want to buy a new CNC mill but have to wait some months..


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## Hardtailforever (Feb 11, 2004)

100g for the outer ring on that FSA K-Force (along with the lack of alternatives) is the only real downfall of that crank. Even with that pig, it's still a light crank if you swap the BB for something lighter (or even just lose the centre sleeve). I wonder what some dremmeling could do for it without sacrificing shift performance...

Also, Nino, did you modify your DA front mech for top pull? If so, how did you go about it? I'll be running 2x9 this year and would be interested to know how you did that and how it works.


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## Tiffster (Jan 30, 2008)

just use a speen adapter to convert to top pull.

Or make your own.


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## nino (Jan 13, 2004)

Hardtailforever said:


> 100g for the outer ring on that FSA K-Force (along with the lack of alternatives) is the only real downfall of that crank. Even with that pig, it's still a light crank if you swap the BB for something lighter (or even just lose the centre sleeve). I wonder what some dremmeling could do for it without sacrificing shift performance...
> 
> Also, Nino, did you modify your DA front mech for top pull? If so, how did you go about it? I'll be running 2x9 this year and would be interested to know how you did that and how it works.


as Tiffster already said:
you can get a Top-Pull adapter from Speen.de
the adapter weighs 7,1g and converts your down-pull derailleur into top-pull.

My converted DA 7900 with 34,9 clamp also has a slightly modified clamp to make it fit the oversize 38mm Seattube of my Scott Scale: 83g

The XTR 970 it replaces was almost 150g!!


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## Megaclocker (Sep 28, 2005)

+ 1 on the Next LP,

Mine came under 650gr too.

Race Face NexT Lp CrankArms (Mine are pigs at 425gr)
29T Specialities TA
42T Sugino (tuned)
Aluminium Hardware
Eriksen Ti BB 107 x 73mm (Very nice BB)


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## Cheers! (Jun 26, 2006)

nino said:


> as Tiffster already said:
> you can get a Top-Pull adapter from Speen.de
> the adapter weighs 7,1g and converts your down-pull derailleur into top-pull.
> 
> ...


is that really a DA 7900? It looks like a 7800 front derailleur to me.

here is what a 7900 looks like


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## Cheers! (Jun 26, 2006)

Megaclocker said:


> Eriksen Ti BB 107 x 73mm (Very nice BB)


Nice! I didn't know Kent Eriksen made bottom brackets. Where did you buy it from? Kent's website does not list any bottomr brackets.


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## nino (Jan 13, 2004)

Cheers! said:


> is that really a DA 7900? It looks like a 7800 front derailleur to me.
> 
> here is what a 7900 looks like
> 
> [/IMG]


yes sure - i meant 7800. sorry!

I am using the 7900 rear derailleur and it also works great on a 11-32 cassette. It is 16g lighter than the 7800 in standard trim. I am about to get mine under the 140g mark.


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## Cheers! (Jun 26, 2006)

Is the pull ratio of the 7900 front derailleur and rear derallieur the same as the 7800 series?


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## nino (Jan 13, 2004)

Cheers! said:


> Is the pull ratio of the 7900 front derailleur and rear derallieur the same as the 7800 series?


the rear is definitely unchanged and as far as i know the front as well.


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## ScaryJerry (Jan 12, 2004)

Front derailleur pull ratio has been changed for 7900 unfortunately.


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## nino (Jan 13, 2004)

ScaryJerry said:


> Front derailleur pull ratio has been changed for 7900 unfortunately.


well -then get the 7800...it works.


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## Megaclocker (Sep 28, 2005)

Cheers! said:


> Nice! I didn't know Kent Eriksen made bottom brackets. Where did you buy it from? Kent's website does not list any bottomr brackets.


Bought it on ebay a couple of days ago. Costed me quite a lot (115usd). Retail on the box was 199$.Came in at 141gr. (68/73 x 107mm)

I don't think they are made anymore. They run on two 6903bearing (they are easy too change too). The bb axle is oversized in the center and very different from regular square taper axle. It's like 2.5cm of diameter in the middle. They also have an ajustable chainline (cups with lockring on each side). That bb will hopefully last a lifetime. I will try to post a pics once my crankset is polished.


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## qasko (Feb 2, 2009)

Hello can I use XTR shifters + speen + FD 7900 front derailleur ? 
Work it good ?


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## nino (Jan 13, 2004)

qasko said:


> Hello can I use XTR shifters + speen + FD 7900 front derailleur ?
> Work it good ?


yes-works perfect!

Just make sure you get the new,actual MTB-version of the Speen adapter which is longer than the one i show ed above! The longer one works smoother with less handforce.


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## qasko (Feb 2, 2009)

I bought speen* this week , its good ? I dont know :madman:


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## nino (Jan 13, 2004)

qasko said:


> I bought speen* this week , its good ? I dont know :madman:


The correct one is called "Umlenker Shimano for MTB"

the old-version now is sold for cyclocross only.


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## qasko (Feb 2, 2009)

Thanks nino ! :thumbsup:


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## 2times (Jul 14, 2006)

Nino, I thought you were using a road cassette on that bike? Can you post a pic of your handlebar set up? 

Thanks in advance!


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## nino (Jan 13, 2004)

2times said:


> Nino, I thought you were using a road cassette on that bike? Can you post a pic of your handlebar set up?
> 
> Thanks in advance!


Naah - that's on my MTB!


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## 2times (Jul 14, 2006)

Thanks Nino!:thumbsup: 

Great Pics as always!


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## nino (Jan 13, 2004)

2times said:


> Thanks Nino!:thumbsup:
> 
> Great Pics as always!


I forgot to give you the info about the cassette used:
i use MTB cassettes on both my Scales

It used to be a 11-32 10s Titanium cassette on my V-Brake Scale and a 11-32 9s titanium cassette on my other Scale, my Winterbike. Right now one i am re-building both my bikes quite a bit. I am converting my V-Brake bike into discs and also tore down my winterbike completely....this time of the year is wrenching time anyway - I use tuned Dura Ace 7900 derailleurs on both bikes. All that's needed is a 10t upper pulley to make the short caged DA derailleurs fit under the 32 cassettes.

Shown below the actual status of my former V-Brake Scale: 7,4 Kilos as pictured. Soon to be mounted: Tune Saddle and Formula R1 which might get it to weigh about 7,2 Kilos. That's still with the huge Conti RK 2,2" tires installed. No fancy Schmolke,AX-Lightness parts and no extreme wheels either. That Scale LTD frame is going into it's 6th year (weighed 1002g with v-brake studs...now under 1000g)....

The box with left-over parts from the other bike is well worth a couple $$$


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## COLINx86 (Apr 8, 2009)

If you want you can send me that box.


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