Swapping crank arms on SRM - FSA SLK?

Discuss light weight issues concerning road bikes & parts.
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RudeE
Posts: 82
Joined: Mon Feb 08, 2010 5:36 pm

by RudeE

I'm wondering if anybody knows if I can swap the crank arms on my FSA SLK SRM?
I want to go back to 170's and see the Sram S900 cranksets go cheap on ebay.
(For that matter, also doing Red rings would look better on there as well.)

here is a pic:
Image

by Weenie


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LarsEjaas
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Location: Aarhus, Denmark

by LarsEjaas

RudeE wrote:I'm wondering if anybody knows if I can swap the crank arms on my FSA SLK SRM?
I want to go back to 170's and see the Sram S900 cranksets go cheap on ebay.
(For that matter, also doing Red rings would look better on there as well.)

here is a pic:
Image


You can swap to SLK crank arms with a different length, But you can't switch to other brands of crank arms :sorry:

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ms6073
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Location: Houston, Texas

by ms6073

I did not know SRM offered an FSA SL-K powermeter - the one in that image looks like the FSA Team Issue.

Also, I got the impression from a call to SRM last year that crank arms for the SRM Dura Ace, FSA, and SRAM powermeters were interchangeable but that the Specialized and Cannondale SI were not because they used a different 'spline' for attachment to the powermeter. I think a call/email to an SRM service center would resolve the question.
Michael - The Anaerobic Threshold is neither...

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bcheung
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Location: Herndon, VA

by bcheung

I spoke with SRM on the exact issue last year. Here is what they told me:

Brian,

The K-Force Light cranks cost $770 with the Ceramic BB included or $520 without the BB. We have 170, 172.5 and 175mm in stock.

If you send it here we can change them and will not charge for labor if you purchase the new cranks – or you can order the cranks and do it yourself.

Leslie

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ms6073
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Location: Houston, Texas

by ms6073

The 'spline' that inserts into the powermeter spider is the key and I while I thought it was common between the Dura Ace, FSA, and SRAM power meters, as with all things I may be mistaken. While I do not have an image of the Dura Ace or SRAM power meters from behind, here are images of the FSA Team Issue and FSA K-Force Light (sorry about the image size):
Image
Image
Which is quite a bit different from the Specialized FACT and Cannondale SI:
Image
Michael - The Anaerobic Threshold is neither...

Geoff
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Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Don't forget to re-calibrate when you change the cranks. I was quite suprised to see how much a crank change affected slope, notwithstanding an identical torque setting.

RudeE
Posts: 82
Joined: Mon Feb 08, 2010 5:36 pm

by RudeE

LarsEjaas wrote:
RudeE wrote:I'm wondering if anybody knows if I can swap the crank arms on my FSA SLK SRM?
I want to go back to 170's and see the Sram S900 cranksets go cheap on ebay.
(For that matter, also doing Red rings would look better on there as well.)



You can swap to SLK crank arms with a different length, But you can't switch to other brands of crank arms :sorry:


The FSA cranks I see for sale have the integrated spiders (first thing I looked for)
I thought that all these Carbon cranks were the same - S900, Truvative, Bontrager...FSA? they look very similar.

http://cgi.ebay.com/SRAM-S900-Carbon-GX ... 1c0f356418

http://cgi.ebay.com/SRAM-TRUVATIV-ROULE ... 5637eccfcc

http://cgi.ebay.com/Bontrager-triple-ca ... 27afaad772

RudeE
Posts: 82
Joined: Mon Feb 08, 2010 5:36 pm

by RudeE

bcheung wrote:I spoke with SRM on the exact issue last year. Here is what they told me:

Brian,

The K-Force Light cranks cost $770 with the Ceramic BB included or $520 without the BB. We have 170, 172.5 and 175mm in stock.

If you send it here we can change them and will not charge for labor if you purchase the new cranks – or you can order the cranks and do it yourself.

Leslie


Wow, they are charging way to much for $150 dollar cranks, if these are the same.

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ms6073
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Location: Houston, Texas

by ms6073

RudeE wrote:Wow, they are charging way to much for $150 dollar cranks, if these are the same.


Not even the whole crankset, just the crankarms which I think because of the high cost from SRM is why the OP posted the question. Based on a bit more research via Google, I came across this link of a Quarg Quarq CinQo Saturn install on SRAM cranks. Based on the images of the drive side crank arms, assuming the orginal poster has a wireless SRM, I am pretty certain that the SRAM and FSA crankarms should work interchangeably with the SRM. If the SRM is wired, then this is not as certain because if you reference the images above, the splines on the crankarm/spindle of the wireless crank in the first image are not the same as the splines of the wired SRM in the second image.
Michael - The Anaerobic Threshold is neither...

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LarsEjaas
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Location: Aarhus, Denmark

by LarsEjaas

ms6073 wrote:
RudeE wrote:Wow, they are charging way to much for $150 dollar cranks, if these are the same.


Not even the whole crankset, just the crankarms which I think because of the high cost from SRM is why the OP posted the question. Based on a bit more research via Google, I came across this link of a Quarg Quarq CinQo Saturn install on SRAM cranks. Based on the images of the drive side crank arms, assuming the orginal poster has a wireless SRM, I am pretty certain that the SRAM and FSA crankarms should work interchangeably with the SRM. If the SRM is wired, then this is not as certain because if you reference the images above, the splines on the crankarm/spindle of the wireless crank in the first image are not the same as the splines of the wired SRM in the second image.


Are you sugesting that the Quarg and Wireless SRM crankarms are inter-change-able?

It would be really nice if it is possible to just change the crankarms for a different system (say SRAM to Shimano).

mieke@quarq
in the industry
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Joined: Sat Aug 23, 2008 9:44 pm

by mieke@quarq

LarsEjaas wrote:
ms6073 wrote:
RudeE wrote:Wow, they are charging way to much for $150 dollar cranks, if these are the same.


Not even the whole crankset, just the crankarms which I think because of the high cost from SRM is why the OP posted the question. Based on a bit more research via Google, I came across this link of a Quarg Quarq CinQo Saturn install on SRAM cranks. Based on the images of the drive side crank arms, assuming the orginal poster has a wireless SRM, I am pretty certain that the SRAM and FSA crankarms should work interchangeably with the SRM. If the SRM is wired, then this is not as certain because if you reference the images above, the splines on the crankarm/spindle of the wireless crank in the first image are not the same as the splines of the wired SRM in the second image.


Are you sugesting that the Quarg and Wireless SRM crankarms are inter-change-able?

It would be really nice if it is possible to just change the crankarms for a different system (say SRAM to Shimano).


The SRAM S900 / Bontrager Race X Lite / Truvativ Rouleur Carbon cranks all have the same spider interface. They all have the 3 bolt interface as seen in the first photo above so they are interchangeable with each other. Those three brands are not interchangeable with the FSA Team Issue cranks that the OP has on his bike. The FSA Team Issue and FSA SL-K Light (http://www.quarq.com/) cranks that we use have the 4 bolt spider interface as seen in the second photo.

The 3rd photo looks like the Cannondale Hollowgram spider interface. It is yet again different than the Specialized spider interface.

In other words, as another poster pointed out, you don't have much leeway for switching between crank manufacturers (SRAM, FSA, Cannondale) with your SRM or Quarq powermeters.

You could, however, send your SRM powermeter and crankset to us and have a Quarq power sensor mounted on the cranks as long as they are a model we support too (FSA, SRAM, Specialized, Cannondale). :-)

Mieke Meyer
Quarq Technology

Stefano
Posts: 244
Joined: Sun Dec 19, 2010 4:24 am
Location: Ann Arbor, Michigan

by Stefano

Hi!

Sorry to dredge up an old topic- but I recently bought a 7800 wired SRM with the four-bolt mounting. I like the cranks that are on there just fine, but I think in the future I may end up changing crank length. I was hoping that I could use a carbon crank at that point. Does anyone know if the new Campagnolo cranks or the FSA carbon cranks are interchangeable with the dura ace spider?

Thanks!

Stefano

Geoff
Posts: 5136
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Yeah, no. The old, proprietary-crank Professional SRM only accepts the proprietary cranks. If you want to change cranks (or crank lengths), you can only use the SRM crankarms. The SRM cranks are very good (from the perspective of consistency).

by Weenie


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