Does changing SRM chainrings require factory calibration?

Discussion in 'Power Training' started by danfoz, Apr 8, 2013.

  1. danfoz

    danfoz Well-Known Member

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    I'm looking at this crank and wondering if I needed to change rings to FSA Campy 11spd would it need to be done by a pro or could I do it?

    The seller in the ad indicated his current chainrings were installed at the factory along w/a calibration.

    [​IMG]

    Thanks for any assistance.
     
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  2. maxroadrash

    maxroadrash New Member

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    I think all you need is a torque wrench. Preferably calibrated.
     
  3. alienator

    alienator Well-Known Member

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    Why even change them? 10spd chainrings will work on Campy 11spd chain. The inside width between the inner plates where the chain engages the chainring is the same on 11spd Campy chains as it is on 10spd Campy chains. Note that I didn't look to closely at the chainrings on the SRM to see how worn they are.
     
  4. daveryanwyoming

    daveryanwyoming Well-Known Member

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    As mentioned above you probably don't need to change the rings. And if you do you just need to torque them properly, SRMs typically do not change calibration when you change rings, the spiders are pretty solid and aren't very dependent upon the chainrings for stiffness which can affect the torque readings on some other crank based PMs.

    All that said, all it takes is an accurate weight plate in the 30 to 60 pound range and about ten minutes to perform the SRM calibration procedure. It's very easy to do at home. Just go buy a 20kg Olympic style weight plate (the larger center hole in the olympic plates slides right over smaller pedal designs making the test really quick) and have it accurately weighed at a UPS shipping center or other place with a routinely calibrated scale. That's the only special equipment needed.

    SRMs support field calibration and even if chainring changes don't typically change the slope of the PM it's not hard to do a slope calibration at home and worth the effort to get the weight plate and learn how to perform the procedure.

    -Dave
     
  5. danfoz

    danfoz Well-Known Member

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    Thanks, very helpful info. Judging from other photos I think the rings got some good life in them and nice to know they are compatible with 11spd chain if need be.
     
  6. danfoz

    danfoz Well-Known Member

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    The previous owner used a Shimano DA10 setup.

    In that regard are there any compatibility issues with using a Campy11 chain?
     
  7. mx416

    mx416 New Member

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    It shouldn't change the calibration, I've swapped between Specialized, FSA, Sram rings on my SRM with no affect on the slope.

    I would however check the slope just to make sure it's accurate
     
  8. alienator

    alienator Well-Known Member

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    None at all.
     
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