How to fit Garmin cadence sensor magnet on madfiber spokes

Andrewbmc
Andrewbmc Posts: 5
edited December 2013 in Workshop
Hey guys

I just purchased a Garmin GSC 10 cadence sensor, and I realizes the spoke magnet and its plastic housing piece wouldn't fit on my Madfiber wheel spoke, since the spokes themselves are not the traditional rod shape, they are flat and wide and made out of carbon!

Anyone has any suggestion or knew some kind of adaptor which I can use with the magnet rather than the plastic housing they supplied?

Thanks

Andrew

Comments

  • BillyMansell
    BillyMansell Posts: 817
    You could glue a neodymium or rare earth magnet to one of the spokes. Alternatively use the in-built gps for speed and the GSC 10 for cadence only.
  • Andrewbmc
    Andrewbmc Posts: 5
    BillyMansell wrote:
    You could glue a neodymium or rare earth magnet to one of the spokes. Alternatively use the in-built gps for speed and the GSC 10 for cadence only.


    Hi billy,

    thank you so much for the suggestion. So you meant if I use GSC 10 for cadence only, then I don't need to install the sensor magnet at all? There are another pedal magnet too, do I need to install that one too?
  • angry_bird
    angry_bird Posts: 3,786
    If you just want to use it for cadence then yes, you just install the one magnet on the crank arm and don't need to install one on the wheel.
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  • BillyMansell
    BillyMansell Posts: 817
    Andrewbmc wrote:
    BillyMansell wrote:
    You could glue a neodymium or rare earth magnet to one of the spokes. Alternatively use the in-built gps for speed and the GSC 10 for cadence only.


    Hi billy,

    thank you so much for the suggestion. So you meant if I use GSC 10 for cadence only, then I don't need to install the sensor magnet at all? There are another pedal magnet too, do I need to install that one too?
    That's correct, the spoke magnet is optional and only necessary if you're not using the in-built gps for speed. The other magnet you will need to install to the right crank arm so that the GSC 10 can measure your cadence.
  • Andrewbmc
    Andrewbmc Posts: 5
    Got it. Nice and clear. Thank you guys for the help.
  • MikeRaw
    MikeRaw Posts: 1
    Those solutions are good until you find yourself snowed in and on the turbo trainer, you wont have any speed/distance data... maybe this solution of sticking the magnet on with either double-sided tape or a weak glue is better suited?

    http://www.ebay.co.uk/itm/Blade-Spoke-S ... 43c34a8fc2
  • Andrewbmc
    Andrewbmc Posts: 5
    BillyMansell wrote:
    Andrewbmc wrote:
    BillyMansell wrote:
    You could glue a neodymium or rare earth magnet to one of the spokes. Alternatively use the in-built gps for speed and the GSC 10 for cadence only.


    Hi billy,

    thank you so much for the suggestion. So you meant if I use GSC 10 for cadence only, then I don't need to install the sensor magnet at all? There are another pedal magnet too, do I need to install that one too?
    That's correct, the spoke magnet is optional and only necessary if you're not using the in-built gps for speed. The other magnet you will need to install to the right crank arm so that the GSC 10 can measure your cadence.

    Sorry billy,

    you meant the pedal magnet on the left crank arm correct? Not the right crank arm. Because the GSC unit is suppose to be install on the left chain-stay and the pedal magnet needs to be within 5mm from the GSC unit.
  • keef66
    keef66 Posts: 13,123
    Beneath the left chainstay sounds like the most sensible place. Out of the way of the drivetrain, and underneath means even if it's knocked into the wheel it's unlikely to jam / cause damage. So rare earth magnet on the crank end of the LH pedal axle.
  • sungod
    sungod Posts: 17,182
    ^^^this is the best way

    to attach a small rare earth magnet to a cf spoke, electrical tape works very well
    my bike - faster than god's and twice as shiny
  • BillyMansell
    BillyMansell Posts: 817
    Andrewbmc wrote:
    BillyMansell wrote:
    Andrewbmc wrote:
    BillyMansell wrote:
    You could glue a neodymium or rare earth magnet to one of the spokes. Alternatively use the in-built gps for speed and the GSC 10 for cadence only.


    Hi billy,

    thank you so much for the suggestion. So you meant if I use GSC 10 for cadence only, then I don't need to install the sensor magnet at all? There are another pedal magnet too, do I need to install that one too?
    That's correct, the spoke magnet is optional and only necessary if you're not using the in-built gps for speed. The other magnet you will need to install to the right crank arm so that the GSC 10 can measure your cadence.

    Sorry billy,

    you meant the pedal magnet on the left crank arm correct? Not the right crank arm. Because the GSC unit is suppose to be install on the left chain-stay and the pedal magnet needs to be within 5mm from the GSC unit.
    Doh! After all these years and still don't know my left from my right.

    Regarding the gap between sensor and magnet, when the gap is too small it can produce odd readings (my cadence appeared double what it actually was). Not a problem if it does, you just rotate the sensor on the chain stay a bit more away from the magnet until harmony is restored.
  • crankycrank
    crankycrank Posts: 1,830
    I like this tape for mounting magnets. Very strong, lasts a long time and can be peeled off without leaving much or any residue which can be dissolved easily with WD-40 or other solvents. Note that this isn't the white foam type tape used for hanging pictures and such that leaves a mess when removed. 123139.JPG
  • markhewitt1978
    markhewitt1978 Posts: 7,614
    Are there no more elegant ways to have a cadence sensor rather than taping or cable tying magnets to the crank?
  • sungod
    sungod Posts: 17,182
    glue a rare earth magnet to the crank (use silicone, epoxy or gel superglue), or in some cases you can simply touch the magnet to the inside end of the pedal axle and it'll hold securely
    my bike - faster than god's and twice as shiny
  • on-yer-bike
    on-yer-bike Posts: 2,974
    A Campagnolo Eurus or Shamal magnet may fit one of your spokes. These wheels ship with a magnet designed for wide bladed spokes. Is reading the speed off the wheel more acurate than GPS?
    http://www.evanscycles.com/products/cam ... wwodISwAsA
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  • rolf_f
    rolf_f Posts: 16,015
    sungod wrote:
    glue a rare earth magnet to the crank (use silicone, epoxy or gel superglue), or in some cases you can simply touch the magnet to the inside end of the pedal axle and it'll hold securely

    In most cases the rare earth magnet will hold onto the axle end without glue - only if you are too flash for your own good and use Ti axles will you have to much around with araldite etc!

    And of course the rare earth magnet means you don't need to fuss about the position of the sensor too much.
    Faster than a tent.......
  • buckles
    buckles Posts: 694
    MikeRaw wrote:
    Those solutions are good until you find yourself snowed in and on the turbo trainer, you wont have any speed/distance data...
    If you're on the turbo your speed and distance is always zero and zero...
    on-yer-bike wrote:
    A Campagnolo Eurus or Shamal magnet may fit one of your spokes. These wheels ship with a magnet designed for wide bladed spokes. Is reading the speed off the wheel more acurate than GPS?
    http://www.evanscycles.com/products/cam ... wwodISwAsA
    As long as you measure your wheel circumference correctly, then yes.
    25% off your first MyProtein order: sign up via https://www.myprotein.com/referrals.lis ... EE-R29Y&li or use my referral code LEE-R29Y
  • smoggysteve
    smoggysteve Posts: 2,909
    MikeRaw wrote:
    Those solutions are good until you find yourself snowed in and on the turbo trainer, you wont have any speed/distance data... maybe this solution of sticking the magnet on with either double-sided tape or a weak glue is better suited?

    http://www.ebay.co.uk/itm/Blade-Spoke-S ... 43c34a8fc2

    Are you likely to be using £1500+ carbon wheels on a turbo trainer? or like most a cheap clincher with normal spokes for indoors?

    I have an old shimano rs30 rim for indoor with a speed magnet on it and leave the carbon tubs for the outdoors
  • smoggysteve
    smoggysteve Posts: 2,909
    just in case people dont know how these work. when you use a garmin gps outdoors, it will pick up the cadence sensor on the pedal and the wheel. When it receives a gps signal IT IGNORES the wheel sensor. What it will do is calibrate it for you based on revolutions over distance so it knows what wheel size you run if gps is temporarily lost. once it gets gps back it goes back to ignoring the wheel.

    This is useful for knowing that when you are indoors the garmin knows your wheel automatically even if you swap to a cheap clincher to stick your magnet on. Thetefore once you have calibrated your unit with a cheaper wheel you dont have to mess around sticking magnets on expensive carbon rims. Sure you may lose gps outside once in a while and have no magnet backup if your on your carbon rims but your unit will continue to calculate your speed over a distance covered when coverage returns.

    No need to stick any magnets on carbon rims full stop

    And if you can afford mad fiber rims and a turbo, you can afford a cheap rim and cassette for indoor use.
  • EBUK
    EBUK Posts: 17
    Yup, agree with SmoggySteve - best to have a cheap wheel for the turbo that has a specific turbo tyre fitted to it. Also saves mucking about with swapping tyres whenever you want to go on the turbo.

    If you're using your Garmin on the turbo then when you turn it on just go through the Settings menus and switch the GPS off (unsurprisingly, the option is found under the GPS menu). This then means the Garmin only uses the wheel sensor, therefore giving you cadence and speed, relying on the magnets on the crank / wheel.

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