magnets qq

blablablacksheep
blablablacksheep Posts: 1,377
edited October 2012 in Road buying advice
Quick question, just bought some
http://www.ebay.co.uk/itm/Neodymium-Dis ... 000wt_1139

Planning to stick one of these inside the gap on the other side of the crank where the pedal is, so i dont have to use my Garmins magnet which is ugly and really not very tidy.

will this work? i have done this on a recommendation from reading around, but just wanted to check as i know they quite strong and don't want them to interfere with the electronics/GPS/cadence sensor ect or cause a accident ie (somehow get me wrecked) :D
London2Brighton Challange 100k!
http://www.justgiving.com/broxbourne-runners

Comments

  • mfin
    mfin Posts: 6,729
    Will work fine. Done it on 5 bikes now
  • Pumpkin Positive
    Pumpkin Positive Posts: 392
    Yes they'll work OK. When I first went down this route I bought a magnet which was too large and I noticed that I got erroneous speed readings from my speed / cadence sensor. There are two 'receivers' which measure speed and cadence in the sensor which attaches to your chainstay. I think (although someone more knowledge than I may come along and rubbish what I'm about to say) that in my case the magnet on my pedal crank was too powerful and was influencing the 'speed receiver'. The speed receiver was getting an input from the wheel magnet AND the cadence magnet.
  • Velonutter
    Velonutter Posts: 2,437
    How do you securely fasten these to your cranks with out damaging the lacquer?
  • apreading
    apreading Posts: 4,535
    I think you stick them on the end of the pedal spindle - so they dont touch the cranks.

    Just bought some myself.
  • Velonutter
    Velonutter Posts: 2,437
    apreading wrote:
    I think you stick them on the end of the pedal spindle - so they dont touch the cranks.

    Just bought some myself.

    Cheers, just bought some, do you stick them on with Araldite then?
  • apreading
    apreading Posts: 4,535
    They are supposed to be REALLY powerful magnets - pedal spindle is metal - so no need for glue.

    see http://i.ebayimg.com/t/Stealth-MAGNET-f ... ~60_57.JPG
  • mfin
    mfin Posts: 6,729
    Velonutter wrote:
    apreading wrote:
    I think you stick them on the end of the pedal spindle - so they dont touch the cranks.

    Just bought some myself.

    Cheers, just bought some, do you stick them on with Araldite then?

    No, you'll find they just are easily magnetic enough to just pop on the pedal spindle and hold, no glue. 2 seconds flat.
  • Velonutter
    Velonutter Posts: 2,437
    Brill Thanks MFin
  • Pumpkin Positive
    Pumpkin Positive Posts: 392
    mfin wrote:
    Velonutter wrote:
    apreading wrote:
    I think you stick them on the end of the pedal spindle - so they dont touch the cranks.

    Just bought some myself.

    Cheers, just bought some, do you stick them on with Araldite then?

    No, you'll find they just are easily magnetic enough to just pop on the pedal spindle and hold, no glue. 2 seconds flat.
    I've done about 4k miles with mine on the spindle - no glue. The garmin supplied lasted a few hundred miles. And if they do come off for whatever reason they cost pennies to replace.

    They are really powerful magnets, you need to take care when handling them. If you order them on ebay and they don't arrive its probably because they have stuck themselves to the inside of the postie's van!
  • apreading
    apreading Posts: 4,535
    yep - mine arrived today - wrapped in bubble wrap and in a jiffy bag.

    The jiffy bag is stuck to the radiator behind my desk as I type...!
  • mfin
    mfin Posts: 6,729
    Velonutter wrote:
    Brill Thanks MFin

    Unless you have Ti spindles, then they'll need glue as Ti contains no magnetic witchcraft particles if I remember correctly!
  • redvee
    redvee Posts: 11,922
    Both my bikes have nedidiium(sp) rare earth cadence magnets. Had to buy a pack of ten so have eight on the side of the cooker.
    I've added a signature to prove it is still possible.
  • hulla the hulla
    hulla the hulla Posts: 338
    Do these bad boys mess with heart rate monitors etc ? Also does anyone know of any reason why they would not work with the cadence unit of a Polar CS200CAD ? My Polar magnet got knocked off and a replacement is £6.49 !!
    A person who aims at nothing is sure to hit it

    Canyon Aeroad 7.0 summer missile
    Trek 2.1 winter hack
  • apreading
    apreading Posts: 4,535
    If your heart rate monitor is anywhere near you pedals they might, but I cant think why you would ride a bike like that...!
  • hulla the hulla
    hulla the hulla Posts: 338
    apreading wrote:
    If your heart rate monitor is anywhere near you pedals they might, but I cant think why you would ride a bike like that...!
    Lol! Good point, well made! Ordered now anyway so ill find out in a few days.
    A person who aims at nothing is sure to hit it

    Canyon Aeroad 7.0 summer missile
    Trek 2.1 winter hack
  • rolf_f
    rolf_f Posts: 16,015
    apreading wrote:
    If your heart rate monitor is anywhere near you pedals they might, but I cant think why you would ride a bike like that...!

    And you'd need to be alternating your HRM being near the pedals and then not near the pedals! :lol:

    TBH, aside from the Ti spindle issue, I don't get why the computer manufacturers don't put these in as standard. They are soooo much better than ordinary magnets. They provide proper mounts for the computer rather than bits of blue tack and gaffer tape so why not do the same for the cadence sensor?
    Faster than a tent.......

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