Dual sensor (speed/cadence) arm position

khisanth
khisanth Posts: 41
edited February 2014 in Road general
I have one of the dual sensors that has a movable arm to pickup the magnet on the spokes for speed. Works great. However I have broken one previously as the arm got knocked by my clumsy foot into the spokes and i rode off breaking it.

So is it better to have the arm pointed downwards so its protected from being knocked by the chainstays? I am going to try it, but wondered what peoples experience was. :)

Comments

  • neilvx
    neilvx Posts: 137
    My Wahoo blue SC can only go on one way and the arm is pointing down.
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  • rolf_f
    rolf_f Posts: 16,015
    khisanth wrote:
    So is it better to have the arm pointed downwards so its protected from being knocked by the chainstays? I am going to try it, but wondered what peoples experience was. :)

    That's the normal way you do it. Some bikes have insufficient clearance and that's really the only circumstance where you'd consider having the arm pointed upwards.
    Faster than a tent.......
  • bsharp77
    bsharp77 Posts: 533
    As Rolf F said, if you have space for it, it would be better to have the arm facing down.

    On my last bike I didn't have the clearance and had to have the arm pointing upwards - looked really vulnerable and couldn't help but think about it ploughing into the spokes if the sensor moved a small bit - but fortunately it never did.
  • R0B75
    R0B75 Posts: 376
    The arm is up on the Garmin sensor on my winter bike because there is no clearance for the magnet when inline with the crank arm sensor. It's never been a problem yet.
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  • dulwichiron
    dulwichiron Posts: 86
    Rolf F wrote:
    khisanth wrote:
    So is it better to have the arm pointed downwards so its protected from being knocked by the chainstays? I am going to try it, but wondered what peoples experience was. :)

    That's the normal way you do it. Some bikes have insufficient clearance and that's really the only circumstance where you'd consider having the arm pointed upwards.

    I had insufficient clearance on mine so rather than have the arm in the "up" position i put the sensor underneath the stay. Not my bikes but check this thread.. viewtopic.php?t=12933107&p=18452019
  • Mikey23
    Mikey23 Posts: 5,306
    No clearance here either so has to stay up. No probs so far
  • khisanth
    khisanth Posts: 41
    Thanks everyone. Kind of a moot point for me as the arm can only point upwards with only a little bit of movement. I just have to be a bit more careful when getting on and off the bike in future !
  • rolf_f
    rolf_f Posts: 16,015
    Worth looking carefully at the clearances to see if you can put the arm in the down position if you move the sensor a little further along the chainstay. Obviously then the cadence magnet won't work - but you can solve that by replacing it with a rare earth magnet which can sit on the end of the pedal bolt. That gives you much more leeway on the sensor position.
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  • ytchi
    ytchi Posts: 61
    You can also put the magnet on a drive side spoke to give more clearance past the arm, this was the only way I could get a garmin sensor to fit on my Ridley Noah
  • maltloaf_df
    maltloaf_df Posts: 118
    Mine is down but the whole unit is tilted slightly out wards to pick up the cadence magnet. I've done 3000 miles like this, never had an issue
  • smoggysteve
    smoggysteve Posts: 2,909
    If your computer is a gps it does a pretty decent job of judging speed on its own so move it so your cadence is in line and forget the wheel magnet as on a gps you dont need it. if you lose cadence then its pointless having the unit there at all.
  • maltloaf_df
    maltloaf_df Posts: 118
    SmoggySteve wrote:
    If your computer is a gps it does a pretty decent job of judging speed on its own so move it so your cadence is in line and forget the wheel magnet as on a gps you dont need it. if you lose cadence then its pointless having the unit there at all.

    I partially agree but I changed wheels recently and forgot to swap the wheel magnet over for a couple of rides. The speed on my garmin was much less consistent, as in there's a lag when you slow for a climb or start a fast descent for example. The speed sensor reacts faster than the gps based speed so smooths all this out and gives a better set of data
  • mfin
    mfin Posts: 6,729
    If you dont have enough clearance for it with the arm down, will it work if you had a really thin magnet? If so, you can get all sorts of thin and flat magnets from eBay. I did this one bike for this reason, using insulation tape to put the magnet on one of the bladed spokes. It's also far tidier than with a screw on magnet. (Same with the cadence magnet, throw that away and get a one that sucks itself onto the back of the pedal spindle, no zip ties at all).
  • gubber12345
    gubber12345 Posts: 493
    maltloaf_df wrote:
    Mine is down but the whole unit is tilted slightly out wards to pick up the cadence magnet. I've done 3000 miles like this, never had an issue
    Me too and absolutely no probs so far......touch wood :P :P :P
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