Dual sensor (speed/cadence) arm position

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khisanth
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Dual sensor (speed/cadence) arm position

Postby khisanth » Thu Feb 13, 2014 11:33 am

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. :)

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Neilvx
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Re: Dual sensor (speed/cadence) arm position

Postby Neilvx » Thu Feb 13, 2014 11:38 am

My Wahoo blue SC can only go on one way and the arm is pointing down.
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Rolf F
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Re: Dual sensor (speed/cadence) arm position

Postby Rolf F » Thu Feb 13, 2014 11:50 am

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.
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bsharp77
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Re: Dual sensor (speed/cadence) arm position

Postby bsharp77 » Thu Feb 13, 2014 12:08 pm

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
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Re: Dual sensor (speed/cadence) arm position

Postby R0B75 » Thu Feb 13, 2014 12:55 pm

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.

DulwichIron
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Re: Dual sensor (speed/cadence) arm position

Postby DulwichIron » Thu Feb 13, 2014 14:18 pm

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

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Mikey23
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Re: Dual sensor (speed/cadence) arm position

Postby Mikey23 » Thu Feb 13, 2014 20:54 pm

No clearance here either so has to stay up. No probs so far

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khisanth
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Re: Dual sensor (speed/cadence) arm position

Postby khisanth » Fri Feb 14, 2014 14:58 pm

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 !

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Rolf F
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Re: Dual sensor (speed/cadence) arm position

Postby Rolf F » Fri Feb 14, 2014 15:15 pm

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
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Re: Dual sensor (speed/cadence) arm position

Postby ytchi » Sat Feb 15, 2014 12:34 pm

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
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Re: Dual sensor (speed/cadence) arm position

Postby maltloaf_df » Sun Feb 16, 2014 00:59 am

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
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Re: Dual sensor (speed/cadence) arm position

Postby SmoggySteve » Sun Feb 16, 2014 07:56 am

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
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Re: Dual sensor (speed/cadence) arm position

Postby maltloaf_df » Sun Feb 16, 2014 10:18 am

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

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mfin
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Re: Dual sensor (speed/cadence) arm position

Postby mfin » Sun Feb 16, 2014 11:13 am

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
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Re: Dual sensor (speed/cadence) arm position

Postby gubber12345 » Sun Feb 16, 2014 17:00 pm

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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