Replacing crank magnet for cadence sensor

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Replacing crank magnet for cadence sensor

Postby AnthonyI » Wed Dec 19, 2012 9:23 pm

I've finally had enough of looking at the ugly zip tied magnet that is attached to the crank arm that records your cadence.

I've read that a rare earth type magnet can be used instead, by placing it inside the pedal spindle.

Questions;
1. Anyone know what size magnets I should get? (I'm using stainless steel speed play zeros)
2. Where is the best place to buy them? (eBay only seems to sell them in lots of 100)

Thanks
Last edited by AnthonyI on Thu Dec 20, 2012 3:52 am, edited 1 time in total.
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by BNA » Wed Dec 19, 2012 9:56 pm

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Re: Replacing crank magnet for speed sensor

Postby Mulger bill » Wed Dec 19, 2012 9:56 pm

I won't have my left crank any other way :)

HERE you go.
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Re: Replacing crank magnet for speed sensor

Postby AnthonyI » Thu Dec 20, 2012 3:59 am

Mulger bill wrote:I won't have my left crank any other way :)

HERE you go.


Many thanks Mulger bill.

Should you glue it in place, or is the magnetic force of the magnet enough to keep it in place?
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Re: Replacing crank magnet for cadence sensor

Postby find_bruce » Thu Dec 20, 2012 8:16 am

AnthonyI wrote:Many thanks Mulger bill.

Should you glue it in place, or is the magnetic force of the magnet enough to keep it in place?

Depends- having picked up this trick from MB the magnet sticks to the spindle with more than enough force.

Stainless steel however is often non-magnetic so you may need to stick it on
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Re: Replacing crank magnet for cadence sensor

Postby visrealm » Thu Dec 20, 2012 8:16 am

Assuming you have a steel/crMo pedal spindle, just place it nearby and it will stick very well, self-centre too since your crank arms are likely aluminum. I still think these should be supplied as standard kit, they're great.
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Re: Replacing crank magnet for cadence sensor

Postby Crawf » Thu Dec 20, 2012 8:23 am

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Re: Replacing crank magnet for cadence sensor

Postby g-boaf » Thu Dec 20, 2012 2:06 pm

You don't even need to use anything to glue it in place. The magnet will be quite strong enough to stay in place by itself and won't fall off. I've had it like this for a long time. Use the magnets suggested by Crawf above.

Try it on your bike, you'll know if it works well enough or not, it will stick on itself with enough force that it will be a bit difficult to take it off. Then you know it's fine. This kind of thing should be standard on bikes, it looks so much better than cable ties. I'm quite lucky having a bike with a built in cadence/speed sensor in the frame so I've got nothing cable tied on.
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Re: Replacing crank magnet for cadence sensor

Postby AnthonyI » Thu Dec 20, 2012 3:34 pm

I've ordered some magnets from Crawf's link - a bargain at a few dollars for 5. :)

I'll see if I can apply them directly to the pedal spindle or crank (stainless steel and aluminium, respectively) and if they don't stick, a spot of silicone might do the job.

Now if I could only do something about the the garmin GSC10 unit..
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Re: Replacing crank magnet for cadence sensor

Postby Mulger bill » Thu Dec 20, 2012 9:24 pm

They'll stick fine unless you are running Ti or possibly stainless pedal spindles. Blutac should be enough in that case.

Nice find Crawf, bookmarked for future needs 8)

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