Where to fit cadence sensor on chain stay?

[Mrbez]

Hi Guys,

Sorry if this is a ridiculously daft question, but when I install the cadence sensor on my chain stay, how do I know where to put it?

I know the sensor arm indication line must line up with the spoke magnet, but how far along the chain stay do I need to put it?

Many thanks.

 

[endoman]

the magnet goes on the crank, or in my case directly where the pedal attaches. The sensor goes opposite that.

 

[Mrbez]

Thanks Endo,

So if I put the pedal magnet right at the end of the crank arm and just next to the pedal, place the sensor on the chain stay in line with this?

Thanks.

 

[endoman]

yep, sounds right, anywhere on the crank and directly opposite, all it does is count revolutions. Make sure there is not a huge gap between, like about 2-3mm is perfect.

 

[chillyuk]

Mrbez, are you getting mixed up between the bike computer and the cadence system. The cadence uses a magnet on the crank, which as Endoman says has to line up with the sensor on the chainstay, so it counts the revolutions of your crank. The spoke magnet is for the cycle computer. The magnet goes onto the wheel spoke and the pick up sensor onto your front fork. Just in case you wonder, it makes no difference where on the spoke the magnet goes as it only counts revolutions of the wheel. (or to be pedantic, the sensor counts, not the magnet!)

Oops, Endoman and Mrbez had had a conversation by the time I wrote the above!

 

[Mrbez]

Thanks Chilly.

I think I was overcomplicating it.

 

[Svendo]

Mrbez, are you getting mixed up between the bike computer and the cadence system. The cadence uses a magnet on the crank, which as Endoman says has to line up with the sensor on the chainstay, so it counts the revolutions of your crank. The spoke magnet is for the cycle computer. The magnet goes onto the wheel spoke and the pick up sensor onto your front fork. Just in case you wonder, it makes no difference where on the spoke the magnet goes as it only counts revolutions of the wheel. (or to be pedantic, the sensor counts, not the magnet!)

Unless it is a combined cadence and speed sensor like Garmin's, in which case the spoke magnet goes on a rear wheel spoke so it lines up with the speed sensor line on the combined speed and cadence sensor.

 

[chillyuk]

Unless it is a combined cadence and speed sensor like Garmin's, in which case the spoke magnet goes on a rear wheel spoke so it lines up with the speed sensor line on the combined speed and cadence sensor.

Oh yes, I was forgetting that !

 

[ufkacbln]

Most crank magnets detach after a few miles !

My solutin was to buy a round magnet form a local shop and superglue to the end of the pedal axle.

Neat, and more durable

 

[ufkacbln]

Unless it is a combined cadence and speed sensor like Garmin's, in which case the spoke magnet goes on a rear wheel spoke so it lines up with the speed sensor line on the combined speed and cadence sensor.

The GArmin does not actually "need" the sensor for the spoke magnet.

On my recumbents I have simply folded it back against the boom and only use the cadence sensor.

Everything works fine

 

[02GF74]

glue and cable tie the magnet to the crank arm; sensor on chain stay for comnputa with true cadence sensor (nb. shimano STI computa will give cadence sensor using speed since it "knows" which gear is being used).

 

[endoman]

I got rare earth magnets off ebay, simply attach to pedal axle, no need for glue etc, they are not shifting!

 

[Norry1]

Most crank magnets detach after a few miles !

My solutin was to buy a round magnet form a local shop and superglue to the end of the pedal axle.

Neat, and more durable

Following a suggestion on a forum a while ago - I replaced the cadence magnet with a rare earth magnet (you can buy them for pence). These are very powerful - and usually stick to the pedal at the end of the thread where it comes through the crank. That way it doesn't show and stays put.

Martin

 

[Norry1]

I got rare earth magnets off ebay, simply attach to pedal axle, no need for glue etc, they are not shifting!

I took too long typing

 

[Svendo]

The GArmin does not actually "need" the sensor for the spoke magnet.

On my recumbents I have simply folded it back against the boom and only use the cadence sensor.

Everything works fine

Absolutely right. Only advantage of a wheel sensor is greater accuracy (assuming the wheel diameter is set correctly).