ZapoTeX

Dear Bike Forums Users,

I bought a Lezyne cadence and speed sensor. Regarding speed, no problems (I don't mean that I am very fast - I mean that I successfully installed the magnet at the right distance from the sensor).

Regarding cadence, though, the magnet does not fit. I mean, the gap between the crank arm and the chainstay is so small that the magnet does not fit.

My question is: does anybody know the specs of that magnet? I can buy a smaller magnet with similar specs and glue it to the crank arm...

Or, if anybody had a similar problem, any ideas how to solve it?

Huge thanks in advance!

CliffordK

There is no need for the magnet/sensor to be at the end of the crank. It can go somewhere in the middle.

If you want to epoxy it in place, then you can pick up a small Neodymium disc magnet off of E-Bay for cheap.

ZapoTeX

Thanks Clifford!

The problem is, I don't have a ton of room if I want the sensor to overlap with the rear wheel to measure speed as well.

I guess I'll buy a cheap magnet then and McGiver it to the crank arm. Will ANY magnet work? Does it even matter if I flip North and South pole?

I guess I will give it a try :-)

Thanks again!

Tusk

I had the same problem. A small (1/2" diameter) rare earth magnet stuck to the pedal shaft did the trick.

Shimagnolo

^This.
I switched all my bikes to using Neodymium magnets stuck to the pedal spindle years ago.
Of course the pedal spindle needs to be steel, (and not titanium).
And if the gap happens to be too large, you can just stack 2 or 3 to close the distance.

metalheart44

This is what I did too, works like a charm.

ChinookTx

If it is not steel, a small dab of silicon will keep it in place, while making it easy to remove if required.

metalheart44

That will work, I attached mine using double sided tape and that has held without problems.

noglider 

Yes, any magnet is likely to work.

JohnJ80

And for just this reason - the alignment of magnets with pickups - I got rid of all my magnet based sensors a couple of years ago. The dual sensors that provide one pickup for both the wheel and the cranks are the absolute worst too. I don't know how Lezyne computers work with sensors, but if you can can go to the sensors without the external magnets, then do it. The aggravation you leave behind is worth the hit to the pocketbook.

j.