Pedelec sensor - missing magnets

[Phil the drill]

Hi,

I just discovered that the rather 'lumpy' power delivery on the pedelec system of my 905se is down to magnets having seemingly fallen out of the disc on the pedal crank. Is this a common problem? is it worth keeping a spare disc? - I don't know how much they cost, but since my bike is only 5 months old @ present I'm assuming they are covered under warranty (I haven't contacted ETS yet, where I bought the bike).
One question though: When I replace the disc, it looks like a simple job to put it back on the left crank, rather than the right, and to move the sensor to the left also. Will it work if I do this, or will it 'think' I am backpedalling and fail to energise the system? I'm not sure if the system senses direction of travel by measuring uneven gaps in the placement of magnets?
If it is possible to move the sensor system over to the left side, then I can fit a proper chainguard over the chain on the right - and - bingo oily trouser problem sorted!!
Incidentally if it does sense direction by measuring gaps between magnets, is it possible to obtain mirror image discs?

Cheers, Phil.

[carpetbagger]

when i first got my powabyke there was a squeaking every so often,i traced to the magnets rubbing against the sensor. i adjusted the disc and everything has been ok since then but i do periodically inspect it

[Blew it]

Phil,

There should be 5 magnets in the disc, Sorry, I don't know the answer to your other question.

Bob

[Andrew harvey]

I've tried that one before, to lazy to do it properly.
You'll keep knocking the sensor and eventually have to bite the bullet and swap it over. It is no hassle to fit it onto the chain side, unless you have fancy chain guards, or a lack of clearance.
They are normally polarised, try pedalling backwards.

If for some reason you can not fit it to the chain wheel try swapping the magnets, use a good glue.

[Phil the drill]

Originally Posted by Andrew harvey

It is no hassle to fit it onto the chain side, unless you have fancy chain guards, or a lack of clearance. They are normally polarised, try pedalling backwards.

If for some reason you can not fit it to the chain wheel try swapping the magnets, use a good glue.

Hi, it is already on the chain side on the 905se, I'm wanting to move it to the other side, so I can fit a fancy chain guard!
Pedalling backwards - on a pedelec and freewheel hub !! I don't think so. I reckon I'd be giving less than minimal assistance to the motor that way!
Cheers, Phil

[flecc]

You can put it on the left as long as you can reverse the disc so that the same magnet pole is facing the sensor. The direction of rotation doesn't matter.
.

[Phil the drill]

Originally Posted by flecc

You can put it on the left as long as you can reverse the disc so that the same magnet pole is facing the sensor. The direction of rotation doesn't matter.
.

Many thanks, Flecc.
Now I should be able to avoid that 'well oiled trouser' feeling and get some peace at home to boot.....
Cheers, Phil

[ElephantsGerald]

Originally Posted by Phil the drill

Now I should be able to avoid that 'well oiled trouser' feeling and get some peace at home to boot.....

Hi Phil,

I'd be interested to know what chain guard you end up fitting. I'm slowly running out of trousers that aren't covered in oil

Regards,

Elephants

[Phil the drill]

Originally Posted by ElephantsGerald

Hi Phil,

I'd be interested to know what chain guard you end up fitting. I'm slowly running out of trousers that aren't covered in oil

Regards,

Elephants

Hi Elephants,

What started as a rather modest dream (just keep the trouser bottoms oil free) is turning out to be something of a nightmare. I spotted what looked to me to be an ideal chainguard in my local bike shop - it attaches to the bottom bracket, held in place by the outer ring of the bracket, surrounds the chainring and extends a fair way back over the upper part of the chain. So far so good. To fit it would require moving the pedelec sensor ring to the left (seems pretty straightforward) and putting the disc with the magnets on the left crank. Now for the hard part.......the owner of the local bike shop only has one in size 46-50t. The original Wisper is 52t (mine has been modified to 42t), hence it won't fit. He is reluctant to tell me who makes it, insists that it is a 'professional' job to fit and says if I bring my bike in he will see if it can be made to fit and if so order me one in the correct size prior to fitting it.
I, on the other hand, am completely prepared to take the risk of fitting it myself and am too mean to pay him (quite a lot) to do a job which I am perfectly capable of doing myself. He won't order me one unless I let him fit it, nor will he tell me who makes them or where I can get them from....Oh dear, we have an impasse..........
In a nutshell, until one of us cracks (sorry about that!) I'm going nowhere with this.
If anyone out there knows of the whereabouts of this type of chainguard, I'd be delighted to know and will post pictures of finished results when available!

Cheers, Phil

[the_killjoy]

Did the 42 fit without trouble ~ is it standard chainwheel, I could do with a bit more speed on the flat.