Disc-mounted magnet - where to buy?

bissona

Active member
Patreon
Oct 14, 2018
137
106
Guernsey
Hi,

One of our little speed sensor magnets (Focus JAM2 / Shimano E8000) has been knocked off and we're struggling to find a replacement. Would anyone know where to get one? Found a place in Italy that only want €3 for the magnet but €17 for postage!

Cheers.
 

bissona

Active member
Patreon
Oct 14, 2018
137
106
Guernsey
While waiting you could use a normal magnet and tape it to your rotor. Have done that on my spare wheels and it works great.

Without wishing to appear too dim..... best best for a small magnet? The only place I can think of is a clasp from one of SWMBOs handbags, but the price paid would be far too high!:LOL:
 

magnil

Member
Sep 25, 2018
109
43
Sweden
Without wishing to appear too dim..... best best for a small magnet? The only place I can think of is a clasp from one of SWMBOs handbags, but the price paid would be far too high!:LOL:

Well I am in another country but guess you should have a shop that has similar magnets.

Neodymmagnet 12 mm 6-pack - Gadgets | Kjell.com

Mounted it with tape like this. Make sure you clean both rotor and magnet with isopropanol or similar.

Monteringstejp Instant Precision - CLAS OHLSON | Clas Ohlson

Option 2: Take it from the handbag and blame it on the dog ;)
 

Lad

Active member
Nov 15, 2018
114
102
Australia
Hi Bissona,

Before you start hacking it, I may point you out in the right direction.

I'm building a spare set of commuting wheels for my Focus Bold 2 and had the same problem of sourcing the rear rotor with the magnet. As you know the magnet is attached to the rotor (six bolt pattern) via special bracket. At first I thought that it would be a Shimano part, so I contacted them.

Shimano replied that this is a third party part made for Focus and Shimano makes the 160 or 180mm rotors with integrated magnet only in centerlock design.

So I've called an Australian Focus importer/distributor and found out that this part is stocked with Part Number 170 517 017, Bolt Pattern Magnet Holder and costs here around AUD10.00.

Unfortunately they won't sell directly to public, so I was advised to see my LBS and ask them to order it for me. So if you find out your Focus distributor, call them and see what they say.

BTW in the end I ended up not getting this holder, because the six bolt pattern wheel I was looking at initially had really bad user reviews (aluminium where steel is needed). Got a good deal on Shimano MT centerlock 12x148mm wheel. Nothing fancy, but for commuting on asphalt with 2.4" Schwalbe Super Moto X on both wheels will do just fine.

It was a bit of a gamble as the spec said that hub can take 9 and 10 speed cassette only. Found the same wheel on one of the German online shops which said 9, 10 and 11. Then of course just ordered from CRC the Shimano centerlock rotor with magnet (AUD 77.00), and 11-42 XT cassette.

Fitted it all last night, the Germans were right. No problems, all works like a charm.
 

DAZ1925

Member
Nov 7, 2018
75
42
UK
It has a magnet mounted on a small bracket which in turn is bolted onto the disc via two on the disc mount bolts. It's not a spoke mounted magnet.
 

bissona

Active member
Patreon
Oct 14, 2018
137
106
Guernsey
We just picked a small round magnet up locally and glued it into place.

Funnily enough it came unstuck the other day but the magnetic force kept it on the carrier. Not sure I'd want to rely on it in the long term!
 


DeeJay88

New Member
Have just done the same brought a cheap wheel to ride on Pavement - went to a bike shop at 7pm (late night shopping) and they sold me 3 styles for $10 - One is in a plastic mount - sticky back with a step in and have Cable tied it to Disk but trying to get OEM spares also.

Is a Centre Mount Hub so have a 6 bolt Disk and running an adaptor will need to customise OEM magnet to get to fit - Brought a Cheap set of 29er wheels to use but the rear triangle just misses out with no clearance. I know they sell the Jam2 in a 29er can't believe for 8-10mm they would have to different rear triangles???? ?

Don't know what this one in Pic's is Off but seems to work is running about 2 mm further out on the PCD than OEM one.

Cheers David

IMG_0938.jpg


IMG_4681.jpg
 

glovemtb77

Member
Aug 2, 2020
28
16
80228
Don't know how all this turned out but just thought I would add I have the Shimano not rotor mounted unit with my E8000 system: SM-DUE10
From an engineering perspective, i think it is a bad design to mount anything on a hot ass rotor unless it is screwed on/in iow metal mounted.
One could have gone to this other system referenced above simply because again, gluing a magnet to a rotor that gets really hot may lead to a really unpredictable loss of magnet eventually....somewhere after a 30 minute descent...(Kinda like gluing tiles to a Space Shuttle....well.) Anyway, for my other wheelset I got an almost identical spoke magnet that was much cheaper (4 bucks) than the SM-DUE10 magnet and put on the spoke. But just in case I took the OEM magnet off my original wheelset and took it with me for a couple hour beta test. Absolutely went great until one steep uphill about an hour in. ONE W011 error is all you need to ruin your whole day on a steep technical climb with a heavy e-bike crashing down on you (it didn't I caught it but had to push the rest of the way up the hill.) By the top of the hill the system had reset and was fine the rest of the ride.? But again, screwing around with non-oem works great till one W011 error....so smart money (I purchased 2 more OE magnets at 12 bucks each. One for my other wheelsets and one to carry on bike as a spare.) I don't like either solution all that much rotor or spoke but I will leave the rotors alone for now. Seriously, we pay allot for these bikes. So worth it in this case and I am one of the cheapest guy on the planet. ?
 
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