I need to mount my speedo magnet somewhere convenient and was thinking of sticking it to the propshaft (don't want to stick to front wheel or front hub as it's much harder to mount the sensor in those locations).

Question: where do I want to stick the magnet? Should I place it on the flange or on the main circumference of the shaft? Or does it not matter? It's a single magnet rather than a set of 4 so I was just wondering if it would affect prop balance - but it is very small.

Thanks!

I have a k-series engine and box and I mounted mine on the inboard part of my driveshafts. The magnet holds itself onto the metal. I just put a small puddle of epoxy resin over it to make sure that it does not fly off.
Being inboard does not effect the balance.
If works fine for me.

[Edited on 29/4/2006 by nitram38]

to count the 4 bolts of the prop.

It will give you more accurency and a better response..

and less hasle..

Tks

I've got a Smiths speedo and that has a sensor capable of reading the four flange bolts. Well capacle enough so long as the gap is less than 2mm!

The setup has been working fine for over a year but the speedo does float a bit at higher RPM. To fix that I'm going to fix magnets as well.

With magnets the system I just installed on a Radical front hub the gap requirement goes up to 20mm

[Edited on 30/4/06 by bimbleuk]

What i did was just drill a couple of holes a few mm deep and the same diameter as the magnet into the prop flange adapter, so the magnets sat flush in the holes, and epoxy'd in. This way they sit flush and even if only using one, it wouldnt upset the balance because you would have removed some metal to compensate (not that such a small magnet would be significant to balance I wouldnt think)

[Edited on 30/4/06 by ChrisGamlin]

Thanks. It's a live-axle so I can't use the driveshafts. Also, I don't think it can take a reading from just the bolts - ie. you must use a magnet???

I assume it depends on what type of sender you have, Im pretty sure mine needs magnets though.

If I was to just stick the magnet onto the prop flange or sprocket adapter, would it be better to place 2 magnets 180 degrees apart than just using one, for balance? Or do you still think it would be pretty insignificant? thanks!

I dont think it would make much difference balance wise, but you'll get a more accurate speedo reading if your gauge can cope with two magnets.

mine senders mounted on the rear upright magnets are fixed to rear outer driveshaft output, does away with all the calculations involving dif ratios (just need revolutions per mile x number of magnetsImage deleted by owner