FAQ  r1.6


Reed switch and magnet



1.  Why do you recommend fitting the reed switch to the back wheel?


The "recommended" location for the reed switch is the rear wheel purely and simply because it's easier on most bikes, and will perform reliably


·          There's no technical problem at all with fitting to the front, though you will need extra length of wiring, and the routing the wiring is a little trickier than when fitted to the rear wheel.

·          There are some bikes where a rear wheel fitment is not possible, or very difficult - mainly single-sided swingarm machines like the Honda VFR, some Triumph's, Aprilia's and Ducati's




·          Most bikes have "solid" rear discs, as opposed to "floating" discs which are normally found on the front.

·          The carriers and bolts on floating discs run far cooler than those of solid discs

·          Magnets can lose their magnetism when subjected to excessive heat, which can lead to a loss of the signal

·          The solid rear disc carrier and disc bolts can get very hot when used on the track or coming down mountain passes.

·          If you ride in these environments, then it may be better to consider fitting the reed switch and magnet to the front wheel



2.  I already have a Sigma bicycle computer reed switch and magnet fitted to the front wheel. Can I tap into this wiring for the Pro-Oiler? 


You can use the Sigma's magnet, but not share the wiring. The reason is that the Sigma can upset the PRO-OILER  - and vice versa.

Whatever, you will still need to check that you have a good signal!



3.  Does the position of the reed switch matter? 


As long as it works, not really!


Tip: fix the reed switch temporarily in your intended location (eg. with double-sided tape), and test for the signal


But... there's always a "but"


·          The one real no-go is lengthwise relative to the magnet (so the path of the magnet is along the length of the reed switch). This can generate multiple signals

·          Even technically "undesirable" locations (like end-on to the magnet, pointing at the magnet's path like a proximity sensor) can work well. You just need to test it.


Some important points:


·          It's best not to place the reed switch on a surface which moves relative to the magnet, for example on the swing-arm itself.

As you adjust the chain,  the magnet may move out of range, resulting in a loss of signal.  Having said this, if you do mount the switch on the swing-arm, just check for a signal when you have adjusted the chain - or use a bracket with an elongated hole

Anyway, as you are using a PRO-OILER, you will not need to adjust your chain very often!

·          It's worth putting some thought into placement of the reed switch - there will often be more than one workable location. 

·          Think about how vulnerable the switch will be at wheel-change time. This is a major factor in deciding on a location

·          Look at Tips and Tricks and Troubleshooting for more reed switch and magnet information



4.  Does the position of the reed switch matter?


The magnet supplied is a powerful neodymium 6mm dia x 4mm high button (or 5 x 4mm depending on the bike model)


Many bikes have M8 allen head brake disc fixing bolts, and the ideal is to fit the magnet into the bolt head.

·          The magnet will stay in the bolt head without need for any form of glue 

·          To remove the magnet from the bolt head, use a magnetized screwdriver or another magnet


If your bike does not have M8 allen disc fixing bolts:

·          If it has M6 allen bolts (and you did not specify which bike you have at the time of ordering), PRO-OILER will post you a smaller 5x4mm magnet free of charge

·          If it uses conventional hexagon set-bolts, consider swapping one of the bolts for an allen disc mounting bolt.

There is no technical problem with this, however...

     Make sure there is enough clearance - allen bolts usually have taller heads!


·          Otherwise, glue the magnet to an aluminium bracket fixed by a disc bolt 

Do not glue the magnet directly to the brake rotor!

There is no glue in existence that can withstand the heat generated by a solid brake rotor. However, you may be able to glue the magnet to the disc carrier of a floating disc, as these stay much cooler.