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I need to change the rear disc bolts as they're looking very tatty now. Does anyone know if these have to be mild steel for the speedo pick up or can they be changed to stainless jobbies?

Mild steel for the reason you suggest (well whatever steel they make bolts from - isn't it a higher carbon content or something?)

You wouldn't believe the number of people that go and fit stainless or titanium and then complain that their speedo isn't working .............

That was my reason for asking, probolt do stainless or titanium kits (not that I'm willing to pay £103 for a titanium set anyway! robbers)

I figured it would be a magnetic pick up so needed carbon steel bolts. I'll just order a set of OEM ones from some dealer, the head on the ones I have are rusted to buggery.

cheers d-rider.

check that the heads are the same as what you are replacing.... ask me how i know about domed head nuts chewing through the sensor....

Aladinsaneuk wrote:check that the heads are the same as what you are replacing.... ask me how i know about domed head nuts chewing through the sensor....

I did come across that story whilst searching for an answer. Sounds like my usual trick.

Been looking for a dealer to get them from, sickens me that most of them want £7.50 carriage to post 5 x screws to me.

Aladinsaneuk wrote:check that the heads are the same as what you are replacing.... ask me how i know about domed head nuts chewing through the sensor....

.... or doomed nuts as they were in your case ..............

Nooj is researching a 'fix' to allow the use of SS bolts here.

wayno wrote: I figured it would be a magnetic pick

Certainly not a magnetic sensor - I think it's a variable reluctance sensor.

D-Rider wrote:

wayno wrote: I figured it would be a magnetic pick

Certainly not a magnetic sensor - I think it's a variable reluctance sensor.

Uh huh. I was wit you up to "a"... Does it send up a pulse to the ecu or another form of signal?

I got that far too, but was too embarassed to admit it, electrickery is witchcraft as far as I can tell

Cathcart wrote:

D-Rider wrote:

wayno wrote: I figured it would be a magnetic pick

Certainly not a magnetic sensor - I think it's a variable reluctance sensor.

Uh huh. I was wit you up to "a"... Does it send up a pulse to the ecu or another form of signal?

Yes and No

It does generate a pulse but this goes to the instrument cluster not the ecu

Now we have identified something with a pulse that cannot run away, I do believe the hatless one's sex life is sorted .... Well till lambing is over at any rate

Didn't I read somewhere that the ecu only sends the speed signal every set time (ie 1/2 sec) as to stop the speedo jumping about? If not then I'm certainly away with it...

What wire colour?

Hoping there's an outcome to this as my rear bolts are a bit "furry" looking.

D-Rider wrote:I think it's a variable reluctance sensor.

I have an in-built one of those. I am increasingly (and variably) reluctant to get out of bed in direct proportion to the coldness of the external temperature.

Cathcart wrote:Didn't I read somewhere that the ecu only sends the speed signal every set time (ie 1/2 sec) as to stop the speedo jumping about? If not then I'm certainly away with it...

Nope - Firstly the ECU has NOTHING to do with it - the speed sensor is ONLY connected to the Instrument Cluster.



However, there will be a strategy to smooth out the speedo and stop the values jumping about - think of it as a sort of averaging