Rail speed sensor...

[Nick69]

Hi there, I've been having erratic speed readings and random stuttering lately so I've ordered a new speed sensor in advance if it finally packing up.
503 error showed its face yesterday so I'm preparing to install the new sensor and cable.
Anyone else done it..? It looks like it's going to be a pain in the arris.. Drop the motor and de-route the rear brake hose to make room for the grey plug end of the sensor to be internally routed through the holes in the chainstay...? Why do they make such a simple job so awkward..? Or is it easier than I'm imagining....?

 

[Driller_AU]

Never done this job but in my mechanic days with such a job i used to tie a piece of string to the old plug/wire pull it out, tie the string to the new plug and pull it back though carefully, hope this helps

 

[ddbros]

For some reason I've broken the mount holding mine twice now. I replaced the sensor the first time, super easy. Attach a string as you pull the old one through the stay so you can pull the new one through. Really not that big of a hassle. I've just super glued it this last time and seems to be holding up just fine. Do not apply much pressure on the mounting screw when you put it on. Seems like the plastic is really brittle. No need to drop the motor, just fish it down the hole.

 

[Nick69]

I think the main hassle is going to be cutting the rear brake hose and removing the whole caliper and hose from the frame bsfore I can remove and replace the sensor. There's no room for the grey connector on the end of the sensor wire to fit through the chainstay holes with the hydraulic hose going through as well.... We'll see how it goes... Cheers.

 

[Yoak]

Do you have a new bike or a new break disk rotor? Fist thing I would do before changing the sensor is taking off the magnet and check it for tiny metal shavings from the disk rotor. This has happened to me twice, and that caused the exact problems you describe.

 

[DeRailled7]

Do you have a new bike or a new break disk rotor? Fist thing I would do before changing the sensor is taking off the magnet and check it for tiny metal shavings from the disk rotor. This has happened to me twice, and that caused the exact problems you describe.

Agreed, i have to clean my magnet sensor regularly As well. It does collect steel shavings from the brakes causing erratic speed readings and triggering error messages.

 

[Nick69]

Yeah, I clean the magnet regularly.
Fiynd the cause anyway. Sensor wire was broken where it enters the motor area of the frame after it leaves the chainstay. They must have pinched it when I had my motor replaced a few months ago and its just been flexing with the linkage and finally gave up...
Thanks for your replies...

 

[Nick69]

Thanks for that detailed reply...
I managed to route the new sensor cable without dropping the motor. The pain in the butt was having to cut and remove the rear brake hose completely from the frame so that there was room to feed the grey connector through the chainstay access holes, no way it would fit through with it still there.
All done now though and working perfectly again...
Cheers all...

 

[gfunkmc]

Thanks for that detailed reply...
I managed to route the new sensor cable without dropping the motor. The pain in the butt was having to cut and remove the rear brake hose completely from the frame so that there was room to feed the grey connector through the chainstay access holes, no way it would fit through with it still there.
All done now though and working perfectly again...
Cheers all...

For future reference you can take the grey connector off and just pull wires through then put grey plug back on

 

[vertrkr]

I just replaced mine. I recommend lubing the wire and protecting the metal connectors. One of them got a little smashed pulling it thru the chain stay and it was really difficult to get it back in the grey connector.

 

[Peaky Rider]

I'm just about to change my sensor for the second time. I did the first one last year using the standard method and cutting the olive off the rear brake hose (the way my LBS does). Not a difficult job, just a pain.
I have done a temporary soldered repair on the current cable but not comfortable with this.
I will be giving vertrkr's method a go this time.

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