Replacing rear rotor 1100

[Dave P]

1100RT with the 3 spoke wheel. Rear rotor is notched, old you get the idea. Pads are not completely gone but pretty close. Removed the rear rotor (it was pretty easy) have not put a new one on yet, will be buying one soon. I heard I need to adjust the ABS air gap or I might have abs problems. Is this true and if so what do I need to do to get it correct? Dave

[Michaelr11]

2 hours ago, Dave P said:

I heard I need to adjust the ABS air gap or I might have abs problems. Is this true and if so what do I need to do to get it correct? Dave

 

The gap is to the tone ring, not to the rotor.  More than likely, you'll install the new rotor and the ABS will successfully self test - if it was working prior. If it doesn't, there should be a label near the ABS sensor that shows the spec for the gap. Use a feeler gauge to determine if the gap is correct. If it is too close, you'll  have to add a shim. If it is too large, you'll have to remove the sensor and remove one or more of the shims.

 

 

[szurszewski]

3 hours ago, Dave P said:

Pads are not completely gone but pretty close.

 

I'm sure you are, but I just can't not ask: you're putting on new pads to go with the new rotor, right? 

[dirtrider]

Quote

1100RT with the 3 spoke wheel. Rear rotor is notched, old you get the idea. Pads are not completely gone but pretty close. Removed the rear rotor (it was pretty easy) have not put a new one on yet, will be buying one soon. I heard I need to adjust the ABS air gap or I might have abs problems. Is this true and if so what do I need to do to get it correct? Dave

Morning Dave

 

To add to what Michaelr11 said, check your motorcycle tool kit. The tool kit used to come with the correct feeler gauges for checking speed sensor gap. 

 

[Dave P]

Ok, I'll do more research into this. Yes abs was working fine and yes new brake pads. Of course I figured it would be remove parts, install parts. Not quite that easy.

[Michaelr11]

2 hours ago, Dave P said:

Of course I figured it would be remove parts, install parts. Not quite that easy.

It should be.  I’ve replaced my rear rotor at least twice, maybe three times. Remove parts, install new rotor, replace other parts and reinstall. ABS self check worked properly at first ride every time.  You could take the opportunity to also check the rear caliper. Two caliper slide pins hold the two halves together. Pull it apart and check the pins are clean and shiny, then put a little brake grease on each and reassemble.

[dirtrider]

2 hours ago, Dave P said:

Ok, I'll do more research into this. Yes abs was working fine and yes new brake pads. Of course I figured it would be remove parts, install parts. Not quite that easy.

Morning Dave

 

If you replace JUST the rotor itself then the original carrier/tone ring assembly should just bolt back on in the same place but it is still advisable to check/correct the speed sensor air gap. 

 

If you replace the entire rotor with carrier/tone ring assembly then it is a must to check/correct the speed sensor air gap before riding as any contact can ruin the expensive speed sensor.  

 

 

[Dave P]

I'm just planning to replace the disc and pads. I've got all of it apart and squeeky clean, like butter baby! I'll check that gap, hopefully won't have to get into switching out shims (that I don't have).

Might be the original disc- Ive never replaced it, bike has 133k on her but she had 95 on the odo when I bought her 10 years ago.

[szurszewski]

5 hours ago, Dave P said:

Of course I figured it would be remove parts, install parts. Not quite that easy.

 

It most likely will be. As D.R. said, if you're just doing the rotor and the ABS was working before, there is no reason the new rotor should impact the relationship between the tone ring and the ABS sensor. If you don't have the feeler gauges you could just install the parts, check to make sure there is at least some gap between the sensor and the tone ring when you spin the wheel, and then ride the thing. I have only replaced a few BMW brake disks (more than six but probably not more than 12?), and I've not had to adjust the sensor gap when I wasn't also changing the tone ring. 

 

You do - though - likely have *some* shims already in place, so if it's tight you may just be able to remove a shim or two - they fit under the base for the sensor and they look like this:

 

Edited October 17, 2023 by szurszewski
because my brain work not so good

[dirtrider]

6 minutes ago, szurszewski said:

 

You do - though - likely have *some* shims already in place, so if it's tight you may just be able to remove a shim or two - they fit under the base for the sensor and they look like this:

 

Afternoon szurszewski

 

If it's tight he needs to add shim or shims. Tight means the sensor needs to move farther away from the tone ring.  

 

 

[szurszewski]

44 minutes ago, dirtrider said:

Afternoon szurszewski

 

If it's tight he needs to add shim or shims. Tight means the sensor needs to move farther away from the tone ring.  

 

 

thank you for the correction!

 

I did remember that tight means too close ;) but I obviously was picturing the sensor not the way the sensor is actually mounted!