Rear brake pad issues again

I've recently posted this in the RS bit but as the rear brake is the same twixt models I'm more likely to get a response here where the majority will visit.

I've had a right saga with replacing the rear pads on my R1200RS. I'm looking for a definitive answer to something that really should be plain and simple.

I've owned the bike from new, over 6 years. I love it. I'm doing all my own servicing.

This goes on a bit but it does get there in the end.

Back a good few months ago, at 30,000 miles the rear pads were getting worn and its a simple enough job. I bought Ferodo sintered pads and popped them in after cleaning the calliper that is maintained regularly. The OEM pads have a backing plate on the inside pad. The plate is a sheet of white plastic (PTFE?) encased in a stainless steel holder. I thought 'do the new pads need this fitted or not'? I checked around and no-one seemed to know. So I fitted it anyway and all seemed to go together fine in the workshop.

Then the saga started. Binding, overheating, rapid wear. I had the calliper apart a number of times, I even ended up putting new pistons and seals in and new pin grommets. 3,500 miles after I replaced 'em the inside pad was worn almost to the metal. I replaced the pads again with £50+ OEM ones that came with a new backing plate. Things are getting expensive.

Now the binding and odd wear has gone but I realise that the inside surface of the disc has taken a hammering and the new pads have worn unevenly to suit.

I'm about to fit a new Brembo disc and I have Brembo sintered pads to go with it. I've come to the conclusion that I shouldn't have fitted the backing plate to the Ferodo pads and that this error has caused me endless hassle.

I've spoken to Steve at Rainbow Workshop and he tells me that he only uses Brembo replacement pads and that he does fit the backing plate!

So that's Brembo with but Ferodo without? How are the punters supposed to know?

Has anyone else had this quandary and can they shed some light on it.

Failing that I'll fit the Brembo with and remove it at any slight hint of binding.

Peter

Hi Peter,
Just to clarify, you are calling the "inside" pad the one on the RH side of the bike looking FWD, is that right?

If so, having more wear on that RH pad doesn't really have as much to do with the pistons as with the FWD guide pin between the backing plate and the caliper body.
Front brakes=fixed calipers/floating rotors and the rear brake is fixed rotor/floating caliper.
When it get almost "any" wear showing on the steel pin, then the inner alloy bore of the caliper body is worn even more...since it is softer than the pin.

Now, anytime the brake is applied, the torque from the caliper pushing FWD causes the pin/bore alignment to get worse and worse, until it hangs up frequently enough to stay in a bind with the RH pad dragging/heating the rotor/wearing prematurely.

One more thing, I have a 2017RT, but I think this is the OEM spec across the different body types...in the Riders Manual, under Technical Data, the section for Brakes specifies the front brakes should be Sintered metal, and the Rear should be Organic. Not that this has anything to do with the rate of wear on the RH pad that could be from a binding thrust pin, but I wanted to point out what the book says.

That’s interesting about the pin/calliper wear and subsequent bind, thanks. I’ll have a look at that. I understand the brake calliper dynamics well. Things were all good until I replaced the pads and I’m fairly certain that the Ferodo pads were thicker and not designed to have the backing plate fitted. Not that I realised that until I bought OEM pads some months later.
Whereas the Brembo pads seem to have significantly less meat on them.
The OEM pads were sintered.
Do the OEM RT pads have the shim/backing plate do you know?
I’ll check the fwd pin wear when I go back in The wear on the inside Ferodo pad was excessive but not indicative of misalignment front to rear.

Yes, the RT rear pad on the RH side has the thin white pad and the stainless steel plate.
The misalignment of the caliper is so minor that it might not show up as tapered wear from front to rear, but just keeps the pad in contact with the rotor and causes it to drag and wear the full pad surface.

On my last RT (2016), I detected some wear in the FWD pin and the only way to resolve the problem was to buy a replacement from a low mileage bike and swap out the caliper and mounting plate. Solved for me at 75k miles...then I was rear ended and the bike was totaled at 78k.
Good luck chasing this down, brake issues are a pain in the back side!

Thank you. Very helpful and as you say, a pain in the arse indeed

2017 GSA. In December the dealer did my MOT and general inspection and reported low rear pads. I thought this was odd as they were only replaced 6K or so ago and I hardly use it so it’s only really used from the link of the brakes. Anyway I changed them. I got EBC Organic and I did refit the plate and lining. They are fine so far. (The old pads were only half worn as it happens but that’s dealers for you huh)

Having read this I will keep an extra eye on it.

Thank you.