Rear Brake Pads
 

Replace the rear brake pads and have a question. the old pads, which I assume are stock, as I have never replaced them and the bike had 5xxx mile on it when it came into my possession.
The stock pads had a thin metal backing plate clipped on the back of the pads. Do I transfer these to the new pads? The new pads are on and have a few miles on them and seem good.

Doesn't really matter. I doubt you would notice a difference either way.
Were the previous pads worn out?

Still had a lot of life left, but didn’t have much in the way of effect. Did a bleed on the system and didn’t improve. Deglazed the rotors and with the new pads it’s much improved.

Used to race EBC Endurance 3 hour races. The fast guy in our group of 3...Jan Eric Svensson, said that the only time he used the rear brake, he crashed.

Well, my skill level is, shall we say, is far from laser level (bought a laser level recently for a project, don't know how I have done without one all these years), more like Grand Pa's wooden level from the 1930's. You know the one with a single, very questionable, nearly impossible to read spirit tube.
A lot of places I ride have gravel and sand. On the shoulders of the road, intersections, parking lots, etc. This is the (high) desert after all, and that is what most deserts are made of. I find that if I need to slow or stop quickly from slow speeds on ass puckering surfaces the rear brake gives me a bit of a margin of error. Also in slow speed maneuvers, dragging the rear brake seems to work better (for me).

Comment was not meant as a dig. It was an anecdotal memory. Jan died of brain cancer about 5 years ago. He was from Sweden, an engineer, and had a very dry wit. It was a fond memory of an old friend.

I too use my rear brake.

As far as I know they are a noise reduction shims essentially. I reuse them but I also put a dab of caliper grease on both sides too. I also rely on my rear brake, sometimes heavily.

AV