Brake rotor unusual wear

[Rocketman]

OK, so a few weeks ago, I decided that my front pads needed to be changed.  I ordered some online.  I went out to the garage, and looked at them again, and decided that I ought to change them right away, and that I could scavenge them off of my old Valkyrie (my old Valkyrie was in my garage when a hurricane came through and swept 2 feet of seawater into my garage and left it there for a day or two.  It has been sitting for a year.  The pads on that one weren't new, but had lots of life left in them).
I pulled them, and put them onto the new Valkyrie.
While I was working, I noticed that the new Valkyrie's rotors looked very good, especially for almost 51k miles.  I put the pads on, then rode it.  Immediately noticed that my braking power was down.  I put ~100 miles of round town riding on 'em, then received the new pads.  I put the new pads on immediately, and noticed that the rotors, while not past the limits of usability, were significantly more worn than before.  The braking power had returned.
So, I have my own ideas, and I've heard a few others.  Without biasing the group with my own ideas, I ask for yours.  What caused the rotors (both sides, front) to wear significantly deeper grooves in 100 miles than had been worn by over 50k miles before that?

Mark

[Mr.BubblesVRCCDS0008]

Could the pads from  your old valk had salt in them from the saltwater and cause unusual wear? Or maybe harden the pads too much.

[Ferris Leets]

used pads are already grooved from the rotors.  So when you install on another rotor they were a lot on the high points and don't work very well until they were into the new rotors grooves.

[roadmap]

i would rebuild your calipers they could be sticking. the gasket set are cheap. did the  calipers move real easy when you pushed them in if you could not move them with your fingers there sticking causing premature wear on your rotors and wearing your brake pads out. it time to rebuild anyway.

[John U.]

Did you mic the rotors before you put on the used pads. Looks can be deceiving, a change in the color of the swept area of the rotors could make it seem like rapid wear has occured. Just a thought.
Salt is hard and abrasive but I don't think it would hold up to bake pad service, I think it would rapidly become dust.

[Rocketman]

Could the pads from  your old valk had salt in them from the saltwater and cause unusual wear? Or maybe harden the pads too much.

That's actually the leading contender, in my opinion.  Either salt, or some unusual hardening from a water soak.

used pads are already grooved from the rotors.  So when you install on another rotor they were a lot on the high points and don't work very well until they were into the new rotors grooves.

I'd go with that if it was only braking power.  The pads (even if grooved already) should get worn down to match the rotors, not the other way around.

i would rebuild your calipers they could be sticking. the gasket set are cheap. did the  calipers move real easy when you pushed them in if you could not move them with your fingers there sticking causing premature wear on your rotors and wearing your brake pads out. it time to rebuild anyway.

The change occurred dramatically upon changing pads.  From a subjective standpoint, it hasn't continued after changing to factory-new pads.

Did you mic the rotors before you put on the used pads. Looks can be deceiving, a change in the color of the swept area of the rotors could make it seem like rapid wear has occured. Just a thought.
Salt is hard and abrasive but I don't think it would hold up to bake pad service, I think it would rapidly become dust.

I did not.  I wish I had documented it better, but wasn't going to mic rotors that looked good.  All I can go on is memory, but I am convinced that they were nowhere near this worn with grooves prior to putting in the used pads.
As for the salt not standing up to brake pad-type use, I understand where you're coming from.  I just don't know anyone who's ever used salted pads before, so I have no data.  If it's only a surface coating, I'd agree that it would probably wear away rapidly.  If it soaked into the pad material itself, it might be with me for the life of the pad.