Cobalt Friction Pads loose in caliper

[CanadianE90]

Anyone running Cobalt XR series pads in a stock E9x caliper?

When installing them we noticed they don't have the back clips like a normal street pad so they are a bit "loose". However, driving to the track they seemed fine. After the first session, they became incredibly noisy and are "bouncing around"

On track aside from the noise, they function amazing. However, it appears the pads lightly touch the rotors and are lifted inside the caliper everytime the rotor rotates and then when they hit the top of the cliper they drop back down.

It almost sounds like a broken from half shaft (not as loud of course). But even at highway speeds you can hear them bouncing around.

[roastbeef]

this won't hurt anything. my rear ap's don't have retainers and the pads shudder a little bit at parking lot speeds over little bumps. what you describe is normal.