Hey, I'm pretty sure it's due to my rotor resurfacing, but want to be positive...

Could this be it? I don't remember this happening with my other set of brakes, but it could be something else that's wrong.

I let a guy at Murray's hand resurface my X drilled rotors, so I think that's the case.

It might be warped rotors, or something else. The rotors are easy enough to check with a dial indicator (on both surfaces).

Other possibilities might include improper bedding of the pads. See http://www.zeckhausen.com/bedding_in_brakes.htm for one bed-in procedure. Also an out of balance tire or worn suspension parts, especially control/thrust arms, can cause this.

Yeah the thing is I have a track set of rotors/pads and my street setup was these X drilled rotors and set of whatever pads that were on there from the PO, when I took the track setup off I decided to refinish the rotor surface and reused the old pads.

They stop fine at low speeds and high speeds, at 55mph though the sheering wheel will really shake violently.

Throw a dial indicator on them and check for runout.

It could also be a pad or surface finish problem with this combo. If there's a variation in surface finish it will cause a vibration under braking that can be magnified by any wear in the control or thrust arms. I've also seen a particular set of pads (brand unknown) cause this on a 735i that I once had. Since I had complete confidence in the rotors (as proved by a dial indicator) and was certain that there were no problems with the suspension or the tires , I replaced them with Pagid pads and the problem went away.

Because you say 55mph - which is the magical thrust arm speed - I'm just going to add that worn thrust arm bushings will GREATLY exaggerate the feeling of a 'warped' rotor. If yout TA bushings are old, you might consider replacing them.

Because you say 55mph - which is the magical thrust arm speed - I'm just going to add that worn thrust arm bushings will GREATLY exaggerate the feeling of a 'warped' rotor. If yout TA bushings are old, you might consider replacing them.

Good to know.