Runout, at least not 0.005" of runout, is not going to cause this "shudder". The more likely cause is either inconsistent friction characteristics along the surface of the disc or a thin or thick spot as you have noted.
You can rule out the thin/thick hypothesis by measuring the thickness at a number of points around the surface of the discs with a micrometer.
As far as friction characteristics, is it possible that some contamination ended up on the rotors? Could something have been spilled on the rotors that corroded them?
Thanks Jdub.
The rotors are new and clean. I do not suspect any contamination.
This morning, I measured both rotors with a micrometer. I believe my hypothesis is correct. The right rotor was consistent with measurements of .1990~.1993” around the entire rotor. The left rotor was inconsistent, giving me the following measurements as I went around:
Suspected low area (which is about the length the caliper):
.1982”
.1974”
.1972”
.1976”
.1981”
Suspected high area:
.1980”
.1985”
.1990”
.1990”
And the rest of the rotor as a went around:
.1987”
.1985”
.1985”
.1985”
.1984”
.1983”
.1983
.1986”
.1984”
.1986”
So I guess I’ll contact Murph and see what he thinks.
Any thoughts from the resident pros?
Ray