REFLECTOR: Main LG vibration on braking ...

[Pat Shea]

I battled main gear vibration while braking in the
45-25 speed range on my XLRG for a while. I worked
with George at Matco trying all sorts of things, all
with little or no affect:

-Tried adjusting toe in/out
-Tried different pad material 
-Tried different calipers (upgraded to XT)
-Tried different discs (different material)
-Added line restrictors/dampeners
-Tried different tire pressures
-Balanced all three wheels/tires
-Shimmed away any disc run-out

I finally did what Scott Swing said to do early on,
which was have the surfaces of the discs ground flat.
I found a grinding shop (versus machine shop) that
charged me $20 to grind both discs. My discs were only
about .005 out and slightly bowl shaped (again, about
.005 worth). This solved the problem. I didn't do this
initially because when I sent my brakes to Matco for
inspection I specifically asked them to verify that
the discs were true - they said they were fine...

Pat   
 

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