Originally Posted by
RowdyTI
Well, on one rotation of every rear wheel spin, I hear a noise, but the rotor is never touching the brake pads. That's not what the noise is coming from. I just tend to think with a big mountain bike tire, that some subtle wobble of the disc rotor is more normal than not even on perfectly new compnonents. If you have a mountain bike with a rotor that rotates perfectly straight when carefully inspected, I'd consider that a marvel and would like seeing a video.
Yes, I just had another look. The whole cassette on that rear wheel has some wobble to it. It has to do with how the wheel is spinning, which has that slight wobble. Again, I'm guessing this is more normal than not. Those of you with mountain bikes, does your rear wheel really rotate perfectly?
One says, "I have four bikes, 3 speshs, 1 salsa, all of them have a slight side to side wobble on the cassette when the rear wheel is freehubing. To notice it I have too look really closely when I have them on the work stand. I have not felt any issues due to this wobble while riding them. They all shift super smooth and quickly and never ghost shift."
Another: "I've not seen a cassette that doesn't do this, IMO they all do it to some degree as the cassettes floats on its bearings unless the pawls are engaged. Some say it's by design perhaps to aid with gear changes etc. I used to have £2000 road bike with custom built wheels that used to do the same thing, it never caused any trouble even after many thousands of miles riding. Unless it's causing specific issues I wouldn't worry about it."
One more: "My brand new bike with a cassette did this and when I got a brand new wheel/cassette, it also wobbled."
I believe this is directly related to the slight rotor movement I see even though the rotor looks perfectly straight.