Only necessary (but I think likely) if they don't meet minimum thickness spec:

For G35 Sedan:
Front
- Standard thickness : 24.0 mm
- Wear Limit : 22.0 mm
- Max uneven wear : 0.015 mm (measured at 8 positions)

Rear
- Standard thickness : 16.0 mm
- Wear Limit : 14.0 mm
- Max uneven wear : 0.015 mm (measured at 8 positions)

I looked this up because I have a bit of a braking judder myself and intend to inspect/replace the rotors.

 

I'm getting both. I have the vibration at speed which i assumed was that i just needed the wheels balanced, they are 20s and i have not balanced them in almost a year.
I'm also getting the strong shaking when I brake from high speed. Does not happen when I'm doing normals speeds, just high speed. AND sometimes the when I brake, the steering wheel tries to turn to the right.

I think i have some serious brake issues

 

Could one or all of the following:

1) Are the wheel centering rings the right size? Do you even have centering rings?

2) If the tires are wider than stock, especially in the front, the tires will be far more more prone to tramlining (ie pulling itself towards ruts, uneven road surfaces, etc). It's more apparant at higher speeds and braking.

3) Out of balance wheel/tire

4) Torn ply in the tire

5) Warped rotor

Seeing that the issue is more prevalent in the 65-80mph range, it sounds to me like a balance or centering ring problem.

 

that's the case of unbalanced wheel. after 80 it smooths, but, how does it feel when you hit 90-95? shakes more?

 

I have the exact same problem when i apply the brakes at a high rate if speed, also i have a slight vibration at around 60 mph. so a warped rotor is what could cause this?

 

from high speeds.. maybe ABS kicking in.

bigger wheel/tire combo> the abs is set to stock rims and tires. rpm,mph,ABS,steering,TPMS,braking distance are all affected.

pulling while braking..uneven brake pads/rotors, calipers stuck, brakes need bleeding,wrong brake flluid,suspension(alignment) problem.


other possiblities.

tire balance
worn tires
speeding

 

The fact that it's been a year since you've done any brakework tells me that it's probably the rotors. Ours are very prone to deposit buildup. Sometimes you can STAND on the brakes from about 90 to help it clear up, or try the usual "bedding in" process as you would do if you had new brakes. Other times not so much. I usually just spend the $120 or so and slap a new pair of front rotors on.

 

I guess its time for some new rotors then, because only my passenger front wheel vibrates when i apply the brakes slowly.