My G shakes anytime i go 75 or over and considering i drive 120 miles every weekend this can get pretty annoying. I took it to the dealer and they said my wheels had to be balanced and while it did reduce it slightly it didn't completely. The car doesn't pull to any side, everything just shakes including the gas pedal area. Does this sound like an alignment job? because i took it to a tire shop and they said the issue wouldn't be the alignment... Also when i brake it also shakes yet the dealer said my rotors were fine
any help would be greatly appreciated!

 

Do you have stock or aftermarket wheels?

 

oh no ! sounds like the guy from G35Driver ...
I am running out of ideas of what my vibrations are caused by on highway - G35Driver

 

if you have aftermarket wheels then it is your wheels they are not perfectly round. if your on stock wheels then it might be your wheel bearing. I used to have the same problem and the dealer changed out the wheel bearings and the vibrations went away.

 

Like everyone is suggesting, if you have aftermarket wheels it could be those. Especially if you don't have hub rings on them. Do you have wheels spacers?

Are your tires worn evenly? What have you done to your car modification wise?

 

I do have aftermarket wheels and taken by the fact I don't know what a hub ring is then probably not. I'm not running spacers or any other suspension mods. What is a hub ring? and my passenger front tire, the outside edge is more worn than the rest

 

Then you probably need an alignment, need to balance your tires, and get a new passenger side tire....

 

Also check if the lug nuts are not lose or super tight........

 

It fills the gap between the wheel and hub. If they are a reputable wheel company, you should've received them with your wheels. This is a reason companyies ask what car you drive. Below should give you an idea of what they are and what they do. I'd be 75% sure that would fix the problem. They cost around $20 and should get them from whoever sold you the wheels. G37 Has a center bore of 66.1mm.
If that doesn't do the job, replace the passenger tire and go from there.

 

How do i determine the size of the one i need for my rim? and thank you very much for all the help everyone has given

 

Definately should get a set of hubcentric rings. You should go back to whoever sold you the wheels and ask for the rings, they will give you the proper size. It also sounds like you need an alignment if your tires are wearing uneven. I'd also suggest a road force balance, it will determine any defects with your tires that could cause shaking. Good luck.

 

^^^+1
The size you would need depends on the rim you have. The big hole in the middle that rests on your hub is called the center bore. Find the measurement online.

For example, if the center bore on your aftermarket rim is 73mm you will need a 73mm/66.1mm hub ring. First you need to find the center bore of your wheel. A quick Google search will probably help. 66.1mm is the size needed for G37 and most current Nissan vehicles.