High Speed Vibration

[MT930]

I am getting medium vibration at around 120 MPH not strong (Feels Rear Of Car), but very noticeable I don't like it. I am guessing it is a tire balance issue that is what I am looking at first I am having the tires re balanced. If that does not solve it, any idea's on what to look at next?

No vibration above 5000 RPM in 2nd or 3rd Gear, I don't think it's the fly wheel.

Michelin Pilot Sport Cup Tires with 1,700 Miles almost new.

[Flieger]

Yikes! That's a scary speed to feel unsure about your car.

Have you checked air/fuel ratios and timing? Maybe above 5000RPM the engine has gotten through a bad spot?

The rear is starting to get light at that speed due to aerodynamics. Maybe something to do with that?

[BReyes]

Have you looked at whether one is out of round? How about a front bushing? And BTW, yours is lowered right, and handled fine yes.

Hope you get up to speed soon

[javadog]

When they check the balance, have them measure the wheel runout. You might also throw them on a road force machine.

JR

[dentist90]

At that speed (200km/h) even the slightest bit of out of round will come into play. Most likely cause is a small flat spot in the tire or even a carcass flaw. I have a wonderful flat spot on my front right tire that is perfectly balanced, yet at 70mph it starts to feel like a vibrating massage chair. My mechanic buddy said it best..." you can balance an egg, but you can't make it round".
Less likely, but it could even be brake rotors out of balance.

[slw911SC]

Simple stuff first. May be loose lug nuts. Can't hurt to check.

[MT930]

Thanks on the suggestions, I will let you know if I can find it.