Anybody notice a slight vibration at around 80 and it is only if you stay at that speed. A little faster or slower and it goes away. It has been there since I first got the car and even changing to the FRPP handling pack did not change anything. I figured it must be a tire out of balance but I have had them checked and the alignment as well and all is good.

Here is the strange part though. During normal driving with traction control on it is only a very slight vibration. However if I have the car in sport mode it is much more pronounced and I can feel it through the steering wheel. I have yet to try it with everything off.

Just wondering if anyone else had a similar issue before I bring it to the dealer and they say it is my fault for changing the suspension or they cant replicate it. Of course it is not since it was happening with the stock setup as well.

 

Sounds like it could be related to the EPAS, without knowing all the factors involved. Correct me if I'm wrong, but the Sport mode tightens up the steering ratio, correct? If so, that's where I'd start my search...

 

That what I thought it maybe. But I do not know enough about it myself.

 

I was thinking the same thing today on the way to work. I usually drive 80mph on a stretch of highway that is about 15 miles long. I figured it was a wheel possibly out of balance.

19" Premium Painted wheels

 

I have the same wheels as well. Put it in sport mode on the way home and see if it makes a difference. Mine is much more pronounced in sport mode.

But I had the wheels checked and rebalanced by the same shop I have been using for years. They are very good even with hard to balance custom wheels and still the same. I dont think it is a balance issue. I even made sure I didnt have any of those little bracket things on the wheel bolts.

 

Newb Question...

How do I get it into sport mode?

Manual is at home

 

Foot on brake. Hit the traction control button 2 times quickly.

The display will show advancetrack sport mode. Or something similar to that.

 

I'll see what that does and report back.

 

Thanks

 

Yep thought it was just me or aftermarket wheel/tire not balanced great. O oh my first quark with the new car lol!!!!!!

 

Hmm I smell a possible TSB coming...

 

Have you asked the tire place to road force balance the tires or have them swap the rear tires for the front, assuming they're the same size? It could still be a tire/wheel problem.

 

I guess it could be. But why would turning on sport mode make it worse? that is what doesn't make sense.

 

An article I read (may have been in Motortrend, not sure) they said that with TCS on, the electronic steering will actively dampin anything that causes the steering wheel to shimmy. Things like a slightly out of balance wheel, a crown in the road, slight bumps in the road, etc... But when you turn TCS off or turn on Sport mode, the electronic steering no longer dampins anything. So if there is a slight shimmy with TCS on, it will feel worse with TCS off.

 

Interesting. I guess I will have to rotate my tires and see if that helps. I have changed the whole suspension setup and the shimmy was there before and after the change. And all my tires were in spec but rebalanced anyway.

I wonder is it possible for a rotor to be unbalanced?

 

Dude, I thought only the Brembo cars had "Sport" mode? Are you saying your car has that? Because if you do, then I should too (same wheels).

I haven't spent enough time @ 80 to give you any input on your original topic.

 

It was my understanding that all the Premium cars have the Sport mode...it's just retuned to be less intrusive on cars with the Brembo and V6 Performance Packages. I thought that's what I read on here.

 

With Traction Control On...

Car Stopped, Engine On, Foot On Brake. Car has to be in normal TCS/ESC On Mode when you start to enter any of these modes. ie you cant go from TCS Off to Sport Mode.

Your car has it. My 2011 GT Base with 18" All Seasons has it.

1. Punch TCS Button Once - Turns TCS Off. (Message in Info Center). This is the only one that can be entered without being stopped with your foot on the brake.

2. Punch TCS Button Twice Rapidly - Turns Sport Mode On (Message In Info Center)

3. Punch and hold TCS Button for over 5 seconds - TCS Off / ECS Off - (Stability Control Off Message in Info Center)

 

All 2011 GT's have it including Base. Im not sure on the V6.

 

Gotcha ...I am pretty sure the V6PP has Sport mode too, but not sure on Base/Premium non-PP V6s...