High speed vibration

[Saff]

OK, I have a problem with vibration at about 60 mph and above.I’ve had this since I bought the car about a month ago.
It feels like wheel imbalance but nothing can be felt through the steering wheel, more through the seat of the pants. It’s not too severe but irritating.
I had 2 new tyres on the rear when I bought the car and have had all four wheels balanced. I’ve had all the wheels off and scotchbrite the disc and wheel mating surfaces so are all clean and flat. I’ve rotated the hubs whilst observing the pads and nothing untoward there.
Wheels back on and evenly tightened and torqued. Test drove and a slight improvement but still there. I checked each wheel for runout with a makeshift dial gauge on the outer rim, all seem fine but cannot check inner rim. I guess the way forward is to get all the wheels professionally checked for true then onto a four-wheel alignment. I love the car but this is spoiling the experience.

Any advice and suggestions would be appreciated. Cheers Steve

[paulrstaylor]

The seat of the pants probably points to rear wheel issue - balancing or bent rim?

[steamship]

Do you know if they are the correct rims for the car? Specifically, does the centre bore match the hub, as this will cause a vibration at higher speeds?

As far as I know, I believe the CB on the D4s are 66.6mm, the D3s were 57.1mm, so if you had D3 rims on, then you'd get this vibration.

[Saff]

Thanks Paul. Yep I agree. I guess I could swap rears to front to see if the effect changes then that would narrow it right down?
I even thought about trying the space saver but that also may be away with the fairies balance wise plus I'm limited to 50 mph.

[Saff]

Thanks Steamship.

AFAIK they are the originals, 19 x9j 10 spoke Y. They fit snugly on the hub.

[Conan_the_Librarian]

Flat spots on the tyres may also cause vibration.

[Saff]

OK thanks Conan. Rear tyres are new and the issue was there before but well worth a re-visit to the tyre dealer to check.

[strummagnet]

Are all tyres the same tread pattern? Though I ran a D2 on mismatched tyres and it went along no problems at all.

Runflats can be a nightmare, the ones on my 5 Series cause this when the obligatory sidewall bulge occurs around 100 miles after hitting the many potholes on the roads

[paulrstaylor]

Originally Posted by Saff

Thanks Paul. Yep I agree. I guess I could swap rears to front to see if the effect changes then that would narrow it right down?
I even thought about trying the space saver but that also may be away with the fairies balance wise plus I'm limited to 50 mph.

Swapping front to back would help isolate the issue for sure

[Saff]

Originally Posted by strummagnet

Are all tyres the same tread pattern? Though I ran a D2 on mismatched tyres and it went along no problems at all.

Runflats can be a nightmare, the ones on my 5 Series cause this when the obligatory sidewall bulge occurs around 100 miles after hitting the many potholes on the roads

Hi Strummagnet, yep each axle set match