Bruno158

Hello- I just purchased two days ago (from an MB Dealer in Maryland) a 2014 S550 with 57k miles on it. Very clean one-owner car. Well, my first mistake was that on my test drive I did not take it on i95 and test at speeds above 60MPH. Below 60MPH, the car is a dream, as speed incrementally increases above 60MPH a slight roughness and vibration develops. Above 70 MPH it has a much slower response to acceleration. Please let me know any thoughts you might have that could be causing and what to do to fix? Thank You!

MJ50

moved to W222 forum...
try resetting ecu/tcu adaptations...

vincheung

You should have a 30 day (possibly 90 day warranty) if you had purchased from a dealer, so I would get back in there ASAP. Has the check engine light come on?

DreamS550

rebalancing all 4 tires.

cfmistry

Does it have 20” wheels? If so, my money is on bent wheels. Ask me how I know.

Fred2

Another possibility is the tires are flat spotted if it was sitting for a very long time.

Sactownmb

Best check for bent or cracked rims.

Nice Ride

What did you pay and what options did it come with?

Did you try road force balancing the tires?

Donnymac

Agree completely and before you spend a bunch of money, make sure you don’t have bent rims. A bent rim can be balanced but it can still vibrate like hell.

A wheel, brake, alignment or tire shop with an excellent reputation can get you started.

SW20S

It’s wheels and tires. I would have all 4 road force balanced and that will tell you if it has bent rims or needs new tires.

kafklatsch

Dont want to shift topics... but I had tires replaced at a Texas state wide chain and ask for Road force balancing... they told me they would only do it if they experience customer complaints after normal balancing...

I asked if they would do it anyway
Never did get a clear response

Fortunately the car rolls extremely well and smooth Already so I don't know if I actually received one...dont think i did... but i was puzzled at the reluctance...

cfmistry

It takes a lot of extra effort / time to do proper Road Force balancing. Although I am sure they charge more for it, it still probably isn’t worth their time. That being said, I believe it makes a big difference for those us who drive fast (100+mph).

SW20S

Never buy tires there again. Lazy ****s.

Expect to pay more for Road Force balancing, that I have no problem with.

Mitch Alsup

Yes, but before you road balance the wheels and tires, drive the car for at least 1 hour at 50+ MPH to put a heat cycle into the tires and get rid of any flat-spotting the rubber took on while sitting for months.

If you balancing before this, they will need another after a couple of heat cycles.

Donnymac

As all here are suggesting, a Roadforce balance is a good start. Just make sure the Tech is not a rookie which some are. Make sure they include with the balance a test for the tire and wheel each for being out of round. A smooth ride analysis is impossible without passing grades for these tests.

And at 8 years old, an S without a bent wheel is unlikely. Good luck.

konigstiger

Locate: https://www.hunter.com/wheel-balance...d-force-elite/