Strange movement at motorway speed!

[Superams]

Hi all hope were doing ok, frist post so please be gentle and hopefully someone might be able to help.
Whilst driving at speed say 60-80mph on the motorway when I let off the accelerator the car twitches to the side slightly not enough to run me off the road or anything but still a definite movement always to the same side.
I took the car to a BMW indy and they had it for a few days but couldn't find what was causing it but they checked the suspension, dampers, bushes etc. I had the diff oil changed with them at the time, they recommended a wheel alignment which I subsequently did and all ok just some minor adjustments but still the issue happens.
Any help would be greatly appreciated or has anyone had a similar problem.

[Blaxwil]

Does this occur on the same stretch of motorway? If so, it could be small grooves in the pavement that sort of binds up with the thread in your tires.

Do you have spacers?

[M5Rick]

Twitches to the left?

[JW_ATL]

What tires are you running and about how old?

[Superams]

Hi,
It doesn’t matter which road I’m on, it does it whenever at motorway speeds.
No spacers everything all standard.
Yes it feels like it twitches to the left!
It’s on Dunlop GT sportmaxx and have about 4mm all round.

[JW_ATL]

Originally Posted by Superams

Hi,
It doesn't matter which road I'm on, it does it whenever at motorway speeds.
No spacers everything all standard.
Yes it feels like it twitches to the left!
It's on Dunlop GT sportmaxx and have about 4mm all round.

What you describe happening sounds like tramlining. May be time to try new tires since your at 4mm anyway and due soon. I've definitely had this happen on vehicles with specific tires and wear.

[M5Rick]

Lots of us on here go for the Michelin Pilot PS4S which are superior in grip even more so than the previous super sports and it's fair to say they are more stable under extreme use.

[Superams]

I’ve actually got a set in Michelin’s in the garage ready and waiting just getting the last bit of wear out of these first.
Would the tyres really make that much of a difference? I did think this but I’m no expert, I suppose it would eliminate another thing to check.

[M5Rick]

Originally Posted by Superams

I’ve actually got a set in Michelin’s in the garage ready and waiting just getting the last bit of wear out of these first.
Would the tyres really make that much of a difference? I did think this but I’m no expert, I suppose it would eliminate another thing to check.

I wouldn't wait and throw them on now. If they're new or decent tread used then you'll notice the difference. Some of the forum members and myself have fitted 305.30.20 on the rears instead of 295's and there's far less 'chirping' on take of though with colder weather you can expect summer tyres not to work as well as when it's warmer.

[Superams]

Yes think that’s the next step for me, I will get them fitted ASAP, and hopefully will sort it.

[celicatoe46m3]

Sorry this seems to be exactly what I experienced as well. I had this diff oil change recently but on my old tires it was happening. Like a sudden shift at highway speeds. I had new tires replaced and it happens once in awhile as well.

A bit freaky. But if I dont pay attention, I think I could hit a barrier....

Nothing from suspension indicates any issues.

[WolfBLK]

I had this happen on my 2022 Benz S580 when it had around 10k miles on it. Come to find out something knocked loose and the alignment was off. After 4 wheel alignment everything was back to normal.

[M5Rick]

Originally Posted by celicatoe46m3

Sorry this seems to be exactly what I experienced as well. I had this diff oil change recently but on my old tires it was happening. Like a sudden shift at highway speeds. I had new tires replaced and it happens once in awhile as well.

A bit freaky. But if I dont pay attention, I think I could hit a barrier....

Nothing from suspension indicates any issues.

Check for splits around the circumference on the inner walls of the rear tyres even if they were replaced.