[R_don_abon]

Hi all,

I'm having a tough time getting this diagnosed.

At low speeds around 25mph (think slow traffic on the highway), I'm feeling like the car is kind of rocking or swaying. Eventually, at higher speed, it feels like a vibration no different than an out of balance wheel but at those low speeds, it feels like the whole car is just rocking. I figure it has to be something rotational so let me start with my wheels. I initially thought it was my new VMR wheels or the tires MPS4S as i started noticing after I put them on. I tried rotating for good measure to try to isolate which wheel it could be but no significant difference. The whole car just lumps along (i.e. not vibrating in the steering wheel). I've had one shop check the balance and all was good so seemingly not a balancing issue. That was soon after I bought them.

I dealt with it last year and just put them back on this season. I noticed one tire was leaking air right when I took it out of storage. Took it to a decent indi shop and they confirmed it was a puncture that couldn't be patched. They're replacing the single tire (the opposing side is basically new still so no need to replace the pair according to them). I'm hoping somehow that puncture was affecting it last year and a fresh tire might fix it. I'm also having them road force balance all wheels and check if the tire is out of round just to be safe. The shop didn't give me a very good answer when I asked them to diagnose it. They said this feeling is common in the 2 series..

If it's not the tire or wheel, is there anything else that could cause a car to rock like that? it's odd if the wheels/tires test out fine because I definitely feel this more on these wheels.

I think my wheel bearings are fine. No seemingly obvious issues with the rear axles (I checked for play by the diff). My only other ideas would be the diff itself or driveshaft unless I'm missing something obvious.

Anyone have any input?

[HP Autosport]

Are these hub centric or lug centric wheels?

Toss your old wheels and tires back on and see if the problem goes away.

[TTR M240i]

Are you using wheel spacers?

[R_don_abon]

I definitely don't feel the rocking motion with OEM wheels but was surprised that the first shop didn't have any issues with balancing them. No spacers and yes hub centric.

I got an update from the second shop I took them to yesterday. After their initial diagnostic, they said "this is normal." It's not. So I asked them to road force balance all four. They said that 3 of 4 wheels registered at a level 50 on their Hunter (tolerable is up to 20. The 4th tire was replaced due to a puncture and balanced at level 5. So the good news is they determined defects in 3 tires. The bad news is the warranty prices through Michelin is going to be a shitty hassle. Their approved shops are chain tire stores and I really don't want to take my car to one of those. I've had too many bad experiences and this setup is my first actual expensive set of wheels.

I won't know for sure if it's fixed until all tires are replaced so I'll update later. Fingers crossed for now.