[jondaah]

I’m getting a strong vibrations after 70mph. Most noticeable once I hit 85mph. The vibrations is more on the floor of the car, in an up and down motion, but it hits the steering too.

The vibration is so bad, I’m on my 3rd set of rotors in 6 months. Note I only have 30k miles on the M2 Comp.

Here’s what I’ve done already, with attention to detail and proper torque specs:

1/ rear shocks replaced (M performance were leaking so got KW V3 shocks only)
2/ new BBS wheels + tires w/ proper balance
3/ alignment at reputable racing shop
4/ new rotors + pads
5/ wire brush + brake cleaner everything for a smooth surface on hubs, rotors, wheels

Next:
1/ replacing Lower Control Arms (LCA) and Tention Struts (TS) with stock bushings

If this doesn’t work, I don’t know what else other than the steering rack. I have inspected every nook and cranny personally and with a mechanic. What makes me think it’s the LCA/TS is when I took the car to the alignment shop, he said my front left was way way off, jokingly saying that’s for drifting. Also, changing to lighter BBS wheels w/ more narrow tires helped too.

[HP Autosport]

You didn't mention it was while applying brakes or just cruising.

[jondaah]

Originally Posted by HP Autosport

You didn't mention it was while applying brakes or just cruising.

Cruising, not under braking

[HP Autosport]

Originally Posted by jondaah

Cruising, not under braking

If you have done everything else, a worn-out LCA or tension arm bushing could be the cause. We have seen it mostly with worn-out tension arm bushings.

What bushing or bearing are you currently running in your tension arm?

[jondaah]

Originally Posted by HP Autosport

If you have done everything else, a worn-out LCA or tension arm bushing could be the cause. We have seen it mostly with worn-out tension arm bushings.

What bushing or bearing are you currently running in your tension arm?

OEM. Only 30k miles but it is a 2019 M2C so might be possible.

Swapping them this weekend and hopefully solves it. Otherwise might have to look into tie rods and rack? Maybe the hub bushings themselves too?

I don’t get noises when driving or different vibrations when accelerating so I feel it rules out the driveshaft.

[HP Autosport]

Have you been able to check the front KW struts? You said it felt like an up and down motion.

[jondaah]

Originally Posted by HP Autosport

Have you been able to check the front KW struts? You said it felt like an up and down motion.

No leaks and i don’t see anything abnormal, but what should i look for you think?

[HP Autosport]

If the struts aren't providing proper damping, you could get some vibration because the inability to keep the tires in contact with the road. You might have to remove it from the vehicle for a closer inspection.

[calvin07]

Op did you find a solution to your vibration problem? I have this too and was wondering if you were able to fix it.

[jondaah]

Still working on it. Doing the LCA and TS replacements this weekend. Will report back

[jondaah]

I was able to rid the vibrations at high speeds. Looks like it was indeed the tention struts or lower control arms.

Strangely enough, I couldn’t find stand out issues on the old LCA or TS. Small bits of rust on the TS and most ball joints, could be superficial.

Heavenly highway test drive !