Hey guys,

I normally cruise highways around 80MPH, so I always feel this very soft, but noticeable shaking at exactly 76MPH, and again at 87ish MPH. The shaking is very very subtle at 75mph and 78mph, but is very noticeable at 76mph.

Car has 135k miles right now. Tires are fairly new, < 20k miles on them. I rotate every 5k-8k miles, and balance as well. I also get an alignment check every 10kish miles. I have new OEM front shock/struts from around 80k miles. I have changed the engine/trans mounts since one of the engine mounts was shot at around 100k, along with the control arm bushings.

I'm not entirely sure what to look for when trying to diagnose this. I try to do all my work on my own, but the tough part for me is the diagnostics. If you know what's wrong, anyone can turn a wrench haha. I just don't have enough knowledge to figure out exactly what might be an issue.

Can someone help me checkoff a few things that could cause this?

 

sounds like a wheel that may be bent/damaged. My 760 would do the same exact thing and tire shop found a minor bend in the front rim. They threw the full size spare rim on the front with the tire from the bent rim and vibration gone. Let that rim sit in the trunk until needed.

 

Huh. Interesting. Back when I replaced my bushings I had to get new tires shortly after because they were visibly "bumpy" up front due to uneven wear pattern. I though that was due to the vibration caused by the bushings. Maybe it was amplified by something off kilter with my wheels too.

Will take a look Thanks. Any other suggestions from anyone?

 

Hey, did you ever figure out the issue? I have the exact same problem identical to the speeds you listed. My mounts are good, im lowered on tein but this problem existed before i lowered the car. my prop shaft is new as it had the whining noise and i had it replaced with a new one from acura. I just recently upgraded from the tech package 18's to the advance/elite 19's with brand new michelin pilot sports, balanced and have an alignment. thought by now the problem would have been gone but it still persists. im at a loss. all my mounts are good, bushings are good. just replaced links all around. vehicle has 289,xxx km on the dash. the problem does seem to go away after a long trip. itll start off bumpy and smoothen out once warmed up but still there a little bit. my mom lives 200km away one way and i can tell everytime i go to visit her thats what happens. brakes dont pulsate or anything like that either. planning a trip to florida from toronto in august, trying to take care of this before then. any help would be much appreciated.

 

I'm thinking it's an axle. You can disconnect one of the rear wheel speed sensors and disable VSA to eliminate the rear wheels. Being lowered certainly does not help with the issue as the axle cups have worn along with bearings.