Vibration

Voran · July 25, 2007

Am looking for potential causes of a 2 second cyclical vibration that's most noticeable at highway speeds of 75 - 85 mph that began around 16K (car now has 23.5K) on my 2006 IS350 that was purchased new in October of 2007.

Had the tires balanced and alignment checked to no avail. Took the Lexus senior mechanic on a ride to confirm the vibrations and he said I needed new tires since the old ones had some alignment wear and cupping. Last week I replaced all 4 of them with the new GY Eagle F1's and still have the vibration.

Have scheduled a visit next week for them to take another look at the problem.

The vibrations are barely perceptible at 70 mph but become irritatingly noticeable at 75 - 85 mph but don't seem to get any worse at much higher speeds. Have had it has high as 135 to and they almost seem to go away at around 110. They do seem to be related to speed but not linearly since the cycle seems to be about the same 2 seconds or marginally less at above 100 than at 75.

Anybody know of a TSB on this issue? Have similar problems? Got any ideas?

BostonKiller · July 25, 2007

Sounds like a balancing issue, but you took care of that already.

However, I was experiencing somewhat similar issues with my BMW and it turned out to be a control arm. Have your car jacked up and the suspension components checked.

Good luck!

CrunchySkippy · July 25, 2007

You probably need a rear-end alignment. You're describing the symptoms, as front end alignment issues appear at about 60 mph and disappear around 70mph. Rear end alignment issues appear around 70 and disappear around 80 mph (depending on a number of factors like wheel diameter, etc). The "shimmering" disappears once the wheels occilating out of phase with one another.

What throws me off is how slow it occurs. 2 Seconds is a longtime.

Lastly, cupping is due to overheating (usually due to under-inflation). Pump those tires up...especially if you're taking the vehicle to 80+mph!

bartkat · July 26, 2007

Before digging too deeply into the suspension and/or driveline, get your wheels checked to make sure they are true and round. One small ding on a wheel can cause much problems.