rpmnospin

I have had this vibration that I can feel come through the steering wheel (and seat). I notice it most at around 70-75 mph while on the hwy and it comes and goes in cycles -- like: vibration count to 4 gone, count to 4 and vibration begining again, over and over again! I had my motor and trans mounts replaced yesterday thinking that was it, but it did not fix the problem. I have also replced tires (twice) thinking I had a cupped tire or something. This is driving me nuts! You guys have helped me figure everything else out -- what do you think?

Benz-O-Rama

Definitely sounds like a harmonic vibrations of sorts. Have you had your wheels checked for bends? Happened to me every time I've ever bent a wheel.

komp55

Front end vibration usually results from one of three sources: i) bent rim or out of balance whee/tire assembly; ii) worn suspension components; and iii) if the vibration is felt during braking, normally a warped rotor.

Since you've said your car's vibration occurs while you're driving, I'd start by eliminating a bent wheel as a possibility. To do this, find a tire shop that has a Hunter GSP9700 Road Force balancer, and have them dismount your front tires and then do a measurement of lateral and radial runouts of the bare rim using the GSP9700. Since new tires haven't fixed the vibration, I'd wager a problem with one of the rims. If the wheel runouts checkout within specification, you've eliminated the wheels as a vibration source. Have them remount the tires and then do a Road Force balance where you end up with a radial force measurement of under 20 (standard setting for P metric tires is 26). If the rims are straight and you can get a road force balance in the sub-20 range of road force measurement, you have conclusively eliminated your wheels/tires as the source of your vibration.

One other thought - are you using any sort of wheel adapters or spacers with your wheels? Adapters are notorious for creating vibration problems. Make sure your rims are hubcentric, or if your wheels require adapaters, make sure they are the correct size for your car's hubs and are not worn or damaged.

Eliminate the wheels/tires before considering other possibilities.

rpmnospin

Thanks guys! I don't use any adapters and no issues when breaking -- just hwy speed harmonics. Now that you suggest bent rim, it reminds me that about a year ago the dealer put 4 rear tires on the car. I picked up the car at night and drove it about 225 miles. They had set the TPS for 19lbs, the TPS did not go off at all -- but the next morning at my in-laws -- the front two tires were flat. Imagine that! Looking back on it I bet the rims got bent during that little episode. Oh well, that is the past -- I want the vibration stopped and it does get worse (or cycles faster) at higher speeds. I will check it out and again -- THANK YOU

jrcart

Check your wheel bearings too, they usually start as high speed vibrations that come and go at various speeds, as they worsen so does the frequency and severety of the vibrations.

URnext

If its not your wheels that are bent/balanced then my guess is that its front suspension since I had the same vibration you described but the only diffrence is that I also had this horrible squeak coming from the front suspension.

The stealership had to replace my Ball Joints, Lower Control Arm Bushings, Thrust Arm, and Flex Disc.

Hope this helps