Strange vibration
Thread Starter
Pro
Joined: Jun 2008
Posts: 610
Likes: 1
Strange vibration
I've had this 96 for a few years. I've only recently noticed this going on, but it's possible that it has always been there. It's only recently that I've been doing a lot of freeway driving.
There is a vibration of the wheel balance type which comes on at about 60mph and does not seem to have an upper limit. It isn't a huge vibration but it is annoying. The thing that makes this one unusual is that it is not steady. It is a pulsating vibration.
What I mean is that there is a period where you feel the vibration, then a period where you don't. You can see it in the hood - it shakes a little, then stops. This repeats at approximately one second intervals at that speed. The faster you go the faster it repeats. I also seems as if I feel it in the steering wheel, then the seat, then nothing, as if it travels from the front to the rear, then takes a short break and starts over. It's very consistent in the way it feels.
I have a theory but I'd like to hear some independent ideas.
There is a vibration of the wheel balance type which comes on at about 60mph and does not seem to have an upper limit. It isn't a huge vibration but it is annoying. The thing that makes this one unusual is that it is not steady. It is a pulsating vibration.
What I mean is that there is a period where you feel the vibration, then a period where you don't. You can see it in the hood - it shakes a little, then stops. This repeats at approximately one second intervals at that speed. The faster you go the faster it repeats. I also seems as if I feel it in the steering wheel, then the seat, then nothing, as if it travels from the front to the rear, then takes a short break and starts over. It's very consistent in the way it feels.
I have a theory but I'd like to hear some independent ideas.
Racer
Joined: Jun 2006
Posts: 408
Likes: 0
From: Elkton MD
Pulsing pulse
Sounds like you have two wheels very slightly out of balance, likely one front and one rear. Due to the difference in diameters they will be in phase for a few seconds then out of phase for a few seconds. The closer the two tires are in circumference, the longer the phase.
If you've ever tuned a musical instrument to a standard tone by listening to the 'beats', it's the same phenomenon.
If you've ever tuned a musical instrument to a standard tone by listening to the 'beats', it's the same phenomenon.
Instructor
Joined: Jul 2004
Posts: 210
Likes: 0
From: Lakewood CO
I had a similar vibration a couple of years back on my '92 and found the problem to be a bad rear wheel bearing. You will need to check out the suspension componets to see if anything is loose.
Like others have said, it could be a wheel or two out of balance.
Dave
Like others have said, it could be a wheel or two out of balance.
Dave
Thread Starter
Pro
Joined: Jun 2008
Posts: 610
Likes: 1
Sounds like you have two wheels very slightly out of balance, likely one front and one rear. Due to the difference in diameters they will be in phase for a few seconds then out of phase for a few seconds. The closer the two tires are in circumference, the longer the phase.
If you've ever tuned a musical instrument to a standard tone by listening to the 'beats', it's the same phenomenon.
If you've ever tuned a musical instrument to a standard tone by listening to the 'beats', it's the same phenomenon.
I have had the tires spin balanced, but probably didn't get the best job. The tires themselves are not state of the art - Kumho. I bought them because I needed cheap tires at the time. Who knows, maybe they are the problem.
I don't think it has to do with bearings. The rears are new SKF and I just replaced one front that was slightly loose with a Timken. Plus I've done a lot of other work underneath. The car feels really tight and absolutely vibration free at any speed below 60.
So, maybe find a different shop and try the balance thing again?
Burning Brakes
Joined: Jun 2005
Posts: 1,188
Likes: 13
From: Wallingford Vermont
I've chased my share of driveline vibrations....
First: Have the tires "Road Force balanced" http://www.gsp9700.com/pub/search/FindGSP9700.cfm
Second: check your u-joints (in Neutral with parking brake off). Check your driveshafts (bent / damaged/ lost weights / unusual angles). Check wheel bearings.
Third: I've had engine vibes that you would swear where driveline
(injector that would squirt not spray) Don't rule out the engine, until you check.
First: Have the tires "Road Force balanced" http://www.gsp9700.com/pub/search/FindGSP9700.cfm
Second: check your u-joints (in Neutral with parking brake off). Check your driveshafts (bent / damaged/ lost weights / unusual angles). Check wheel bearings.
Third: I've had engine vibes that you would swear where driveline
(injector that would squirt not spray) Don't rule out the engine, until you check.
