mazdaspeed7

A few weeks ago, my car was fine. I got 2 new tires for christmas, and got them mounted and balanced middle of Jan. Since then, my car has had a very violent shaking between 45 and 60 mph. It is had enough you cant hear the radio, cant have a conversation, and get a nice massage from it. I put the stock tires back on(2 were rebalanced with my new tires), and it doesnt help any.

First, I know my tires were balanced with the machine set on 6.5" wide rim, but my rims are actually 6". Could this be causing all of my problems or is it likely something else too. The shaking is really bad.

One more thing, I know one of my CV joints is on its way out, its starting to sling grease all over the bottom of the car, and it has never been rebuilt as far as I know(the boot is getting very dried out). I am getting these rebuilt soon, but I wanted to fix the vibration problem first, unless the CV's themselves are causing it.

Xentrix

Wheel bearings maybe?

grab a wheel and give it a good tug, if it moves or makes a sort of clunk sound they are loose.

7'sfalife

I dont know if this helps much, but I had a simular problem with my car except mine started shaking around 60mph. All I knew was that it was for sure coming from the rear so I took a peak up under and found that my lateral link was just floating around, The bolt that holds it into place actually snapped in two. The only way I noticed it was when I tried moving all the suspension components to check for loseness and it popped right out. This could or could not be your problem, just given ya my $0.02.

mazdaspeed7

The wheel bearings are for sure good, and there is NO play in the wheel bearings. I looked the suspension over really good the other day, but I didnt manhandle anything to see if it is not acting right. Ill do that tomorrow. There arent any loose bolts or anything like that.

Im not having any weird handling, like the lateral links being messed up, perfectly predictable, no unsteadyness, etc.

Scott 89t2

swap your front and rear wheels around. it's free
if it gets better or worse then it's the wheels/tires. it it stays the same it's probably something else.

hurleyboi514

could be the driveshaft. our truck at work had the same problem. i pulled the drive shaft, and we had it balanced and rebuilt, and it went away. it only happened between 35-45 mph.

mazdaspeed7

Alright, I have 6 wheels with tires right now. 2 have brand new tires, just mounted and balanced in Jan. @ more were rebalanced at the same time as I got the new tires mounted and balanced. The last 2 are old tires, not rebalanced. The last 4 tires were on the car before these problems, but 2 were rebalanced with the new tires.

Moving the tires aroung changes the vibration, but does not make it better. It just moves it around some, in relation to speed. I am really suspecting bad balancing due to the wrong rim width being specified.

Felix Wankel

If they use the wrong width, the machine will tell them to put the weights in the wrong spot.

mazdaspeed7

Possibly bad U-joints? Ill get that checked out.

hurleyboi514

yeah, i think thats what was wrong... you cant rebuild the Rx7 u-joints though, you have to get an all new shaft. if it turns out thats whats wrong, i have one, if you need it...

Dak

I have a similar prblem with two tire I put on the rear in Jan.Start vibrating at 45 stops around 70mph.fri. made the 3rd time I've had them balanced and all it seems to do is shift alittle.The tires are Yokohama A520's.Going to put some old BridgestonesI have on and see if it quits.It's driving me crazyDoes it worse when it's cold..Sorry I couldn't help you .

Felix Wankel

One thing I had to do when balancing 18-wheeler steer tires, when they wouldn't balance right, was to break them back down and spin them 180 degrees on the rims and rebalance them. Worked most of the time.

mazdaspeed7

New tires come with a mark that is supposed to be lined up with the valve stem. It makes it much easier to balance, and takes less weights to balance. And I helped install the tires, and I KNOW they were installed right on the rims.

I watched them be balanced 3 times in a computerized machine, but the rim width was put in wrong(partly my ignorance). It was put in the machine as a 6.5" width, but it is really 6" width. I think that threw it off. Im going to get my tires balanced correctly with the correct rim size tomorrow. Ill post the results.

tweaked

iTrader: (4)

since the vibration changes when you move the tires, It is definetly your wheels or your tires. your tires may be out or round. this happens sometimes with shipping because they are tied with wire so that they can be shipped and take up less space. they swish the tires. if they sitt to long is destorts the carcass perminatly. have them rebalance them and tell tham to watch for out of round. also tell them to make sure the wheel are not warped. when they put it on the machine, have them watch the wheel first with a stationary object as reference. like a wrench laying flat on the machine next to the spinning tire. if okay then you step back and watch the bottom of the spinning tire to make sure is has no variance. (looks like it is hopping). that .5 inch difference in the width will not make the weights off that much. I used to work for a shop that did tires too. this is where I started, tire man

mazdaspeed7

Like I said, I have 6 tires on rims, and only 2 are new. With those not on the car, it still shakes as bad as when they are on the car, but its just a little different. I watched my tires being spun on the machine, and the 4 that were balanced(2 new, 2 old) all apeared out of round, but now I think that may be from improper balancing more than the tire truly being out of round. I am going tomorrow and having them balanced again. We'll see how that goes.

Dak

I put an old pair of Bridgestones I have back on my car and it didn't change a thing.I guess it's not my tires.A freind of mine who is a mechanic thinks it might be my driveshaft going bad.He's going to take a look at it in the next day or two.I looked under the car and nothing is broken.

mazdaspeed7

Anyone else have a problem with the wheel weights not holding onto the rim? Ive had 6 fly off in the past month. I statically balanced my wheels yesterday, and they are all perfectly balanced. But one of my new tires is out of round. I know of a place that shaves tires, so that should fix it.

Is there any way to check the u-joints?

jarrod

to check your u-joints :
1-jack up your car and use jack stands!(rear)
2-with tranny in gear(std)park auto)
try and turn,wiggle drive shaft look at u-joints
for any kind of play.
3-listen for any kind of klunk sounds.
4- u-joints should feel tight when turning
shaft(tranny in neutral).
5-have some one turn tires while you
watch and see how much play the drive shaft
has.

hope this helps.....

jarrod

also my 7 just started doing the same as yours
this past weekend...
I will be tooling on it today trying to figure out
what it is......will let you know what I find....

jarrod

well I rotated tires and now the shaking is a little
better probably just need to balance mine....
I had them all balanced in december...
and guess what...............
now I noticed my throw out bearing is going out...
sqweeking, like crazy..........................
I put a new one in october when I installed
new tranny................

Felix Wankel

Also push up and down on the driveshaft near the u joints. It shouldnt move at all.

Icemark

Make sure that who ever is mounting the tires and wheels is not using an impact gun to tighten the wheel/lug nuts. Hand wrench, and not more than 90 ft/lbs.

On the later model (series 5) wheels they are very soft in comparison to the series 4 wheels, and if tightened incorrectly with a air impact gun they can be warped at the lug.

This would hardly show up on balancing as when they are balanced they are hub balanced not lug balanced, but would show up very easy at speed.

Turbonut

iTrader: (1)

I purchased a set of polished wheels for my TII last year. Had Nitto tires installed, which came off the factory wheels. No prior vibration. Balanced 3 times on a new Hunter machine...I watched, weights placed on inner and outer part of wheels to correspond with location on screen. Respun the wheels, perfect. Still a vibration 50-70. I even checked them with a dial indicator for run out. They were fine. They had a Hunter tech come in and balancer was found to be out of calibration. Had them rebalanced, no problems.

Dak

I changed my driveshaft yesterday.Problem solved.My car is vibration free now.My front U-joint was bad.

mazdaspeed7

It has been determined my u-joints are bad, and my CV joints are on their way out. Both are getting replaced this week.