Car shaking/vibrating violently

[overst33r]

I just had the tires rotated and balanced, the wheels are not bent. Mechanic said bearings are still good.

Basically the car starts vibrating very hard once I reach 60 and then it tapers of when I hit about 80mph.

The vibration is coming from the driver's rear.

I am thinking it might be something with the axle...

Car is in sig.

 

[Pliablemoose]

http://www.miata.net/garage/65_mph.html

Very common problem on NA's, they're very sensitive to alignment & balancing.

And one of the perks of owning an enthusiast's car is everything has been done & fixed at one time or another and someone has posted it.

http://www.miata.net/garage/

 

[overst33r]

Originally posted by: Pliablemoose
http://www.miata.net/garage/65_mph.html

Very common problem on NA's, they're very sensitive to alignment & balancing.

And one of the perks of owning an enthusiast's car is everything has been done & fixed at one time or another and someone has posted it.

http://www.miata.net/garage/

I read about the 65mph shimmy, but I didn't think it would be that severe, the car really feels unstable...

OMG, I can't believe I forgot to mention: it comes from the driver's rear corner, even after rotation...

 

[Pliablemoose]

I'd spring for a 4 wheel alignment, should solve your problems.

Also, I've had my tires balanced before where they only put weights on the inside of the rim for aesthetics, it was so bad, I never made it home, turned around & had them do it over, butting weights on the outside of the rims too...

 

[overst33r]

Originally posted by: Pliablemoose
I'd spring for a 4 wheel alignment, should solve your problems.

Also, I've had my tires balanced before where they only put weights on the inside of the rim for aesthetics, it was so bad, I never made it home, turned around & had them do it over, butting weights on the outside of the rims too...

I had the guy check my alignment and the machine showed it to be good, I kind of expected this since the car does not pull to any side...

 

[Pliablemoose]

How many miles are on your car?

 

[Dudewithoutapet]

oh no, didn't you just buy that?!?!?!

 

[overst33r]

Originally posted by: Pliablemoose
How many miles are on your car?

83000

Originally posted by: Dudewithoutapet
oh no, didn't you just buy that?!?!?!

Yeah... It's ok though, things like this are to be expected...

 

[Pliablemoose]

I think the simple fix is to sell it to me

 

[overst33r]

Originally posted by: Pliablemoose
I think the simple fix is to sell it to me

I love it too much...

I actually just got back from Sebring Raceway today... that was fun to say the least...

 

[mrblotto]

I had a similar situation on my vehicle ('97 celica). It felt like I was constatnly going down a bumpy road, and the wheel would shake something awful at speeds. Turns out one of the rear struts was shot. Replaced them both and no more problem. Of course I have no idea what kind of suspension is in your vehicle but thought it worth a shout.

Good luck!

 

[exdeath]

So the problem didn't follow the wheel?

Maybe the brake rotor (or drum?) is off balance? Someone may have torqued it wrong or drove through some water after riding the brakes or something.

Have the alignment checked out. A bad bushing or loose toe link end or something could have the wheel wobbling in directions it shouldn't be.

 

[c3p0]

I'm not a mechanic, but I have never heard of an alignment making a car shake or vibrate. It would make the tires ware uneven, but vibrate???

Sounds to me like you have a bad tire and/or wheel. Or maybe something in the drive train. I don't think I would be testing it at 80 mph though.

c3p0
:beer:

 

[overst33r]

I don't think it is an alignment issue, since a bad alignment in my experience does not cause that much vibration. I think it is pretty safe to say that it is not a bent rim or bad tire since they were rotated and I have the same problem coming from the same area. If it were a bad rotor I would think it would vibrate under braking, which it does not. I don't really want to take it to a mechanic and have them troubleshoot what it is by replacing countless parts and running up the cost until they find what was causing it...

 

[exdeath]

Originally posted by: mariok2006
I don't think it is an alignment issue, since a bad alignment in my experience does not cause that much vibration. I think it is pretty safe to say that it is not a bent rim or bad tire since they were rotated and I have the same problem coming from the same area. If it were a bad rotor I would think it would vibrate under braking, which it does not. I don't really want to take it to a mechanic and have them troubleshoot what it is by replacing countless parts and running up the cost until they find what was causing it...

I'm just trying to think of anything involved in locating the wheel that might allow any kind of movement or cause wheel hop like symptoms since it's obviously not the wheel itself... unless they mixed them up and put the same one back on. It's it a smooth droning vibration or a bumpy shaky kind of vibration? I assume the latter since that is usually what is associated with a wheel being out of balance or a bad tire.

Maybe try a tire and alignment specialty shop where they can spin that one wheel up to 80 mph with a mobile wheel balancer while it's on the car and get under the car and probe around for anything.

I hate problems that only occur at high speeds, they are hard to replicate and track down in a garage.

 

[Fern]

Notwithstanding the tire rotation thingy, in my experience that's always been a tire.

It's happened to me twice. First time was just like yours, start at about 60mph, then stop at about 75 or 80mph. Had to get new tires to pass inspection and notice taht cured it.

This Summer had a similar problem even when going slow, again it was a tire.

Fern

 

[Don Vito Corleone]

Sounds like a bad tire. In any case, almost anything that causes severe vibration at speed is potentially dangerous and should be fixed ASAP.

 

[ValValline]

If you are absolutely certain it isn't the wheels/tires, then it could be a problem with the shock. Ran into this on an older Lexus SC300. We eliminated everything else on the car (control arm bushings, rack and pinion, tires/wheels, etc) The vibration was finally cured when we put in a new shock/stut.

 

[Capt Caveman]

Originally posted by: Don Vito Corleone
Sounds like a bad tire. In any case, almost anything that causes severe vibration at speed is potentially dangerous and should be fixed ASAP.

I agree. Could be that a tire or more are scalloped which is causing uneven wear. The problem could be an alignment or wheel balancing issue.

 

[overst33r]

Originally posted by: exdeath

Originally posted by: mariok2006
I don't think it is an alignment issue, since a bad alignment in my experience does not cause that much vibration. I think it is pretty safe to say that it is not a bent rim or bad tire since they were rotated and I have the same problem coming from the same area. If it were a bad rotor I would think it would vibrate under braking, which it does not. I don't really want to take it to a mechanic and have them troubleshoot what it is by replacing countless parts and running up the cost until they find what was causing it...

I'm just trying to think of anything involved in locating the wheel that might allow any kind of movement or cause wheel hop like symptoms since it's obviously not the wheel itself... unless they mixed them up and put the same one back on. It's it a smooth droning vibration or a bumpy shaky kind of vibration? I assume the latter since that is usually what is associated with a wheel being out of balance or a bad tire.

Maybe try a tire and alignment specialty shop where they can spin that one wheel up to 80 mph with a mobile wheel balancer while it's on the car and get under the car and probe around for anything.

I hate problems that only occur at high speeds, they are hard to replicate and track down in a garage.

Yeah, it is a violent bumpy shaky vibration. It's more annoying than anything because I have to drive 60mph for it not to vibrate and in the process clogging up the right lane. Or I could break the law and go 80... I usually do the former just because it is more pleasant in this particular case.

 

[exdeath]

Did it happen immediately after balancing or did it go away for a little bit first? Maybe a weight fell off or something easy.

 

[overst33r]

Originally posted by: exdeath
Did it happen immediately after balancing or did it go away for a little bit first? Maybe a weight fell off or something easy.

It was happening before the balancing and it did not change after balancing. The only thing the balancing did was make the car stable in low speed maneuvers.

 

[Epic22]

I would've guessed the motor mounts..?

 

[overst33r]

Originally posted by: Epic22
I would've guessed the motor mounts..?

Really? Why would a bad motor mount cause a vibration from behind me?

 

[PandaBear]

Shocks/Struts or axles. There are so much that can be affecting vibration on the same corner regardless of tires and wheels. Since it is 83k miles, it is about time to do shocks/struts anyways.