Wobble Sound

[ncnmra]

I'm getting a strange wobble sound. I'm having a hard time identifying where its coming from, but it is definitely speed related, and doesn't change during acceleration/braking. It is most evident between 40-70 km/h and pretty much gone at over 100 km/h. At first I thought it might be wheel balance or tire issue, but there is *NO* vibration in either the brake, chassis or steering wheel.

Any ideas? Could this be a bearing issue? I can't hear any "humming", etc.

[FORZDA 1]

QUOTE (ncnmra @ Jul 8 2009, 04:49 PM)

I'm getting a strange wobble sound. I'm having a hard time identifying where its coming from, but it is definitely speed related, and doesn't change during acceleration/braking. It is most evident between 40-70 km/h and pretty much gone at over 100 km/h. At first I thought it might be wheel balance or tire issue, but there is *NO* vibration in either the brake, chassis or steering wheel.

Any ideas? Could this be a bearing issue? I can't hear any "humming", etc.[/b]

Not much info here to go on, but as a guess, I would suspect the rear diff noise.

[ncnmra]

QUOTE (FORZDA 1 @ Jul 10 2009, 06:37 AM)

Not much info here to go on, but as a guess, I would suspect the rear diff noise.[/b]

Can you point me to more information on this? Is this considered part of the powertrain (and therefore the powertrain warranty)?

It sounds like tires to me, and one weekend I'm going to try to put my winters on and see if it persists.

[FORZDA 1]

QUOTE (ncnmra @ Jul 10 2009, 10:45 AM)

Can you point me to more information on this? Is this considered part of the powertrain (and therefore the powertrain warranty)?

It sounds like tires to me, and one weekend I'm going to try to put my winters on and see if it persists.[/b]

Yeah, could definitely be the tires. I can't remember where the thread is, but a quick test for the "common" diff noise is to pull the E-brake handle one or two clicks to see if the noise goes away. If it does, then the problem is likely the diff. When you pull hte E-brake, it shuts off the rear diff coupling....

[ncnmra]

QUOTE (FORZDA 1 @ Jul 10 2009, 09:35 AM)

Yeah, could definitely be the tires. I can't remember where the thread is, but a quick test for the "common" diff noise is to pull the E-brake handle one or two clicks to see if the noise goes away. If it does, then the problem is likely the diff. When you pull hte E-brake, it shuts off the rear diff coupling....[/b]

Thanks! Its funny, because I was JUST going to ask if that would be a valid test. As soon as I get in the car again, I'm going to try this.

[mick_estes]

^^ Yup, e-brake is a valid method to disengage rear diff. "one click of ebrake and whine stopped" was all Mazda Tech needed to hear before they authorized my dealer to replace my rear diff under warranty. New diff fixed the whine at 45-50mph but since then I developed another whine at 75-80mph.

On the tire front, you might consider swapping out the wheels (if you've gone aftermarket). At about 15k miles on my current tires, I noticed an significant increase in noise which was similar to what you described. I rotated - no change. I got aligned - no change. Swapped back to near bald stock RE050A and noise went away. Shop says it's due to the aggressive tread and the wear. Not sure if that's the reason but there's no denying the noise followed the wheels.

[ncnmra]

QUOTE (MEE @ Jul 21 2009, 04:35 PM)

^^ Yup, e-brake is a valid method to disengage rear diff. "one click of ebrake and whine stopped" was all Mazda Tech needed to hear before they authorized my dealer to replace my rear diff under warranty. New diff fixed the whine at 45-50mph but since then I developed another whine at 75-80mph.

On the tire front, you might consider swapping out the wheels (if you've gone aftermarket). At about 15k miles on my current tires, I noticed an significant increase in noise which was similar to what you described. I rotated - no change. I got aligned - no change. Swapped back to near bald stock RE050A and noise went away. Shop says it's due to the aggressive tread and the wear. Not sure if that's the reason but there's no denying the noise followed the wheels.[/b]

Thanks for the tips. I tried the e-brake test and there was no change. So I decided to take off the wheels and put on my winters just to see if there was a difference. I basically removed one wheel at a time. My first pick (rear passenger) seemed to be the culprit. I decided to do a tire rotation (cross pattern -- I have the non-directional P-Zeros), and it seems to have greatly improved. Oddly enough, it seems like the every so slight pull I had in the steering wheel is gone now too. However, it doesn't appear that the tires are wearing improperly (to my "untrained" eye that is).

The tires themselves have a good deal of road noise that they push through, but the "wobble sound" is now gone. I'm obsessed with it now, so everything I listen for starts sounding like it, but there is a 100% marked difference from before. I think that the tire/wheel I suspected is slightly out of balance (or out of roundness). I'll go for a few miles and see if it changes. I might get the wheels rebalanced just for good measure.

Thanks again for all the advise!

[mick_estes]

^^Glad it worked out for you. I forgot to mention I got re-balanced a couple of times with no change. I wish I could try to cross-rotate but my tires are directional. I think I'll have to tolerate the noise for another few months until it's time to get new tires. Fortunately, they grip like crazy so the road noise is easy to forgive

[HoustonSPD6]

QUOTE (MEE @ Jul 22 2009, 11:17 AM)

^^Glad it worked out for you. I forgot to mention I got re-balanced a couple of times with no change. I wish I could try to cross-rotate but my tires are directional. I think I'll have to tolerate the noise for another few months until it's time to get new tires. Fortunately, they grip like crazy so the road noise is easy to forgive [/b]

MEE - I am in the exact same boat as you. I am running on Goodyear Eagle F1 A/S. They grip like glue, but the entire car started to vibrate at about 13,000 miles on the tires. The best way I can describe the vibration is as if I had full motor mounts (I used to have all four at some point and I just kept the rear one). The vibration/noise seems to get worse at it gets hotter outside, and living is Houston it is realy realy hot these days.
I have some Sumitomo HTR ZIII on order, hope that will make it all go away.

What tires are you riding on?

[ncnmra]

^^^ If you're asking me, I have Pirelli P-Zero Nero M+S. I think MEE has the same tires as you (or similar) -- check out his sig.