Slight fishtail/waggle at 18mph

[algiorda]

My box seems to be fishtailing a bit. I thought it was my imagination, but I mounted my smartphone on a magnetic holder and at around 18mph, it seems to oscillate like the car has a slight waggle or what I call fish tailing.

Where should I check first? Tires (balance), rotors (warping), alignment (God knows)? At speed, the car does not vibrate and feels smooth (imperceptible). It is also smooth with no movement at Idle. The waggle seems to increase with speed.

[steved0x]

Do you get any clunking from the rear going over bumps? The rear trailing arms holds the wheel in position relative to the rest of the suspension, and if that ball joint is really worn out it could allow some movement of the wheel fore and aft, which changes the camber and toe. This toe change would cause the rear end to wander around like you describe.

Also if the rubber bushings on the chassis side of the lower control arm or toe arm are worn out, this could allow some movement.

Also a failed rear wheel bearing would allow the rear to wander.

Lastly, even just a bad alignment with toe out in the rear would give a wandering back end.

Any noises at all when driving, or any recent work done?

Steve

[911monty]

The first thing I'd check for is a bent wheel. Anyone else been driving your car?

[algiorda]

This vehicle is only 2 months old to me. The original owner took amazing care of this car for 26,000 miles. There is a gap in the service history for the next 26,000 miles. The tires look relatively new.

No noises at all when driving and at times seems really really smooth and quiet. Some times I think it's my imagination. I've ordered new pads and rotors and will start their and inspect the tires, then while the tires are off, I'll check my suspension see if anything is loose.

Thanks for the response.

[BYprodriver]

Originally Posted by 911monty

The first thing I'd check for is a bent wheel. Anyone else been driving your car?

Bent wheel rim won't cause what he is describing

[jakeru]

Wheel bent or tire out of round, gives some oscillation movement, mostly noticeable at lower speeds. A wheel out-of-balance condition will typically only show up as bad vibrations at higher speeds (and will worsen as the speeds increase).

Maybe start by making sure your lug bolts are all evenly torqued, and the wheel-to-hub surfaces are all clean?

Might try jacking up each corner, one and a time, also giving each wheel a spin, and visually observing to make sure the rim and tire doen't have gross run-out. If you identify one wheel with run-out, you've probably found your culprit. While you are at it, check your tire pressures, too. All this stuff is relatively easy to do.

Good luck!

[911monty]

Originally Posted by BYprodriver

Bent wheel rim won't cause what he is describing

I'll certainly disagree with you there. I didn't say dented, I said bent as in not true. You know like sliding into a curb. Yeah that'll cause the rear of the car to squirm at low speed.

[BYprodriver]

Originally Posted by 911monty

I'll certainly disagree with you there. I didn't say dented, I said bent as in not true. You know like sliding into a curb. Yeah that'll cause the rear of the car to squirm at low speed.

If he had slid into a curb I'm sure he would have noticed that was the cause & it would be obvious by simply looking at the wheel.

[Spinnaker]

Check the tires for a delaminated steel belt. Had a tire go bad once and it felt just like that. You can check the DOT code on the side wall for the manufacture date, anything over 6 years is suspect. Even if the tread looks good, an old tire can still go bad. It's not the amount of wear that matters, it's how old the tire is. Steel belted tires are notorious for going bad, you can see all the tire treads on the freeways from all of the failures.

[911monty]

Originally Posted by BYprodriver

If he had slid into a curb I'm sure he would have noticed that was the cause & it would be obvious by simply looking at the wheel.

Originally Posted by 911monty

The first thing I'd check for is a bent wheel.Anyone else been driving your car?

Sorry you're having a bad day. Please read my original post I didn't say the OP did it. Hell it could have been done by the PO during a last joy ride. The OP has only owned the car for 2 months, and this was an obvious example so you could understand a bent wheel. This could be caused as noted above by an improperly installed wheel, anything that would cause the wheel to not follow a straight line.

I am a big proponent of the KISS principal and have learned to NEVER take anything for granted. Always check the simple stuff before you move to the Advanced Philosophical Mechanical Engineering (ie expensive)

In closing I recognize and appreciate the knowledge you that you share and apologize to the OP for this useless exercise. I'm out.

[jsceash]

Did you check the car in the air for any movement. A failing control arm bushing or toe link might do this.

[nicecar]

flatspot or tire out of round? just a guess.... wasnt it a low mileage car