Steering shake at over 65mph

[omodos]

Hello to all, not that i am in the habit of doing this but i briefly let go of the steering wheel whilst doing 65mph and over on a straight stretch on the highway... the steering wobbles slightly, its not to the extent where i would have felt it whilst holding the steering wheel, nevertheless it bugs me,had an alignment done recently after rear bush and suspension work...and also had one tire at rear replaced after all this...you think it needed aligning again after rear tire changed? Make matters cloudier no idea if steering tremor was there even after alignmignent was done initially, just concerned the trembling will eat through my tires quickly........any feedback much apreciated

[Overboost]

Speed related indicates out of balance wheels and tires. I would inspect and re-balance the tires. Being that you feel it in the steering wheel, I would assume the fronts are out of balance but I would check all 4.

[omodos]

Ta for reply, can't feel the shake but saw it when took hands of steering wheel on highway...not responsible but highway was empty...n wanted to see if x5 pulled left or right, it was dead straight

[oldskewel]

I agree on the likely slight wheel imbalance. It must be pretty small if you can't feel it, but can only see it when hands are off the wheel.

If it's easier for you to swap some wheels yourself vs. taking it in for balance, and if your front and rear wheels are the same size, you might try swapping wheels front to back to see if the wobble goes away. If it is so slight on the front, you probably won't notice things at all when the unbalanced wheel is on the back.

And congrats on the straight driving x5.

[omodos]

Originally Posted by oldskewel

I agree on the likely slight wheel imbalance. It must be pretty small if you can't feel it, but can only see it when hands are off the wheel.

If it's easier for you to swap some wheels yourself vs. taking it in for balance, and if your front and rear wheels are the same size, you might try swapping wheels front to back to see if the wobble goes away. If it is so slight on the front, you probably won't notice things at all when the unbalanced wheel is on the back.

And congrats on the straight driving x5.

Good thinking, getting them all balanced won't be too painful tire repairs sellers every corner here, i would upload a vid of the shake but bit risky driving no hands and using the phone cam to record ....just wondering if the shake wobble being undetected whilst holding the steering wheel is serious enough to cause accelerated tire wear?
On a side note this evening went for gas, and checked tire pressures, first time since i took it to for alignment balancing etc up front 2.5 bar, and rear one side was 2.2 bar and the other 2.6...dont have the psi numbers but up front max should be 2.2 and rear if fully laden 2.7 if not fully laden 2.2....got front and rear back to range...tried my no hands tactic but in dark even with interior lights on couldn't make out
If there was as much shaking...or if this could be related in anyway to tire pressure? So gonna give it a shot tomorrow

[andrewwynn]

I don't ever recall having a shimmy that could be seen not felt. If you can't feel it my first thought it was in the road.

I've never experienced an off balance wheel that couldn't be felt. Both my X5s need the rear control arms front axle replaced and the primary symptom is wheel shake when either slight braking at speed or just the right amount of crown in the road trying to force the wheel off the self centered caster.

To discount the control arms the tests are:

Medium to light braking from 60>50 or 50> 40 mph

Driving straight on a level road (least crown eg center lane of three) then drive in a gentle "S" in your lane. 1 foot back and forth is enough. Use just two fingers to steer. If the control rods are shot you should feel just 2-3 wiggles at moment the wheels flip from right to left over the self centered spot.

If you get a tiny wiggle reliably and especially if both tests are positive it's for sure the front axle rear control arms.

FCP euro has a great price on lamforder brand.

[stiubhartach]

Wheels will bounce if they're very far out of balance. The bounce is usually not speed dependent though.

For wheel bounce that's in a narrow speed range, such as very bad between 60 and 70 but smooths out at 80 is due to harmonics in the suspension components.

The first place to look is the lower thrust arm bushings (also called tension struts).

#6 in this diagram:


https://www.realoem.com/bmw/enUS/sho...diagId=31_0521

[andrewwynn]

I've had stupid sloppy tension struts aka front control arms and never caused any shake just bad thud when the wheels would push 3/4" backwards into the car when I hit the brakes firmly


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[Overboost]

I am by no means a specialist but why would wheels be balanced by spinning them if speed had no effect?

[andrewwynn]

They are spun to determine where the misbalance is. Spinning exaggerates the amount of offbalance.

An out of balance wheel will pull harder from the center with more and more force as the wheel turns faster.

This will mean more force proportional to speed squared so it will always be worse when faster however as pointed out above often the shake can be absorbed by the suspension until it finds a resonance in the suspension components. That is why sometimes the shake can be much worse say from 55-60 mph then perfectly ok until 75-80.

If you have a shake that is very reliable at specific speeds nearly 100% chance that is an out of balance or out of round wheel.

Do your "light grip" test at different speeds and see if there are specific speeds you get a shake and if it disappears above and below. If so, tire balance problem.

You can often eliminate with a front to back rotate of the tires. If shake went away it's the tires.


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