Steering Wheel Shimmy, Slight vibration Options

[Mowog4]

I have a slight vibration in my steering wheel, it is very minor but noticeable. It does not get worse with speed, but I find it annoying. Every suspension piece on the front end of the car has been replaced, new struts, new wheel bearings, etc.. I thought, possibly it was a problem with flat spotting of tires, but new tires and wheels did not make a difference I see online there is a steering stabilizer, that is the only thing I haven’t changed down. Can anyone tell me what that does?
Thanks
Ed

[emerygt350]

Have you had the wheel balance checked?

[Mowog4]

Have you had the wheel balance checked?

I have rebalanced the wheels and rotated them

[bkrantz]

You can try on-car wheel balancing.

[mgp4591]

How's your alignment?
You've heard this before, right??

[Mowog4]

How's your alignment?
You've heard this before, right??

I have had the alignment done by a race shop, then redone when I got the modified elephant racing modified struts and bump steer kit. It is baffling.

[Shivers]

Do you have hub centric rings up front. Sometimes non hub centric wheels / hubs can become unbalanced or be installed unbalanced.

[Jamie]

Do you have hub centric rings up front. Sometimes non hub centric wheels / hubs can become unbalanced or be installed unbalanced.

I had a similar "unbalanced" feeling wheel with new tires, and the problem was a non-hubcentric 12mm spacer in L front. Careful remounting alignment with lug tightening sequence resolved the problem. (IMG:style_emoticons/default/aktion035.gif)

[Superhawk996]

Need more info:

What speed range does it occur?

Is it at all dependent on road surface?

4 lug or 5 lug?

You say suspension was rebuilt, what bushings were used?

What spring rates and torsion bars?

Is the shake in the steering wheel trying to rotate (oscillate) the steering wheel. Or is it just a consistent up/down vibration without a sense of rotating the steering wheel in your hand?

[Mowog4]

See below:quote name='Superhawk996' date='Aug 15 2025, 07:50 AM' post='3219443']
Need more info:

What speed range does it occur? 30 to 120

Is it at all dependent on road surface? Mostly freeway or good back roads

4 lug or 5 lug? 5 lug, 70’s 911 suspension, Bilstein struts raised spindles, struts are revalved on all 4 corners, coil overs on all four wheels, 930 tie rods, new OEM wheel bearings, factory bushings,

You say suspension was rebuilt, what bushings were used? Factory rubber.

What spring rates and torsion bars?200lb springs, coil overs replaced torsion bars (although it did it before the coil over swap

Is the shake in the steering wheel trying to rotate (oscillate) the steering wheel. Or is it just a consistent up/down vibration without a sense of rotating the steering wheel in your hand? Just a vibration, steering wheel does not feel like it is rotating.
[/quote]

[930cabman]

are the wheel bearings adjusted correctly

[Superhawk996]

You’re not going to like my answer.

Without driving your car or putting some instrumentation on the car to measure what is occurring, this is an opinion from a guy that spent his career doing chassis engineering.

The spring rates you’re using are very high and are going to drive a lot of road input into the chassis. This is just a fact when spring rates increase. Those spring rates are well over double the OEM spring rates.

914’s don’t have much road isolation to start with. It is a good sign that you used factory rubber bushings. Symptoms you describe would only be worse with urethane, Delrin, or god forbid heim joints.

The turbo tie roads are a very direct connection into the steering rack with zero NVH isolation. This is going to drive road input and vibration right into the steering wheel. The steering is very precise with Turbo tie roads but degraded NVH isolation the tradeoff.

I say this largely based on the fact that you’re saying the steering wheel isn’t oscillating and that it occurs across all speeds from 30mph on up.

There are two things you could try but they probably won’t help:

1) On car wheel balancing. Shops that can do this are getting hard to find. The advantage of on-car balance is that it can compensate for small imbalances like 911 brake rotors that may not be perfectly hub centric.

2) Road force balance of the wheel and tire assembly. Hunter road force balancers can compensate for tire harmonics and spring rate differences within the tire carcass. Based on your descriptions this is a long shot because tire radial 1st harmonic issues usually present at 50-60 mph, and tire radial 2nd harmonic usually vibrates more at 25-35 mph. Based on your description of vibration not varying with speed, this probably isn’t going to help. It may slightly - but I don’t think it would solve your complaint.

If you are comparing the vibration level and refinement of your 914 to a modern road car, you are going to be disappointed.

The other suggestions here about making sure the rear lug centric wheels are mounted properly are valid but again given how the chassis is set up with high spring rates, I don’t suspect that is what you’re complaining about.

If you want to get a real deal root cause, I’d find a shop that is capable of putting an accelerometer on the steering wheel and order tracking it to road speed and Engine RPM. Usually this would be done with a tool like the Vetronix MTS 4000 or similar instrumentation.

[Mowog4]

Thanks for the input, I’ll find a road force balancer and give that a shot. Other than that I will live with it.

You’re not going to like my answer.

Without driving your car or putting some instrumentation on the car to measure what is occurring, this is an opinion from a guy that spent his career doing chassis engineering.

The spring rates you’re using are very high and are going to drive a lot of road input into the chassis. This is just a fact when spring rates increase. Those spring rates are well over double the OEM spring rates.

914’s don’t have much road isolation to start with. It is a good sign that you used factory rubber bushings. Symptoms you describe would only be worse with urethane, Delrin, or god forbid heim joints.

The turbo tie roads are a very direct connection into the steering rack with zero NVH isolation. This is going to drive road input and vibration right into the steering wheel. The steering is very precise with Turbo tie roads but degraded NVH isolation the tradeoff.

I say this largely based on the fact that you’re saying the steering wheel isn’t oscillating and that it occurs across all speeds from 30mph on up.

There are two things you could try but they probably won’t help:

1) On car wheel balancing. Shops that can do this are getting hard to find. The advantage of on-car balance is that it can compensate for small imbalances like 911 brake rotors that may not be perfectly hub centric.

2) Road force balance of the wheel and tire assembly. Hunter road force balancers can compensate for tire harmonics and spring rate differences within the tire carcass. Based on your descriptions this is a long shot because tire radial 1st harmonic issues usually present at 50-60 mph, and tire radial 2nd harmonic usually vibrates more at 25-35 mph. Based on your description of vibration not varying with speed, this probably isn’t going to help. It may slightly - but I don’t think it would solve your complaint.

If you are comparing the vibration level and refinement of your 914 to a modern road car, you are going to be disappointed.

The other suggestions here about making sure the rear centric wheels are mounted properly are valid but again given how the chassis is set up with high spring rates, I don’t suspect that is what you’re complaining about.

If you want to get a real deal root cause, I’d find a shop that is capable of putting an accelerometer on the steering wheel and order tracking it to road speed and Engine RPM. Usually this would be done with a tool like the Vetronix MTS 4000 or similar instrumentation.

[Superhawk996]

I’m getting old. Here’s a new solution that popped up as I was digging for info. Seems the old school Vetronix and Pico vibration analyzers are getting hard to come by. But . . . I stumbled on this.

No where near accurate (or expensive) as Vetronix and Pico but at a price point of $100 could be pretty interesting. I have no affiliation and have never used this app though I’m very tempted to give it a try.


https://www.youtube.com/watch?v=zAQ2AM5Y5sA?si=1afG1SuJjl6wL7ww


Interesting though as tech progresses to make use of the accelerometer built into our smart phones. (IMG:style_emoticons/default/idea.gif)

[Mowog4]

I’m getting old. Here’s a new solution that popped up as I was digging for info. Seems the old school Vetronix and Pico vibration analyzers are getting hard to come by. But . . . I stumbled on this.

No where near accurate (or expensive) as Vetronix and Pico but at a price point of $100 could be pretty interesting. I have no affiliation and have never used this app though I’m very tempted to give it a try.


https://www.youtube.com/watch?v=zAQ2AM5Y5sA?si=1afG1SuJjl6wL7ww


Interesting though as tech progresses to make use of the accelerometer built into our smart phones. (IMG:style_emoticons/default/idea.gif)

That’s interesting, we will play around with it

[rjames]

It took me going to 3 different shops to find one that could correctly balance the wheels.

[Maury4]

I have a slight vibration in my steering wheel, it is very minor but noticeable. It does not get worse with speed, but I find it annoying. Every suspension piece on the front end of the car has been replaced, new struts, new wheel bearings, etc.. I thought, possibly it was a problem with flat spotting of tires, but new tires and wheels did not make a difference I see online there is a steering stabilizer, that is the only thing I haven’t changed down. Can anyone tell me what that does?
Thanks
Ed

Just throwing this out; but did you check the steering wheel disc that connects it to the rack? It's under the fuel tank.

Rick

[914sgofast2]

Might be a long shot, buy are you certain that you don't have one or more bent wheels? All the tire balancing methods in the world can't compensate for a bent wheel.

[Front yard mechanic]

Bent wheel or 2 my guess

[Mowog4]

Might be a long shot, buy are you certain that you don't have one or more bent wheels? All the tire balancing methods in the world can't compensate for a bent wheel.

I have two sets of wheels that I have tried, both of them run tru, and neither are bent.