[Zengineer]

Ive been struggling with steering wheel vibrations for a while now. I think i can feel the same vibration at all speeds, slightly amplified during light braking sometimes. Wheels and tires been road force balanced multiple times.

Last night i swapped tension struts and the vibes are now more pronounced. Any ideas what vibrations a stiffer tension strut would make worse?

I just now rotated tires front to back and nothing changed.

Wheel bearings?
Wishbones?
Bad alignment shop?
Any suggestions whats next?

I really want to like this car, but...... its giving me bad vibrations.... sorry i couldnt resist that one.

Thanks everyone!

[HP Autosport]

Originally Posted by Zengineer

Ive been struggling with steering wheel vibrations for a while now. I think i can feel the same vibration at all speeds, slightly amplified during light braking sometimes. Wheels and tires been road force balanced multiple times.

Last night i swapped tension struts and the vibes are now more pronounced. Any ideas what vibrations a stiffer tension strut would make worse?

I just now rotated tires front to back and nothing changed.

Wheel bearings?
Wishbones?
Bad alignment shop?
Any suggestions whats next?

I really want to like this car, but...... its giving me bad vibrations.... sorry i couldnt resist that one.

Thanks everyone!

Do you have hub centric wheels or running spacers?

[Zengineer]

Hub centric. Rial salernos.

[BillionPa]

Are you using plastic hub rings?

[Zengineer]

No hub rings, rims are hub centric, rial salernos.

[mike-y]

brakes? warped rotors maybe?

Never heard of those tires....

[Route 16]

tie rod?

[abhishriv]

Probably warped rotors. Especially since you mention it's more pronounced when applying brakes.

[Zengineer]

Thats sad to hear since the rotors are new.... will have to get that checked out also.

Thanks for the replies everyone!

[IGoFast1589]

It could very well be your tires. You have another set of wheels/tires you can throw on to find out? Sometimes if they wear unevenly the tread blocks can cause a nasty vibration and audibly loud sound, like mud tires on the street sound.

[cleex024]

Originally Posted by IGoFast1589

It could very well be your tires. You have another set of wheels/tires you can throw on to find out? Sometimes if they wear unevenly the tread blocks can cause a nasty vibration and audibly loud sound, like mud tires on the street sound.

Yes I would have to agree since you put new stiffer rods on anything wrong would only amplify the problem. I would guess the tires too

[twright]

I have had sticking front brake calipers cause vibrations. You can tell if one is sticking because the wheel will be warmer than the other front one.

[Zengineer]

Ok ill look closer into the brakes, but i did just get all four corners road force balanced, so i assume they would detect a tire defect?

Weird that brakes only pulse through the steering wheel up to like 20% braking force and never any feedback through the pedal.

Also today on a 4 hour road trip i noticed something unique: the steering wheel vibrates visibly about 1\16th of an inch in either direction for approx 20 seconds, then it vibrates at a much lower, non-visible amplitude for approx 20 seconds. This cycle repeated constantly regardless of gear, rpm, road slope, and persisted from about 65 to 85+ mph. Has anyone ever heard of this constant cycle of varying vibration amplitude?

Because it varies, i tend to think it is not tire related.... maybe power steering system... any ideas?

[jjellyneck]

I like a rock solid car with no vibrations, so your puzzle has me intrigued. The power steering might have some credence. Hmmm. I keep thinking of some kind of rotational mass that is slightly out of round or out of balance. As many mentioned...hubs, bearing that is faulty or does not fit perfectly. I will ask a few friends as well.

[Zengineer]

Thank you very much!

Maybe we can go at it the other way to. If the vibration amplitude varies, can we rule anything out? Tires? Brakes?

Is it possible that I somehow buggered up my tension strut replacement DIY?

Thanks!

Edit: After searching around some more, tie rod ends appear to be the next most likely culprit. Followed by a steering rack issue. I've had multiple shops look at the suspension for excessive play though, and none of those shops found any issues...

I've had issues with bad DWS tires in the past. I had to go through 7 of them before I found a good set of 4 that wouldn't vibrate.

Since you're, presumably, running a square setup try rotating the tires front to back and see if the vibration gets any better/worse if you end up noticing it changing from the front to the rear, etc. If it does, then that of course will narrow down your possible causes for the problem.

You said you had the tires road forced balanced but what were the results? The machine won't kick back a "bad tire" result unless it's 19lbs of road force or more. I've found that these tires WILL vibrate at anything more than 9lbs of road force. Took me forever to figure that out, but that might very well be your problem.

[Zengineer]

Originally Posted by FCobra94

I've had issues with bad DWS tires in the past. I had to go through 7 of them before I found a good set of 4 that wouldn't vibrate.

Since you're, presumably, running a square setup try rotating the tires front to back and see if the vibration gets any better/worse if you end up noticing it changing from the front to the rear, etc. If it does, then that of course will narrow down your possible causes for the problem.

You said you had the tires road forced balanced but what were the results? The machine won't kick back a "bad tire" result unless it's 19lbs of road force or more. I've found that these tires WILL vibrate at anything more than 9lbs of road force. Took me forever to figure that out, but that might very well be your problem.

Hmmm interesting. The results were about 13 lbs of road force on at least two of the tires. One was like 26, so they 'match balanced' it, and reduced it down to around 13 lbs.

Would excessive road force cause constant levels of vibration? I am a little bit doubtful of the tires just since my vibration intensity varies. The intensity even varies on long straight stretches of smooth highway. (I thought that maybe it was wheels and tires, and somehow they were 'phasing' in and out of sync which caused intensity variation, but I think I ruled that out).

Thank you very much for the feedback!

Originally Posted by Zengineer

Would excessive road force cause constant levels of vibration?

Yes. That's the whole point. If there is excessive road force, you're basically rolling around on a wheel/tire assembly that is shaped like an egg instead of a perfect circle. Now, this isn't perceptible to the human eye obviously as we're talking about thousands of an inch at this point (see articles listed below) but a couple thousands of an inch in variation is all it takes before you start feeling vibration.

Originally Posted by Zengineer

I am a little bit doubtful of the tires just since my vibration intensity varies. The intensity even varies on long straight stretches of smooth highway. (I thought that maybe it was wheels and tires, and somehow they were 'phasing' in and out of sync which caused intensity variation, but I think I ruled that out).

Yup. I had the same issues. For instance, one tire which had a road force of 17lbs would "hop" from 30-45 mph and then vibrate slightly at higher speeds. One tire with 11lbs of road force would vibrate the steering wheel at speeds of 50 mph+ and was rhythmic in nature, but didn't exhibit any issues below highway speeds. It's all a result of the variance in harmonics between the wheel/tire assembly, suspension, and chassis, etc. Never have I had such an issue with cars other than this BMW, but I guess these cars are just more sensitive to road force when compared to other makes/models (research on the topic points to Miatas, G8s, and some Cadillacs being equally, if not more, sensitive to road force as well). My testing for all this was marking down the road force for each wheel/tire and driving on a brand new freshly paved highway back to back to note any differences. With each iteration, the vibration type (hopping, rhythmic, varying intensity, etc.) would change depending on the road force and was ONLY felt in the wheel/tire that had more than 9 lbs of road force.

In *my* experience, all I can say is that the difference between 11 lbs and 8 lbs of road force will result in a tire that vibrates and one that doesn't. Now that everything on my car is below 9 lbs (4, 4, 8, 7) I can tell you that I am no longer experiencing vibration. The guys at the tire shop, speed shop, specialty store, etc. (I've been to 4 trying to get this issue straightened out) will think you're crazy, but that's because they don't know any better. The only thing that fixed the issue for me was swapping tires/force matching until those numbers got to where they are now. No other variables. No other changes. Period.

Here's some more info on the subject:
http://www.gsp9700.com/technical/5098t/5098t.htm

http://www.gsp9700.com/technical/4202T/5THEO003.htm

http://www.gsp9700.com/technical/4514T.htm (this one shows how traveling at a higher speed actually reduces vibration due to the harmonics spoken about in the previous article)

[Zengineer]

Originally Posted by FCobra94

Yes. That's the whole point. If there is excessive road force, you're basically rolling around on a wheel/tire assembly that is shaped like an egg instead of a perfect circle. Now, this isn't perceptible to the human eye obviously as we're talking about thousands of an inch at this point (see articles listed below) but a couple thousands of an inch in variation is all it takes before you start feeling vibration.


Yup. I had the same issues. For instance, one tire which had a road force of 17lbs would "hop" from 30-45 mph and then vibrate slightly at higher speeds. One tire with 11lbs of road force would vibrate the steering wheel at speeds of 50 mph+ and was rhythmic in nature, but didn't exhibit any issues below highway speeds. It's all a result of the variance in harmonics between the wheel/tire assembly, suspension, and chassis, etc. Never have I had such an issue with cars other than this BMW, but I guess these cars are just more sensitive to road force when compared to other makes/models (research on the topic points to Miatas, G8s, and some Cadillacs being equally, if not more, sensitive to road force as well). My testing for all this was marking down the road force for each wheel/tire and driving on a brand new freshly paved highway back to back to note any differences. With each iteration, the vibration type (hopping, rhythmic, varying intensity, etc.) would change depending on the road force and was ONLY felt in the wheel/tire that had more than 9 lbs of road force.

In *my* experience, all I can say is that the difference between 11 lbs and 8 lbs of road force will result in a tire that vibrates and one that doesn't. Now that everything on my car is below 9 lbs (4, 4, 8, 7) I can tell you that I am no longer experiencing vibration. The guys at the tire shop, speed shop, specialty store, etc. (I've been to 4 trying to get this issue straightened out) will think you're crazy, but that's because they don't know any better. The only thing that fixed the issue for me was swapping tires/force matching until those numbers got to where they are now. No other variables. No other changes. Period.

Here's some more info on the subject:
http://www.gsp9700.com/technical/5098t/5098t.htm

http://www.gsp9700.com/technical/4202T/5THEO003.htm

http://www.gsp9700.com/technical/4514T.htm (this one shows how traveling at a higher speed actually reduces vibration due to the harmonics spoken about in the previous article)

Wow that is extremely educational and helpful. Thank you very much!

When I am driving down a smooth highway, with the cruise control set to 80 (for example, also occurs at other constant velocities), the steering wheel vibrates visibly for about 20 seconds, then the vibrations subside so that the steering wheel vibrations are not visible, for about 20 seconds, then that cycle continues to repeat for the entire trip.

Did you come across those symptoms in your experiences?

They 'cyclical' nature of my vibration intensity doesn't seem like an EXACT match for the balance issues you've described.

That being said, every time I have had my tires road force balanced, they change something. Which tells me that I haven't yet found a fully competent balancer. I will probably keep chasing that based on your experience, thanks again very much for the feedback!

I've had similar symptoms during my countless iterations of: balance, install, rebalance, exchange tire, repeat at shop #2, etc.

If I could associate the sensation to a sound it would go: wubb wubB wuBB wUBB WUBB WUBB WUBb WUbb Wubb wubb .... car feels smooth .... wubb wubB wuBB wUBB WUBB WUBB WUBb WUbb Wubb wubb .... car feels smooth .... etc., much like you've experienced. This too was at a constant speed on a smooth, newly paved highway. The ONLY tire that would be making that vibration/sensation though was the tire that did not come at/under 9 lbs of road force. All the others were fine except for the the one(s) that read over that figure.

Again, the cyclical' nature of vibration intensity you're describing all has to do with the balancing harmonics of the wheel/tire assembly. If the tire or wheel lacks uniformity, that will be evident in one of the first couple harmonics (whether it be the first, second, third, etc.):
http://en.wikipedia.org/wiki/Tire_uniformity

If everything else is checking out ok (suspension, braking components, tie rod ends, etc.) then it all comes back to where the rubber meets the road...Use this tool to help you find a competent road force balance operator:
http://www.gsp9700.com/search/findgsp9700.cfm

I ended up finding a wheel refinishing shop that knew exactly what was going on and understood how to use the machine to it's fullest potential.

What also helped to get a better balance was that they used a lug centric adapter to mount the wheel to the balancing machine:
http://www.haweka-usa.com/PDFs/PassC...uct%20info.pdf

Instead of just shoving the hub portion of the wheel onto a cone, this adapter helps to better center the wheel onto the balancing machine in order to get a more accurate reading. It may seem trivial, but in my experience, every little bit helps...

[Zengineer]

Originally Posted by FCobra94

I've had similar symptoms during my countless iterations of: balance, install, rebalance, exchange tire, repeat at shop #2, etc.

If I could associate the sensation to a sound it would go: wubb wubB wuBB wUBB WUBB WUBB WUBb WUbb Wubb wubb .... car feels smooth .... wubb wubB wuBB wUBB WUBB WUBB WUBb WUbb Wubb wubb .... car feels smooth .... etc., much like you've experienced. This too was at a constant speed on a smooth, newly paved highway. The ONLY tire that would be making that vibration/sensation though was the tire that did not come at/under 9 lbs of road force. All the others were fine except for the the one(s) that read over that figure.

Again, the cyclical' nature of vibration intensity you're describing all has to do with the balancing harmonics of the wheel/tire assembly. If the tire or wheel lacks uniformity, that will be evident in one of the first couple harmonics (whether it be the first, second, third, etc.):
http://en.wikipedia.org/wiki/Tire_uniformity

If everything else is checking out ok (suspension, braking components, tie rod ends, etc.) then it all comes back to where the rubber meets the road...Use this tool to help you find a competent road force balance operator:
http://www.gsp9700.com/search/findgsp9700.cfm

I ended up finding a wheel refinishing shop that knew exactly what was going on and understood how to use the machine to it's fullest potential.

What also helped to get a better balance was that they used a lug centric adapter to mount the wheel to the balancing machine:
http://www.haweka-usa.com/PDFs/PassC...uct%20info.pdf

Instead of just shoving the hub portion of the wheel onto a cone, this adapter helps to better center the wheel onto the balancing machine in order to get a more accurate reading. It may seem trivial, but in my experience, every little bit helps...

Fascinating! I definitely had a strong case of the wubb WUBB wubbs. Do you think a good shop can get road force down from 13 to 9? I suppose it depends on the tire...

I REALLY appreciate all of your detailed feedback.