This car is driving me insane!

[stoopid]

Bad news, vibrations are slowly returning. I notice them especially when the road surface is super new and smooth. There is a very clear vibration (fast oscillation) that cat be felt in the whole car and increases with speed. It starts as low as 65mph.
There is also a significant increase in this vibration when I apply the brakes. If I quickly lift my foot off the brake pedal the vibration stays the same in type but diminishes a lot in intensity. So I don't believe it's caused by the rotors (which are fairly new).
I also don't believe it's the tires or wheel imbalance. It's not fast enough somehow.. don't know how to explain. Plus I've been switching tires like socks, as you know if you've read the topic.
My only idea is now that it's caused by something suspension related. Either ball joints or bushings or something there.
So, a riddle:
What causes a vibration on very smooth roads but not on slightly worn roads
and
Why does vibration increases under load (linear with speed increase) and when brake pressure is applied
but sometimes it does not vibrate at all.

Have you had your tires road force balanced? I had a car that this was needed and would create a slight shake at and above a certain speed. Road force balancing immediately resolved the problem.

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What is Road Force Balance? Eliminate Tire Vibrations

A road force balance test (road force balancing) detects non-balance and weight related problems associated with tire uniformity by simulating road force.

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Any minor imperfection with a single tire can create vibrations (bulges, blown belt, out of round, bent rim, alignment, etc).

 

[7Andrei7]

Yes tired than and I even got 4 new tires to replace the other 4 new tires I had
The ride was fine for about 3000 km with the latest new tires. Then it slowly started to develop this shake.
Only thing I did not change was the rims.
I will put on the summer set in a few weeks but I doubt that will change something.

How long do bushings last? My car has 63k miles.
As the shake/vibration is not always there I’m thinking something is triggering it.

 

[Ohiocruiser]

@Ohiocruiser how can those be diagnosed?

Usually when they start going south, they start making humming noice, that will go louder and louder over time. Check for 12-6 play.

 

[Ohiocruiser]

Yes tired than and I even got 4 new tires to replace the other 4 new tires I had
The ride was fine for about 3000 km with the latest new tires. Then it slowly started to develop this shake.
Only thing I did not change was the rims.
I will put on the summer set in a few weeks but I doubt that will change something.

How long do bushings last? My car has 63k miles.
As the shake/vibration is not always there I’m thinking something is triggering it.

It is still too early for lower arm bushings to go bad. But it can't hurt to check. Especially the rear one. (Big round one)

 

[Ozstung]

I'd put money on alignment and wheel balance. My car is out of alignment 2 days after i get one. Just waiting on the caster kit to arrive.

 

[D.J.]

I'd put money on alignment and wheel balance. My car is out of alignment 2 days after i get one. Just waiting on the caster kit to arrive.

Did you crash?
Or hit a massive pot hole?

How can an alignment be "out" 2 days after it was aligned?

Someone forget to tighten some jam nuts?

 

[7Andrei7]

I have the first TUV check (technical inspection) on Tuesday and will be done at a different Kia dealership. I'm hoping they'll do a proper check of the suspension and brakes. Maybe they'll find something.
Every now and then I can hear a very short metalic squeal, like a spring compressing. Sounds like it comes from the left front. It only occurs when the car has been parked for a few days and I either go over the first speed bump or I make some parking manoeuvres to get out of the underground garage.
But it's one quick sound and that's it. I can't reproduce it if I push on the car or move it side to side. I checked the front springs visually and can't see anything loose. Don't know if that is anything... I assumed it's just something settling in the suspension after a long pause.

PS: Is there a way to get my flag to stop changing under my user-name? It always changes based on the provider of my internet. So from my place I'm on a german flag. I my office I get an austrian flag and on my mobile I have a romanian flag

 

[Ozstung]

Did you crash?
Or hit a massive pot hole?

How can an alignment be "out" 2 days after it was aligned?

Someone forget to tighten some jam nuts?

Neither of those two as far as im aware. I had three alignments in 6 weeks none will stick. Car has a permanent pull to the left ( opposite with Lh drive)which i found is not as uncommon as i thought plenty of people looking to use this caster kit. I'll let you all know if it works if it ever arrives. (Ordered on a FB special buy in Oz)

 

[byebyeSTI]

did you try installing the sub frame bushing kit ? worked wonders on mine after like 4 alignments that went bad after a few days .

 

[GT Elite]

Neither of those two as far as im aware. I had three alignments in 6 weeks none will stick. Car has a permanent pull to the left ( opposite with Lh drive)which i found is not as uncommon as i thought plenty of people looking to use this caster kit. I'll let you all know if it works if it ever arrives. (Ordered on a FB special buy in Oz)

The pull maybe due to road crown causing the car to drift to the left. This effect can be minimized with caster lead on the left front wheel (more caster on the left front than the right front). Note, however, that when you are in the right lane the car could noticeably drift/pull to the right More than expected.

 

[rpoffen]

Sounds a lot like the forum thread on the GMC Sierra about highway speed vibrations experienced on 2014-2019 GMC light duty trucks. Last I checked there were about 1000+ pages of comments. Most complaining about the same thing, massive vibrations starting at 65-70MPH on up to over 80MPH.
GM repurchased untold number of trucks because they couldn't solve the issue.
At first, they always blamed the tires, round after round of tire replacements, road force balancing, etc. For most, nothing helped, hence the buy-backs.
Some had torque converters replaced. Transmission fluids flushed and filled, drive shafts replaced, axles replaced, shocks replaced. Some users took it upon themselves to demonstrate how the driveshaft flexed excessively, or how the axle flange was not on center, even having custom driveshafts made.
I stopped paying attention a couple years ago, don't know if they ever found a single solution.

 

[7Andrei7]

I mean, mine did have entire months of no vibrations. But every single time I change something like switching to different season wheels or putting on new tires the problem returns. Then it would usually be fixed within 4-5 rebalancing attempts.
This week I had the 3-year technical inspection and it passed with flying colours. No problems with suspension. They found one wheel 25g out of balance. Not sure this will fix anything, didn't get the chance to test it.

 

[JTank1]

Something to try; sometimes steering wheel vibrations are due to too much toe in. May be within spec but try a neutral 0.0 deg toe and see if it goes away. Has happened to me before where the tire "skips" at certain speeds.

 

[D.J.]

I mean, mine did have entire months of no vibrations. But every single time I change something like switching to different season wheels or putting on new tires the problem returns. Then it would usually be fixed within 4-5 rebalancing attempts.
This week I had the 3-year technical inspection and it passed with flying colours. No problems with suspension. They found one wheel 25g out of balance. Not sure this will fix anything, didn't get the chance to test it.

Sounds like you confirmed it is a balancing issue.

If it can be fixed by balancing, it is most certainly a balancing issue.

Something to try; sometimes steering wheel vibrations are due to too much toe in. May be within spec but try a neutral 0.0 deg toe and see if it goes away. Has happened to me before where the tire "skips" at certain speeds.

OP already confirmed it gets fixed by balancing.
No amount of alignment is going to resolve and out of balance issue.


Are people stealing your wheel weights at night while you sleep?

 

[7Andrei7]

I can now confirm that the 25g issue was the thing causing the vibrations in normal driving conditions. Drove today for a couple of hours at 80+ mph and it was all smooth. Probably lost some weights at the carwash? Don't know.

But, I can also confirm that there is still some vibration under braking (upwards of 65mph). So there are probably some rotor issues as well. I'll have them checked next week. Still under warranty. EBC rotors at the front and Textar rear. EBC yellow stuff pads all around.

 

[D.J.]

I can now confirm that the 25g issue was the thing causing the vibrations in normal driving conditions. Drove today for a couple of hours at 80+ mph and it was all smooth. Probably lost some weights at the carwash? Don't know.

But, I can also confirm that there is still some vibration under braking (upwards of 65mph). So there are probably some rotor issues as well. I'll have them checked next week. Still under warranty. EBC rotors at the front and Textar rear. EBC yellow stuff pads all around.

This was a really long thread for an unbalanced wheel and pulsating brakes

 

[RogueIV]

I'd just rebed the brakes before wasting time going back to the shop. Takes all of 5 mins to do and might fix your issue.

 

[D.J.]

I'd just rebed the brakes before wasting time going back to the shop. Takes all of 5 mins to do and might fix your issue.

It took several months to confirm if was a simple wheel balance issue...

Do you really think 5 minutes will resolve anything here?

 

[7Andrei7]

It took several months to confirm if was a simple wheel balance issue...

Do you really think 5 minutes will resolve anything here?

If only someone like you would've told me (and all mechanics) it was just a simple wheel balance issue we could've saved all this time and money with 10+ balancing attempts (with or without road force), a couple of alignment checks and a full set of 4 Michelin tires replaced on warranty.
If we had more people like you all mechanical trouble would simply not exist. Everything would just be a simple ________ issue that any idiot could instantly fix.

 

[7Andrei7]

I'd just rebed the brakes before wasting time going back to the shop. Takes all of 5 mins to do and might fix your issue.

I did try to re-bed them at some point but did not really help.
However, this was during the time when the car was vibrating at all times, not just under braking. It was very complicated to isolate and fix each of the sources. I was fairly sure the brakes were not to blame at all, until yesterday.
PS: Just checked and front rotors + pads are 10.000 km old. Could my wheel problems and constant vibration for about 60% of that distance have caused the rotors to deform?