Suspension Performance and How to Improve it!

[PMB]

I feel like not enough people are talking about the wheels and tires and how they affect the composure of the car.

I was swapping my summers on this weekend, and if I'd had a scale with me, I would have weighed them out so we could have precise numbers to compare.I can tell you that the stock 19" wheels and tires are back breaking HEAVY, compared to my winter setup. I'm in a 2019 GT Limited (Canada, therefore AWD). I had the winters on almost from the moment I picked up the car in November 2018

Winter 225/45R18 Blizzak X-Ice on Enkei Drako 18x8. (Square setup). Wheels are supposed to be 21.6lb/ea
Summer stock 19" Michelin PS4's on the 'B-type' (5x'Y'-spoke). (Stagger Setup) Supposedly, 35lb front, and 33lb rear.

I had to do a long commute as soon as the summer tires were on, and I could tell a HUGE different between the two setups, especially for vibration and harshness coming from the rear end. I've put about 5,000km on my winter tires. All winter I felt the car was very planted, and I had nothing to complain about with the rear end, maybe a couple odd mid corner bumps gave me some pause, but nothing to the level I'd been reading about on the forums or seeing in video reviews.

Well, after a single 200km drive, I know why people have misgivings about the comportment of the Stinger's rear. Every pot hole, and ripple in the road made the rear of the car shimmy and wiggle. I feel that it's due to the low profile of the 19" tires, and the massive weight of the stock wheels, and tires. Again, in my opinion, it's just too much unsprung mass for the springs and dampers to control, with the added fact that the low profile rears will tend to transfer additional energy wheels.

 

[Not Here Anymore]

I feel like not enough people are talking about the wheels and tires and how they affect the composure of the car.

I was swapping my summers on this weekend, and if I'd had a scale with me, I would have weighed them out so we could have precise numbers to compare.I can tell you that the stock 19" wheels and tires are back breaking HEAVY, compared to my winter setup. I'm in a 2019 GT Limited (Canada, therefore AWD). I had the winters on almost from the moment I picked up the car in November 2018

Winter 225/45R18 Blizzak X-Ice on Enkei Drako 18x8. (Square setup). Wheels are supposed to be 21.6lb/ea
Summer stock 19" Michelin PS4's on the 'B-type' (5x'Y'-spoke). (Stagger Setup) Supposedly, 35lb front, and 33lb rear.

I had to do a long commute as soon as the summer tires were on, and I could tell a HUGE different between the two setups, especially for vibration and harshness coming from the rear end. I've put about 5,000km on my winter tires. All winter I felt the car was very planted, and I had nothing to complain about with the rear end, maybe a couple odd mid corner bumps gave me some pause, but nothing to the level I'd been reading about on the forums or seeing in video reviews.

Well, after a single 200km drive, I know why people have misgivings about the comportment of the Stinger's rear. Every pot hole, and ripple in the road made the rear of the car shimmy and wiggle. I feel that it's due to the low profile of the 19" tires, and the massive weight of the stock wheels, and tires. Again, in my opinion, it's just too much unsprung mass for the springs and dampers to control, with the added fact that the low profile rears will tend to transfer additional energy wheels.

Personally for my Awd Stinger here in Kelwona BC I was just so glad take my winters off as my winter tire with studs were of course loud , and after reading the form message s on here about the rear being a bit loose after going ruff patches . I put on Eibach springs and rear sway bar , this seemed to stabilize the back end better

 

[MerlintheMad]

feel like not enough people are talking about the wheels and tires and how they affect the composure of the car.

OEM Wheel Weight!
That is one of several threads talking about wheels and there are others talking about tires and sway bars.

Personally, I've found the Eibach rear sway enough of an improvement on a car that already handled well. The "floaty/playful" rear end was not a factor in actual handling; i.e. did not threaten to "unstick" the AWD. I can't speak for RWD. But from what I read, it's just a different sort of handling to get accustomed to, not better or worse.

Summer tires are definitely going to transmit road noise and ride harder than A/S or winter tires. But if you only want a comfy ride at the expense of performance, I think that the Stinger is not the best car for you. A G80 or G90 would suit better for sheer comfort. But they are not going to hang with the Stinger on a twisty mountain highway, or be as much fun to drive over all; and certainly they will not compete in the compromise of utility/practicality and startlingly good looks. They are boring, comfy rides, judging solely by their outer skins.

 

[Never thought]

I feel like not enough people are talking about the wheels and tires and how they affect the composure of the car.

I was swapping my summers on this weekend, and if I'd had a scale with me, I would have weighed them out so we could have precise numbers to compare.I can tell you that the stock 19" wheels and tires are back breaking HEAVY, compared to my winter setup. I'm in a 2019 GT Limited (Canada, therefore AWD). I had the winters on almost from the moment I picked up the car in November 2018

Winter 225/45R18 Blizzak X-Ice on Enkei Drako 18x8. (Square setup). Wheels are supposed to be 21.6lb/ea
Summer stock 19" Michelin PS4's on the 'B-type' (5x'Y'-spoke). (Stagger Setup) Supposedly, 35lb front, and 33lb rear.

I had to do a long commute as soon as the summer tires were on, and I could tell a HUGE different between the two setups, especially for vibration and harshness coming from the rear end. I've put about 5,000km on my winter tires. All winter I felt the car was very planted, and I had nothing to complain about with the rear end, maybe a couple odd mid corner bumps gave me some pause, but nothing to the level I'd been reading about on the forums or seeing in video reviews.

Well, after a single 200km drive, I know why people have misgivings about the comportment of the Stinger's rear. Every pot hole, and ripple in the road made the rear of the car shimmy and wiggle. I feel that it's due to the low profile of the 19" tires, and the massive weight of the stock wheels, and tires. Again, in my opinion, it's just too much unsprung mass for the springs and dampers to control, with the added fact that the low profile rears will tend to transfer additional energy wheels.

I don’t think the unsprung weight has anything to do with the shimmy. I dropped 10 lbs a wheel after adding rotary forged wheels and there was no impact on the shimmy. I put in Eibach springs which reduced the shimmy, and greatly improved handling and the ride is much less harsh over road imperfections. I then added the ATQ collar kit and the shimmy is 95% gone.

 

[Marc Collins]

I don’t think the unsprung weight has anything to do with the shimmy. I dropped 10 lbs a wheel after adding rotary forged wheels and there was no impact on the shimmy. I put in Eibach springs which reduced the shimmy, and greatly improved handling and the ride is much less harsh over road imperfections. I then added the ATQ collar kit and the shimmy is 95% gone.

Do you have a link to collar kit? Sorry, I missed it if already posted.

 

[jondyer]

Kia Stinger - ATQ Subframe Chassis Collar Kit

 

[Marc Collins]

Kia Stinger - ATQ Subframe Chassis Collar Kit

Thanks! Very interesting.

 

[RLittle]

I use the Bridgestone AS 18” tires on my AWD for winter and just replaced them with General Gmax RS in 245/40-19 on Rohana rotary formed wheels and the change stiffened up the suspension feel considerably!

Used to drive in sport, now drive in comfort.

 

[turboAWD]

I don’t think the unsprung weight has anything to do with the shimmy. I dropped 10 lbs a wheel after adding rotary forged wheels and there was no impact on the shimmy. I put in Eibach springs which reduced the shimmy, and greatly improved handling and the ride is much less harsh over road imperfections. I then added the ATQ collar kit and the shimmy is 95% gone.

So the ATQ collar kit is recommended? How much work is the installation?

 

[Zotto]

For the Collar install.

 

[Never thought]

So the ATQ collar kit is recommended? How much work is the installation?

It’s up to you as to whether you think the $200 is worth it. There isn’t a drastic improvement in the ride and handling but there is an improvement. And it does help get rid of the shimmy. The video is a little over the top.

 

[xot1]

I have some interesting news.

I cant remember the thread but someone said that it would be nice if we could change the suspension settings to be firmer.
I just read on a Korean site that some people got the service center to change the stock suspension settings for them. I will investigate more but if true that is worth trying.

There are 7 settings.
Russia, North America, Europe, China, Korea, Australia and default.

Not a lot of information is available so I don't know which setting is the best but compared to Korea, Australia is more smooth, America and Europe are more firm (but different type of setting).

 

[Marc Collins]

I have some interesting news.

I cant remember the thread but someone said that it would be nice if we could change the suspension settings to be firmer.
I just read on a Korean site that some people got the service center to change the stock suspension settings for them. I will investigate more but if true that is worth trying.

There are 7 settings.
Russia, North America, Europe, China, Korea, Australia and default.

Not a lot of information is available so I don't know which setting is the best but compared to Korea, Australia is more smooth, America and Europe are more firm (but different type of setting).

View attachment 23208

And while they were at it, they could have easily provided three settings per jurisdiction, or a simple menu to select a master/global setting that affects the two existing built-in settings. Why not give everyone the choice of any setting? What marketing moron thought it was a good idea to restrict this by region, as if everyone in a region thinks alike or has the same preferences, instead of allowing user choice when there is clearly a simple way to choose from many settings?

 

[xot1]

And while they were at it, they could have easily provided three settings per jurisdiction, or a simple menu to select a master/global setting that affects the two existing built-in settings. Why not give everyone the choice of any setting? What marketing moron thought it was a good idea to restrict this by region, as if everyone in a region thinks alike or has the same preferences, instead of allowing user choice when there is clearly a simple way to choose from many settings?

Why not look at the bright side of things?

 

[brancky3]

I have some interesting news.

I cant remember the thread but someone said that it would be nice if we could change the suspension settings to be firmer.
I just read on a Korean site that some people got the service center to change the stock suspension settings for them. I will investigate more but if true that is worth trying.

There are 7 settings.
Russia, North America, Europe, China, Korea, Australia and default.

Not a lot of information is available so I don't know which setting is the best but compared to Korea, Australia is more smooth, America and Europe are more firm (but different type of setting).

View attachment 23208

Cool info, thanks! Do you know if any region has a 'Sport +' setting? I want my sport setting to be FIRM

 

[Marc Collins]

Why not look at the bright side of things?

Which is what? You think KIA is suddenly going to reverse direction 180 degrees?

 

[Waynerm002]

It’s good to know this can be done! I think the aftermarket folks are going to figure out the code and offer us some tuning options in the future. I’m liking how mine feels now but after driving the G70 I wand that on my Stinger, well their comfort mode set to my Sport.

 

[Rev_Night]

It’s up to you as to whether you think the $200 is worth it. There isn’t a drastic improvement in the ride and handling but there is an improvement. And it does help get rid of the shimmy. The video is a little over the top.

$200 for some bolts? really?

 

[Ruturaj]

$200 for some bolts? really?

My thoughts exactly. I don't get simple parts (non moving like CV axle) like sway bar, bolts, frame support bars are crazy expensive. And the guy in video went to shop to install it and may be paid 100 more.

 

[Rev_Night]

SHOW ME THE DYNO