FAQ: Vibration under braking: warped rotors? NO!

[MerlintheMad]

Found this thread as I was searching for an answer to my brake issues with my 2018 Genesis G80 Sport, which is VERY similar to the Stinger GT in almost all regards. So this problem is with the G80 Sport too.

Welcome, non Stinger "cousin".

 

[Kamauxx]

Found this thread as I was searching for an answer to my brake issues with my 2018 Genesis G80 Sport, which is VERY similar to the Stinger GT in almost all regards. So this problem is with the G80 Sport too.

My Genesis dealer got Genesis to replace the rotors at 15K miles the first time it happened as “an exception”. However, it appeared with the new rotors at 20K miles (just 6K miles later). I have been “babying” the breaks in the meantime, knowing they wouldn’t cover them again and while I look around for an aftermarket upgrade.

This thread was extremely helpful!! Thanks for this. I will try the re-bedding technique (once I can find a road where I can do all those runs without ever actually stopping), but it sounds like better pads are the key.

Would drilled/slotted/vented rotors also help? If I already have to replace the rotors, may as well get the best ones I can.

I did mine in the hwy late at night. The Girodisc Magic pads call for hwy speed bedding/cooling. Not sure what brand Hyundai/Kia uses or what the recommended procedure is.

Here's Girodisc's recommendation, for reference:

· Drive the vehicle to a remote area and perform at least 20 brake applications of 3-second duration. Use light deceleration with varying starting speeds. Stoplight traffic can work well for this.
· After the repeated stops, drive the vehicle for several miles (on highway generally) with little or no braking in order to adequately cool the components.
· While on highway, safely perform 10 more braking applications using light to medium pressure for periods of about 5 seconds, with at least one minute between applications for cooling.
· After the above process is completed, the system is ready for normal use.

 

[MerlintheMad]

I did mine in the hwy late at night. The Girodisc Magic pads call for hwy speed bedding/cooling. Not sure what brand Hyundai/Kia uses or what the recommended procedure is.

Here's Girodisc's recommendation, for reference:

· Drive the vehicle to a remote area and perform at least 20 brake applications of 3-second duration. Use light deceleration with varying starting speeds. Stoplight traffic can work well for this.
· After the repeated stops, drive the vehicle for several miles (on highway generally) with little or no braking in order to adequately cool the components.
· While on highway, safely perform 10 more braking applications using light to medium pressure for periods of about 5 seconds, with at least one minute between applications for cooling.
· After the above process is completed, the system is ready for normal use.

No "hard" braking? Fascinating. I got the impression from earlier reading about bedding pads that you were supposed to do highway speeds, which someone said were sixty to seventy mph; then push the brakes firmly to bring speed down to under thirty mph; and do this a dozen or so times.

The addition of "one minute between applications for cooling" is something new. Would that be a dedicated Girodisc instruction or would that be good methodology for all brake pad bedding?

 

[eflyguy]

I did the upgraded pads in my Sorento in a parking lot. There's no one best way for every pad, you just need to follow recommendation for the pads you happen to buy.

 

[BabblingBafoon]

Find a big parking lot (think community college on a Saturday early am). You can easily do the bedding cycles and coast in between circling without stopping.

Good idea! I think I know where I could do this now. Thanks for the suggestion!!

 

[BabblingBafoon]

Welcome, non Stinger "cousin".

Thank you sir! Gotta love the 3.3T! Now just need to sort these brakes. LOL

 

[BabblingBafoon]

Welcome, non Stinger "cousin".

BTW, I am *considering* trading my G80 for the Stinger GT2... hard decision. My G80 Sport is definitely more luxurious and refined than the Stinger, but I also like the look of the Stinger and the functionality of the hatch. Also looking at the G70, which is more like my G80... just smaller. However, the Stinger seems to have WAY more support in the industry for aftermarket mods, and there is just enough difference between all of these vehicles to make it so you can't use ALL of the mods made for Stinger.

 

[jondyer]

Sidebar -

BTW, I am *considering* trading my G80 for the Stinger GT2... hard decision. My G80 Sport is definitely more luxurious and refined than the Stinger, but I also like the look of the Stinger and the functionality of the hatch. Also looking at the G70, which is more like my G80... just smaller. However, the Stinger seems to have WAY more support in the industry for aftermarket mods, and there is just enough difference between all of these vehicles to make it so you can't use ALL of the mods made for Stinger.

I got rid of my V8 Genesis for the Stinger. I did have both for about 4 months to compare (and there was that whole repaint debacle).

I can say for sure that I thought I would miss the Genesis more. To be honest, the only time I think of that car is when I pass one on the highway.

While the Stinger is not as luxurious, it does have all the tech and is infinitely more fun to drive, get better mileage and is much more functional. I considered a G70, but the back seat is way too small. In my opinion, the G70 does not look as good.

- Now back to the thread....

 

[max2382]

So I had this problem too. Car (GT2 rwd) is about 9 months old/11500 and for a few weeks I had problems with the brakes (vibrations, pulsing..etc) so I went to kia and they did not replace the rotors but they resurfaced them. All for free under warranty. The problem now is gone, but as soon I got the car I can definitely feel the brakes are "different". I would say they require to push harder and deeper to achieve the same brake power as before the resurfacing. Is this normal? The guy told me my rotors were warped. According to the article in this post thats impossible, but couldn't argue too much with him. He said it was my fault cause the way I drive. But I am not racing or hard drive at all. Just commuting 80 miles every day, sometimes with traffic, sometimes not bad. This never happened to me before, with any car I had, and they didn't have Brembos. So I am wondering how top notch brakes get rotors problems so quick when compared to crappy normal brakes of a common cheap car. I understand the pad etc...but I never had a car with "quality stuff" before and again, they never presented this issue.

 

[Helo58]

The way the rotors are turned is what requires the greater pedal force. The spiral grooves machined into the rotor are lifting the pad off of the rotor as the rotors spin. This is well known in motorsports but not as commonly known in the consumer circles. The proper way to grind performance brake rotors is with a Blanchard (or centerless) grinding process that doesn't leave a spiral path on the rotor surface. This is how new rotors are received. New rotors should be the preference if the option is given. Removing metal from the brake rotor should not be considered a true fix because the removal of the metal reduces the ability of the brakes to absorb and then dissipate heat generated during the braking process.

The rotors you have are not warped, they have deposits of the pad materials from due to a poor choice of pad materials by Kia. This is what causes the vibration problem. It progressively gets worse and will cause irreparable damage to your rotors if allowed to continue. You should look into aftermarket brake pads immediately or risk having the same problem occur again and outside of warranty.

 

[BabblingBafoon]

So I had this problem too. Car (GT2 rwd) is about 9 months old/11500 and for a few weeks I had problems with the brakes (vibrations, pulsing..etc) so I went to kia and they did not replace the rotors but they resurfaced them. All for free under warranty. The problem now is gone, but as soon I got the car I can definitely feel the brakes are "different". I would say they require to push harder and deeper to achieve the same brake power as before the resurfacing. Is this normal? The guy told me my rotors were warped. According to the article in this post thats impossible, but couldn't argue too much with him. He said it was my fault cause the way I drive. But I am not racing or hard drive at all. Just commuting 80 miles every day, sometimes with traffic, sometimes not bad. This never happened to me before, with any car I had, and they didn't have Brembos. So I am wondering how top notch brakes get rotors problems so quick when compared to crappy normal brakes of a common cheap car. I understand the pad etc...but I never had a car with "quality stuff" before and again, they never presented this issue.

The problem is the pads, not the rotors. The pads are too soft and are leaving deposits on the rotors that are giving them high spots, and therefore out of round and unbalanced (not warped).

If you read all the way through the thread (a lot of good info in here) you will see it doesn’t have to be driving the vehicle hard. Dragging the breaks when they heat up and then having to stop with the brakes on seems to be the biggest culprit for leaving the pad deposits.

We need new brake pads that are harder surface to mitigate this.

 

[MerlintheMad]

The problem is the pads, not the rotors. The pads are too soft and are leaving deposits on the rotors that are giving them high spots, and therefore out of round and unbalanced (not warped).

If you read all the way through the thread (a lot of good info in here) you will see it doesn’t have to be driving the vehicle hard. Dragging the breaks when they heat up and then having to stop with the brakes on seems to be the biggest culprit for leaving the pad deposits.

We need new brake pads that are harder surface to mitigate this.

I see people on their brakes the entire time coming down the canyons. They don't know how to brake properly. I can SMELL their brakes quite often. HOT! Much? The proper way to brake is press and release. You press and increase pressure then let go; repeat as needed. Try for more time off the brakes than on. My brakes are "like new" (at c. 14K miles, and I doubt that an additional 2K+ has changed anything). I am not saying the OE pads are great or even good. They are adequate if you use your brakes correctly.

I suppose that it is possible that the pads Kia opted for OE have a quality control issue: i.e. most of them are okay, but a small percentage are crap. If they were universally crap, of course there would have been an ISB long before now and we'd all be driving around on European spec pads.

 

[BabblingBafoon]

I see people on their brakes the entire time coming down the canyons. They don't know how to brake properly. I can SMELL their brakes quite often. HOT! Much? The proper way to brake is press and release. You press and increase pressure then let go; repeat as needed. Try for more time off the brakes than on. My brakes are "like new" (at c. 14K miles, and I doubt that an additional 2K+ has changed anything). I am not saying the OE pads are great or even good. They are adequate if you use your brakes correctly.

I suppose that it is possible that the pads Kia opted for OE have a quality control issue: i.e. most of them are okay, but a small percentage are crap. If they were universally crap, of course there would have been an ISB long before now and we'd all be driving around on European spec pads.

I don’t doubt that driving responsibly and using your brakes as you describe can help mitigate this issue, but these cars have quite a lot of performance and are very fun to drive very fast and hard, and the brakes get very hot when you are hard on them. The pads seem to be too soft for that type of driving, and couple that with doing this on “the street” and you often have scenarios where you have to arrest a LOT of speed very quickly and then be at a standstill, with those hot pads applied as they start to cool down and leave those deposits.

I guess what I am saying is, for the performance of the vehicle, they probably should have chosen harder compound pads. But it’s a trade off on noise/dust… i.e., the softer brakes are less noisy and dusty.

Would at least be nice an option to have harder pads.

 

[MerlintheMad]

Would at least be nice an option to have harder pads.

We're getting closer to that, from what I've been reading on here. I'm surprised it's taking this long. But export from Europe should be viable. While the aftermarket rotors already available over here should come with compatible pad upgrades.

Do the MY19 Stingers have the same OE pads? Are these "warped rotor" assertions following the MY19s?

 

[eflyguy]

I see people on their brakes the entire time coming down the canyons. They don't know how to brake properly. I can SMELL their brakes quite often.

Whether or not owners are not braking "correctly" isn't the issue. It's:

... with those hot pads applied as they start to cool down and leave those deposits.

Stated many times - it's holding the vehicle stationary with hot brake components that causes the pad material to be deposited. Essentially the "glue" that holds the pad material together will melt and attach to the rotors in those spots.

The solution is to simply be aware of how hard the brakes are being used, and avoid holding the vehicle stationary. This is not intuitive to most drivers - nor should it be!

Your average vehicle owner - and many mechanics - have no clue as to the real issue. The unfortunate choice of pads for US Stingers has exposed a lot of people to a problem that they've not had to deal with before.

 

[BabblingBafoon]

... The unfortunate choice of pads for US Stingers has exposed a lot of people to a problem that they've not had to deal with before.

And this is an overarching Hyundai / Kia issue, as I am experiencing the same behavior on my Genesis G80 Sport, which shares many of the same components as the Stinger (same with the G70).

 

[MerlintheMad]

Whether or not owners are not braking "correctly" isn't the issue.

Hot brakes is the issue. And I was explaining how to avoid overheating your brakes.

Granted, better pads would make hot brakes a non issue.

 

[MisterMac]

I think there is a lot of rubbish in this thread.

I've driven 10,000+ miles on my new Kia Factory Rotors with the same OEM pads that came on my GT2.

There is zero, I repeat, zero, as in absolutely NO vibration.

As the only thing that changed are the rotors which Kia replaced under warranty, the evidence is clear. The initial rotors were faulty. There is nothing wrong with the pads . There is nothing wrong with the new rotors Kia is using.

Whether the new rotors are made of a different material which isn't prone to build up of pad material, or the original rotors were Warped as the master tech said, I don't know.

What I do know is this, there is absolutely no valid reason to spend money on after market pads or rotors to accommodate normal diving conditions.

 

[Helo58]

I think there is a lot of rubbish in this thread.

I've driven 10,000+ miles on my new Kia Factory Rotors with the same OEM pads that came on my GT2.

There is zero, I repeat, zero, as in absolutely NO vibration.

As the only thing that changed are the rotors which Kia replaced under warranty, the evidence is clear. The initial rotors were faulty. There is nothing wrong with the pads . There is nothing wrong with the new rotors Kia is using.

Whether the new rotors are made of a different material which isn't prone to build up of pad material, or the original rotors were Warped as the master tech said, I don't know.

What I do know is this, there is absolutely no valid reason to spend money on after market pads or rotors to accommodate normal diving conditions.

Well, there you have it folks. The brake problem has been solved. Disregard all personal experiences, the opinions of two noted car magazines who had problems with the pads, and all who had their problems resolved by changing the pads. Good grief.

 

[MisterMac]

Well, there you have it folks. The brake problem has been solved. Disregard all personal experiences, the opinions of two noted car magazines who had problems with the pads, and all who had their problems resolved by changing the pads. Good grief.

Glad you finally caught on!