My takeaways from this:

• Dissapointed that Kia put these silly tyres on the car. Apparently the foam makes virtually no difference to sound levels.
• Dissapointed that my UK Kia garage didn’t suggest that as a problem when I called them, and that the French Kia garage didn’t spot it (they had EV6s on their lot, so they can’t be inexperienced with it). 2-3 years after EV6 launch this must have happened to a number of owners.
• What kind of rubbish is Kumho making, that after only 15k miles, and in hot BUT not scorching weather, the foam causes this problem?

I hope I’ve helped any of you who get this issue in the future.

Also, would love to hear your thoughts on this…

I've had foam lined tyres for years, and never heard of this problem before. Driven in scorching weather, over 40C. Noise reduction isn't huge, but I'd rather have quieter.

Is it possible you just got a bad one? If an uncommon problem, the garages might not notice at first.

 

Agree am on my third car with foam in the tyres so probably 60,000 km some long motorway trips in very hot weather. This case could be an unfortunate manufacturing defect in the Tyre. All my brands are different, Goodyear then Michelin and now Pirelli…..
Edited to add thanks for the post it is helpful to know if this experience should I suffer a similar issue😉

 

@InspectorGadget What a frustrating experience for you. That is disappointing that the Kia dealers don't seem to know these cars very well.

This my 4th EV in 4 years with acoustic foam inside the tyres (Continental and Pirelli). I've never had foam come loose, and I've driven when it's bloody hot too.

Personally, from my experience, I think acoustic foam in EV tyres makes a very noticeable difference in suppressing tyre roar on an EV, especially when you have big fat tyres.

 

@InspectorGadget What a frustrating experience for you. That is disappointing that the Kia dealers don't seem to know these cars very well.

This my 4th EV in 4 years with acoustic foam inside the tyres (Continental and Pirelli). I've never had foam come loose, and I've driven when it's bloody hot too.

Personally, from my experience, I think acoustic foam in EV tyres makes a very noticeable difference in suppressing tyre roar on an EV, especially when you have big fat tyres.

I have had experience in changing foam lined tyres to All Season tyres with no foam on 2 occasions & noticed no difference on noise levels.

 

The only issue I have heard about with foam tyres is that many tyre depots refuse to repair punctures because of that foam. There is no real reason for this except that it can take longer as the foam has to be removed from the site of the puncture so that the repair can adhere to the rubber. Only a small amount needs to be cut away and doesn't need replacing. It only slightly affects balancing afterwards. It is suspected that the tooth-sucking tyre guy frowning at the foam just wants to sell you a new tyre. Don't fall for it if the tyre is otherwise in good condition with many miles left on it.

 

Hopefully I did just get a unusually bad tyre, fingers crossed this doesn’t happen to me or anyone else again.

Although I just Googled “tyre foam causing vibrations” and there’s lots of threads from Tesla and other EV owners who have had the same issue. So seems like I want the first and won’t be the last.

Thankfully I can still use the same tyre, even without the foamat least according to my tyre shop who seem to know their stuff.

 

Pistonheads has quite comments on tyre foam failing and that it doesn't reduce noise significantly. For an extra dB, I'll do without.

 

I have never had this issue previously, but this is a very interesting post. Recently, after it was 35C for a few days, I have noticed that my car has a vibration at highway speeds. I thought it was simply because my car now has 83,000km and my tires are fairly worn, but now that you mention the foam, I know my 20" GT-Line tires have some and I think it may have become loose in one of more of the wheels. This will make for an interesting short video as I am sure others are experiencing the issue. I have to investigate my tires to see if this really is the issue. Thanks for sharing.

 

And if anyone is wondering what the foam in a tyre looks like - I took a picture of a new one before fitting.

 

That is very interesting and surprising. In the Tesla and Niro EV tires, the foam is a complete band around the entire inside of the tire. I don't understand why they would insert little blocks that offer little sound deadening as opposed to a full strip, which actually makes a difference. Thanks for the picture.

 

Different tyre manufacturers have different approaches, Pirelli use blocks from what I can see from their publicity about what they call PCNS.
They are all looking to stop the reverberations inside the tyre as it hits the road you can hear the ring with a wheel and tyre off the car.
Ev’s have made this technology even more interesting but it was brought in before the ups became common on luxury cars, my e class had tyres with it.
I have never had any issues with detachment of the lining but clearly it is something that can happen but is not enough for me as yet not to replace my tyres with those without.

 

Kumho tyres seem to have a continuous foam strip. On Nexen tyres there are gaps in the foam.

 

To clarify, there was one strip of foam in the Nexen tyre - it`s ends just didn`t meet up, hence the one gap.

 

Surely tyre noise comes from the tyre contact with the road. How does a piece of foam inside the tyre make any difference?

 

A lot of the contact noise is transmitted via the tyre itself, so absorbing noise inside the tyre (which is really just converting it to heat) reduces the noise level transmitted into the car itself. I suspect there is also some acoustic effect from the hollow chamber that is the inside of the tyre that may normally resonate a bit and make some frequencies more prominent (think of banging a drum, versus banging a solid lump of wood). Drummers often tone down drums, the one in the band I played in around 50 years ago used to stuff a blanket inside the bottom of his bass drum, the old school equivalent to tyre foam, perhaps.

 

I’ve had the same foam problem with my Polestar.. twice! The first time the dealer wanted £500 for a new wheel hub. Apparently a wheel was warped! And this is not a warranty issue. Long story short. Took the car to a wheel specialist who told me the hubs were perfect. Back to the dealer and lo and behold I get it back fixed and told it was a simple balancing. Back again a few months later and told it’s the foam. If this goes again they are taking this crap out!

 

I just want to spend a moment to give my respect to the name of the tyre. Kumho

 

Bjorn Nyland mentioned this in one of his recent videos, specifically about the ev6....might be a Kumho problem.

 

No spare tyre when you get a flat tyre, just a can of tyre foam that ruins your tyre unrepairable.

 

I had a similar issue last winter and it turned out the problem got worse after switching to cheap tyres without knowing they had internal foam. For better results and reliability, I went with https://pneusquebec.net/pneus-225-70r19-5/ and the difference was night and day—no more strange noises or shaking above 60 km/h. Might be worth checking your tyre specs and making sure you're not dealing with badly fitted foam.

 

What foam are we talking about here... I am confused (happens a lot!)

 

A thin layer of foam that is glued against the inside of the tread, supposedly to make the tyre quieter.

 

Had it come loose in one of my Nexen tyres, the factory-fit on my Gen2 Kona

 

Kumho tyres on my EV6 have it as well. I think every major brand has done tyres with foam liner nowadays