So this year I decided I did not want the excessive road noise associated with aggressive tread patterns on winter and AT tyres so... I got to thinking what if I put noise deadining recording studio foam inside the tyre?

Well, with clearly too much time on my hands, and a Db meter to hand I decided to find out.

Firstly, the control test:

•275 40 22 continental cross contacts
- at 40mph = 71db
- at 50mph = 72db
- at 60mph = 74db
- at 70 and 80 = 74db

• 275 60 20 cooper discoverer winter
- at 40mph = 75db
- at 50mph = 76db
- at 60mph = 76db
- at 70 and 80 = 78db

• 275 60 20 cooper discoverer winter + my foam

- at 40mph = 71db
- at 50mph = 72db
- at 60mph = 74db
- at 70 and 80 =75db

Results were very interesting, needless to say I am running my cooper tyres with foam.

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Charles, firstly. yes you do have too much time on your hands Secondly and seriously, is there a noticeable difference in noise when the decibel drop is less than 3% ?? Thanks

Certainly is yes because Db noise levels are not based on percentage, they are staged. For example a drop in 5db would result in a noticable noise reduction equivalent to 2/3rds the original level.

On the decibel scale, the smallest audible sound (near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB

Meaning that the tyre noise on the coopers prior to foam would have (in reality) felt like it was 50% more noisy on the road

It's a little bit like the weather forecast saying it's 1c outside but it feels like -6c

I do not profess to know the exact science behind it here is a little taster of how it works
https://science.howstuffworks.com/questi

Continental 'contisilent' tyres use the same approach with foam so its tried & tested to be worthwhile I guess.

Bloody Brilliant !! Every day is a school day, thanks for that, some good info to banter around at the Christmas table (seriously), I love finding out new things

When using dB in RF power an increase of 3dB doubles the power -- a decrease will halve it -- it's a logarithmic scale.

So the 3dB difference in dB/spl at 70mph will be significant! Current: 2011 FFRR Vogue SE 4.4 TDV8
Previous: -
2004 FFRR Vogue 4.4 V8 with LPG
1997 P38 4.0 SE with LPG
1997 P38 4.6 Vogue with LPG

Thankyou for your dedication to the RR cause - lol.

That's quite a noise reduction !

Any other evaluations planned that we can look forward to?  Paul,
2001 Discovery 2 TD5, 211,000 miles & climbing
2006 FFRR TDV8 Vogue 145,000 miles & climbing
Member of Midland (Land) Rover Owners Club, www.mroc.co.uk

Did your control set of Conti's have foam in or not ?

As above, Conti do 2 tyres in the same size, one has foam, the other doesn't

No they were not the conti silents. No foam just normal tyres.

I have it on good authority from a Land Rover platform employee that LR are experimenting with sound deadening inserts to tyres to reduce the problem of tyre noise. If I am not mistaken you can buy the inserts, unfortunately I don't know where from.

I have had a series of punctures with my lawn mower.....something to do with blackthorn and wild rose....

When I was a kid I had an insert on my push bike to avoid punctures... is there anything for the lawnmower tyres?
Iseki 22

Bill
 Filters are in fact so good that in certain circumstances, when the ambient air is already polluted, a diesel car will tend to extract more particles from the air than it emits. Emissions Analytics worked with........etc etc

He who dies with the most toys wins...

Yes... Rhino gel...

That is a great idea!! Hated my coopers for the noice...and tbh for the cracks in the sidewalls after 10 k miles.

Have you experienced any issues with balancing the tire? I remember someone tried a similar experiment on a tesla forum and had constant issues with balancing and vibrations.

I recently had a tour of a Tesla facility. All of the tyres on the racks were foam lined, so there is definitely something in this. Previously..
Vogue SE TD6
Defender 90 2.4
Defender 110 TD5
Vogue 3.5 EFI