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Rim size and tyre noise

Posted: Thu Aug 08, 2019 11:03 pm
by nichop
Hi. I’ve recently moved from a Landrover Discovery 3 which we’ve owned for 9 years, to a Kodiaq Edition 2.0TSI. There is tons I like about the car but the one area where I’m disappointed is road noise and specifically low frequency noise, particularly when going over bumps and marks in the road. I don’t remember the Kodiaq I test drive being this bad but , it was a test drive. I’m not expecting it to be as good as the Discovery which wafted over roads on its air suspension but, our Kodiaq really does seem particularly bad. Now it has 19” rims and I wonder whether this is causing the noise to be far worse compared to 18 and 17”.
Does anyone have experience of both 19” and smaller rims? Noticeably different road noise on the smaller rims?

Re: Rim size and tyre noise

Posted: Thu Aug 08, 2019 11:53 pm
by Silverbear
My understanding is that smaller wheels are in general more comfortable. I don't have much experience with 19 inch wheels but have 18 inch Summer wheels and 17 inch Winter wheels on my Kodiaq. The 17 inch steel wheels are noticably better than the 18 inch alloy wheels. The rubber is different though which further complicates it. The 17 inch wheels have Michelin CrossClimates fitted, the 18 inch are Pirelli something-or-other tyres. If my 17 inch steel wheels were alloy wheels I'd keep them on the car all year. That said the car is so quiet either wheels are good enough for me. The first thing I'd check is your tyre pressure in case they are too high.

Re: Rim size and tyre noise

Posted: Fri Aug 09, 2019 7:59 am
by Kenny R
As above I would check the tyre pressures. I have 19” wheels with Pirelli Scorpion tyres and run them at 35psi and can’t say road noise is a problem. I also have 17” winter wheels and whilst they make the ride and handling a bit softer I can’t say there is any increase/ decrease in noise.
Although I haven’t read of it happening on a Kodiaq it has been reported on many other models that the transport blocks were left in on top of the dampers. Might be worth lifting up the rubber cover and having a look.

Re: Rim size and tyre noise

Posted: Fri Aug 09, 2019 9:43 am
by FoxtrotAlpha
I presently have 19" Triglav rims on mine and I would say that the road noise it pretty much as I expected, it's not whisper quite but nor is in intrusive, I am running the standard fit SUV - Ventus S1 Evo2's. When I test drove a Kodiaq with 20" Vega rims I didn’t find it was significantly different to the 19's (although reviews would suggest the 20's make more noise than 19's).

I believe consensus is that bigger you go in rim size more noise you make as larger tyres tend to have more surface area on the road due to tyre width and they tend to have smaller profile depth. From what I can see the 18", 19" and 20" tyres have the same width (235mm) as each other and the 17" have a reduced width of 215mm that may account for the 17s being less noisy. That said maybe the noise differences is due to the 17", 18", 19" and 20" tyres having different profile depths which are 65mm, 55mm, 50mm and 45mm respectively.

Re: Rim size and tyre noise

Posted: Fri Aug 09, 2019 9:50 am
by Silverbear
FoxtrotAlpha wrote:
Fri Aug 09, 2019 9:43 am
I presently have 19" Triglav rims on mine and I would say that the road noise it pretty much as I expected, it's not whisper quite but nor is in intrusive, I am running the standard fit SUV - Ventus S1 Evo2's. When I test drove a Kodiaq with 20" Vega rims I didn’t find it was significantly different to the 19's (although reviews would suggest the 20's make more noise than 19's).

I believe consensus is that bigger you go in rim size more noise you make as larger tyres tend to have more surface area on the road due to tyre width and they tend to have smaller profile depth. From what I can see the 18", 19" and 20" tyres have the same width (235mm) as each other and the 17" have a reduced width of 215mm that may account for the 17s being less noisy. That said maybe the noise differences is due to the 17", 18", 19" and 20" tyres having different profile depths which are 65mm, 55mm, 50mm and 45mm respectively.
The tyre 'depths' are fractions of tyre width, not mm. Thus the 18 inch wheels have 235/55R18 tyres which means 0.55 x 235mm = 129.25mm of rubber depth.

I think it will be a functon of rubber depth and pressure which more or less is an aspect of a cars suspension.

Re: Rim size and tyre noise

Posted: Fri Aug 09, 2019 9:55 am
by Kenny R
FoxtrotAlpha wrote:
Fri Aug 09, 2019 9:43 am
That said maybe the noise differences is due to the 17", 18", 19" and 20" tyres having different profile depths which are 65mm, 55mm, 50mm and 45mm respectively.
That’s not how tyre profiles work. The 65, 50 etc is a percentage of the tyre width, not mm’s directly.
Picture shows difference in sidewall height between 18” wheel (130mm) and 19” wheel (117mm)

7694D8E4-71AA-457D-B32A-96AABA3C9743.jpeg


Re: Rim size and tyre noise

Posted: Sat Aug 10, 2019 9:38 pm
by nichop
thanks for all the replies. Lower profile tyres and their lesser sidewalls can increase noise, as can the specific tyres used. I was interested to know whether anyone has experience with different profiled tyres (and rim sizes) on their same car and so were able to give me a back to back comparison or observation. Sounds like there are a few and the consensus is, not a lot of difference between them.
I'll definitely check out the suspension blocks so thanks for that suggestion!

Nick

Re: Rim size and tyre noise

Posted: Tue Aug 13, 2019 7:03 am
by nichop
Chatting to a different dealer who was far more helpful, he suggested that the 5 seater (which we have) may be noisier than the 7 seater because there is effectively less sound deadening between the road and the cabin. Also we tested the 7 seater before buying and it was definitely quieter so it would make sense. I guess I’ll have to look for ways to add additional sound deadening to the boot floor.

Re: Rim size and tyre noise

Posted: Tue Aug 13, 2019 8:26 am
by Silverbear
nichop wrote:
Tue Aug 13, 2019 7:03 am
Chatting to a different dealer who was far more helpful, he suggested that the 5 seater (which we have) may be noisier than the 7 seater because there is effectively less sound deadening between the road and the cabin. Also we tested the 7 seater before buying and it was definitely quieter so it would make sense. I guess I’ll have to look for ways to add additional sound deadening to the boot floor.
My 5 seater is by far the quietest car I have owned. It has the larger spare wheel and the associated polystyrene under the boot floor so if the dealer is suggesting a 5 seater has the potential to be a kettle drum without this I suppose there might be some viable physics in that. Do you have the larger spare wheel in your 5 seater? For me the point of the 5 seater is the better spare wheel and better towing abilities unless of course one needs 6/7 seats.

If you have the larger spare wheel I would look elsewhere for the cause. That said mine is a 4x4 and has a towbar too, all of which will change the natural frequency of the rear end but I have considerable experience with a 5 seater FWD with full size spare, without tow bar, and it was just as quiet. Did you check the tyre pressures?

Re: Rim size and tyre noise

Posted: Tue Aug 13, 2019 9:41 am
by old man
I'm assuming the car is a new one ?
I'm surprised nobody has mentioned tyre makes and different treads yet. Whilst I don't imagine Skoda would fit any make of tyre to their new cars that would be particularly noisy, the tyres on your car could be a different make to the ones on the demonstrator, which could make a difference.
You don't state where you live. If for instance you lived near me, I'd be happy to take you out in my car to see if it's any better than yours.
Maybe there's another owner near you that could do that.