Polo Blue GT - sound proofing against tyre noise

Chat about your 6R/6C model Polos here!
Mike Austin
Getting There!
Posts: 52
Joined: Sat Mar 10, 2018 1:48 pm
Drives: Polo Blue GT
Location: Bristol

Polo Blue GT - sound proofing against tyre noise

Post by Mike Austin »

I have just bought a Polo Blue GT with 6,000 miles on the clock and Bridgestone Potenzas 215/40R17. Having moved from a silky smooth Skoda Fabia Mk1 2.0i, I find the road noise from the back a bit intrusive. There have been several posts on tyre noise here and it seems that tyre noise is to be expected.
When I test drove the car, I noticed the noise but thought it could be overcome. Having put the low shelf in the back with items (such as blankets, tools, etc) in between that and the spare wheel well, there was negligible improvement.
What are the most effective sound proofing options here - e.g. boot liners, wheel well liners, wheel arch liners etc? Indeed, can anything be done about this noise at all?
Ricmondo
Gold Member
Posts: 529
Joined: Sat Feb 21, 2015 2:03 am
Drives: Polo Blue GT
Location: Teddington

Re: Polo Blue GT - sound proofing against tyre noise

Post by Ricmondo »

My BGT came with Dunlop’s, I have not noticed undue tyre noise. Not the cheapest solution but perhaps you need to change tyre manufacturer.
SRGTD
Bling Bling Diamond Member
Posts: 3508
Joined: Sun Oct 11, 2015 9:40 pm
Drives: 2020 AW Polo GTI+, Pure White.
Location: UK

Re: Polo Blue GT - sound proofing against tyre noise

Post by SRGTD »

Bridgestone tyres do have a reputation for being quite noisy. They’re also hard wearing (some say, at the expense of grip, especially in colder weather). If your car has only covered 6,000 miles, I’d say it’ll be a while before your tyres wear out and need replacing, and the rears will outlast the fronts unless you rotate your wheels back to front so all 4 tyres need replacing at the same time.

Back onto your issue with tyre noise at the back of your car. I don’t have any personal experience of this product, but you could try lining the boot floor and spare wheel well with Dynamat. It’s not cheap, but it gets good reviews from those who have used it.

If you use the search facility on the forum (top right of screen) and search on Dynamat, you’ll see that some forum members have used it for noise suppression in various parts of their cars.
Mike Austin
Getting There!
Posts: 52
Joined: Sat Mar 10, 2018 1:48 pm
Drives: Polo Blue GT
Location: Bristol

Re: Polo Blue GT - sound proofing against tyre noise

Post by Mike Austin »

SRGTD wrote: Thu Mar 22, 2018 12:20 pm Bridgestone tyres do have a reputation for being quite noisy. They’re also hard wearing (some say, at the expense of grip, especially in colder weather).
Yes, one thing I noticed with this car is the low rolling resistance, perhaps partly explaining why I got 48mpg on my first 1/2 tank.
Back onto your issue with tyre noise at the back of your car. I don’t have any personal experience of this product, but you could try lining the boot floor and spare wheel well with Dynamat. It’s not cheap, but it gets good reviews from those who have used it.
Thanks. It seems that under the rear bench is often soundproofed. There are several options for Dynamat. An open question: what type of Dynamat do people use here?
Ricmondo
Gold Member
Posts: 529
Joined: Sat Feb 21, 2015 2:03 am
Drives: Polo Blue GT
Location: Teddington

Re: Polo Blue GT - sound proofing against tyre noise

Post by Ricmondo »

Dynamat is very good and not too difficult to work with.
Mike Austin
Getting There!
Posts: 52
Joined: Sat Mar 10, 2018 1:48 pm
Drives: Polo Blue GT
Location: Bristol

Re: Polo Blue GT - sound proofing against tyre noise

Post by Mike Austin »

I have not added any sound-proofing yet, but the noise is becoming quite intrusive. It appears to emanate from the back. It is quite noticeable at about 20mph, although it can just about be detected at 10mph. As these are quite low speeds, I checked my tyre pressures thinking they might be too high. The car has only done about 1,000 miles since purchased from the VW dealer, when it had 5,871 miles on the clock. The tyres are Bridgestone Potenzas 215/40R17.
According to the label inside the petrol flap, they should have the following pressures:
TyrePressureLabel.jpg
Regarding the "i" on the second line, the manual says "In some vehicles: comfort tyre pressure for partial load"
The measured tyre pressures were front: 36psi, rear: 27psi. I doubt if they will have lost much in 1,000 miles from what the VW dealer set them at. Is my car is one of these "some vehicles". In any case, the rears seem to have been under-inflated by any measure. I would have thought that would tend to reduce the tyre noise. What do people think?
SRGTD
Bling Bling Diamond Member
Posts: 3508
Joined: Sun Oct 11, 2015 9:40 pm
Drives: 2020 AW Polo GTI+, Pure White.
Location: UK

Re: Polo Blue GT - sound proofing against tyre noise

Post by SRGTD »

I’ve had low profile Bridgestone tyres before, and have always found them to be quite noisy. Most Bridgestone tyres in 215/40 R17 size have a noise rating of 72db. compared to Dunlop Sport Maxx, which have a noise rating of 68db and Goodyear GSD3 Eagle F1 Which have a noise rating of 66db.

I wouldn’t put too much reliance in the dealer having set the tyre pressures at the manufacturers recommended setting before you picked up your car. I’ve had tyres set at incorrect pressures by the dealer on previous VW’s I owned when my car’s been in for service!
Mike Austin
Getting There!
Posts: 52
Joined: Sat Mar 10, 2018 1:48 pm
Drives: Polo Blue GT
Location: Bristol

Re: Polo Blue GT - sound proofing against tyre noise

Post by Mike Austin »

So the Goodyear tyres are 1/4 the noise level of the Bridgestones? That is quite significant!
SRGTD
Bling Bling Diamond Member
Posts: 3508
Joined: Sun Oct 11, 2015 9:40 pm
Drives: 2020 AW Polo GTI+, Pure White.
Location: UK

Re: Polo Blue GT - sound proofing against tyre noise

Post by SRGTD »

Mike Austin wrote: Wed Apr 25, 2018 4:25 pm So the Goodyear tyres are 1/4 the noise level of the Bridgestones? That is quite significant!
The GSD3’s have a load index 83, and I think your tyres are load index 87. Goodyear Eagle F1 Asymmetric3 are made in 215/40R 17 size with an 87 load index. Compared to the Bridgestones (have assumed yours are S001’s and not RE050A), the Asymmetic 3’s are more fuel efficient, have better wet grip, and are quieter.

Goodyear Eagle F1 GSD3
215/40R17 83Y
EU Label Summary
Fuel Efficiency: F
Wet Grip: B
Noise: 66dB

Goodyear Eagle F1 Asymmetric3
215/40R 87Y
EU Label Summary
Fuel Efficiency: C
Wet Grip: A
Noise: 69dB

Bridgestone S001 Potenza
215/40R17 87Y
EU Label Summary
Fuel Efficiency: E
Wet Grip: B
Noise: 72dB
Mike Austin
Getting There!
Posts: 52
Joined: Sat Mar 10, 2018 1:48 pm
Drives: Polo Blue GT
Location: Bristol

Re: Polo Blue GT - sound proofing against tyre noise

Post by Mike Austin »

Mine are the Potenza RE050A.
SRGTD
Bling Bling Diamond Member
Posts: 3508
Joined: Sun Oct 11, 2015 9:40 pm
Drives: 2020 AW Polo GTI+, Pure White.
Location: UK

Re: Polo Blue GT - sound proofing against tyre noise

Post by SRGTD »

Mike Austin wrote: Wed Apr 25, 2018 6:03 pm Mine are the Potenza RE050A.
Seems to be three versions of the RE050A on the Camskill website, which is where I’ve taken the information from, and it’s not clear what the difference is between them. All are 87 load index and speed rating ‘V’

Bridgestone RE050A Potenza
215/40R17 87V
EU Label Summary
Fuel Efficiency: E / F / C
Wet Grip: C / C / A
Noise: 72dB / 72dB / 71db
Mike Austin
Getting There!
Posts: 52
Joined: Sat Mar 10, 2018 1:48 pm
Drives: Polo Blue GT
Location: Bristol

Re: Polo Blue GT - sound proofing against tyre noise

Post by Mike Austin »

Going back to my original question, should I use the higher pressures or the lower "some vehicles" pressures? The manual would appear to suggest that, if the label includes this, then it is an option:
Comfort tyre pressure
In some vehicles, the tyre pressure sticker may show details of a "comfort" tyre pressure ⇒ Fig.  206 . This should make driving extra comfortable. Fuel consumption may increase when driving with comfort tyre pressure.
SRGTD
Bling Bling Diamond Member
Posts: 3508
Joined: Sun Oct 11, 2015 9:40 pm
Drives: 2020 AW Polo GTI+, Pure White.
Location: UK

Re: Polo Blue GT - sound proofing against tyre noise

Post by SRGTD »

No harm in trying it. Checked my tyre pressure label and it doesn’t include ‘confort’ tyre pressures like yours does. It does suggest on your label that comfort pressures are only appropriate for partial loads, so if you regularly carry a full car of passengers and luggage, then you’d need to adjust your tyre pressures accordingly.

As your tyre pressures are currently below the suggested ‘comfort’ pressure settings, increasing them to 39 psi front / 36 psi rear may reduce tyre noise a little, although other factors such as worn tyres (not applicable in your case) and tread pattern can also contribute to tyre noise.

Don’t forget to reset your TPMS once you’ve adjusted your tyre pressures.
Mike Austin
Getting There!
Posts: 52
Joined: Sat Mar 10, 2018 1:48 pm
Drives: Polo Blue GT
Location: Bristol

Re: Polo Blue GT - sound proofing against tyre noise

Post by Mike Austin »

I pumped up the tyres to the 'non-comfort' level of Front:300/3.0/44 and Rear:280/2.8/41. Unsurprisingly, the car is a bit lively over bumps and is not so comfortable now! However, the tyre noise has not changed - neither for the better nor for the worse, and not in pitch either. I could first of all try swapping fronts and rears, expecting the driven tyres to be a little more worn and less prone to noise. But I am beginning to suspect wheel bearings, even though there is only 7,000 miles on the clock.
I think different cars make a different noise as wheel bearings wear. About 40 years ago, I changed my Mini wheel bearings. They gave off a screaming sound as the case-hardening had cracked and they were sliding rather than rotating. I have watched several Youtube videos, but have not found one that corresponds to my car so that I can compare the noise.
veteran
Silver Member
Posts: 410
Joined: Tue Sep 19, 2017 12:27 pm
Drives: TSI 90 Match Edition 1.2
Location: London, UK

Re: Polo Blue GT - sound proofing against tyre noise

Post by veteran »

I think I'm right in saying that the biggest impact on perceived road noise comes from the car's suspension, ie. from the combination of the resiliences of the coilsprings, the dampers, and the rubber bushings used in them and on the wishbones and on other stabilising droplinks. All of these represent the transmission paths of the noise generated at the tyre/road interface and which get conveyed upward and eventually to the cabin shell. The gauges of metals used will be quite a large factor too, and with the tendency for car manufacturers to reduce weight as much as possible to get improved car performance ratings, the thinner the gauges the more easily they'll vibrate, especially the larger expanses such as the floorpan and roof.

You can use tyres that are specified as being better noise-wise but experience has taught me that arguably the biggest factor is the suspension. Clearly, the tighter and taughter the suspension, the more easy it'll be for the mid and higher frequencies of the roadnoise to reach the floorpan and more generally the shell of the cabin. For example, some enthusiasts change their rubber wishbone bushings for the more durable polyurethane types, but the bad news is that these transmit more of the roadnoise upward to the cabin. Using wide tyres will also worsen the situation, since it puts more of the noise-generating interacting surfaces in contact with each other. In that regard, I've long since concluded that there's a compromise that has to be struck between a tyre's roadholding and aesthetics and the amount of roadnoise that it generates. Of course, roadnoise will vary quite wildly depending on the road's very surface. This becomes all too apparent on some motorway drives in the UK where there are sudden changes in the type of surface.

Use of Dynamat, or something equivalent, on the bigger areas of the car shell can suppress some of the higher frequency components of the noise, but not do much for the low frequency ones. Do remember, anyway, that the car comes with a good many of these paddings already factory-fitted.

Some of you might be interested in a UK firm that makes noise-suppression kits for a number of vehicles, and I think that includes the Polo. Go to http://www.nkgroup.co.uk. I think that, some years ago, NK bought out BJ Acoustics, an Oldham-based firm that specialised in providing to DIYers all sorts of anti-noise kits for cars. NK's prices are quite steep, though.
Post Reply