Prius Plug-In Road Noise

[HectorG]

I’ve now had test drives in four different PHV’s on different tyres - Toyo Nanoenergy J61 and Bridgestone Ecopia EP150. Unfortunately, I didn’t look to see what each car was shod with before driving them as I was unaware of the debate as to the best tyre, particularly in relation to road/tyre noise. I know that I noticed some quite pronounced tyre roar at times and was wondering if this an unavoidable feature of 15” tyres, particularly if they are of the ‘energy saver’ variety and whatever the manufacturer. 

My current RAV4 Hybrid runs on Bridgestone Ecopia H/L 422 Plus tyres and I often find the road/tyre noise on the dreadful rural roads around Dorset  almost intolerable - the whole car seems to resonate - possibly made worse by my tinnitus. I find it difficult to evaluate a car on a limited test run which is all I have been able to manage so far. In fact, only one dealer allowed me to drive the car unaccompanied.

I appreciate the lovely ride on 15” tyres with fat sidewalls and the fact that Toyota seems to be unique in not forcing you to have ultra low profile tyres on the higher spec cars. Also, I definitely felt that the PHV is generally quieter inside than my RAV4, apart front the tyre noise, which could of course appear more noticeable because of the the lack of noise from the drive train, wind etc.

Any thoughts from anyone who has experience of using both the Prius and RAV4 Hybrid over a reasonable length of time would be appreciated. Also, any advice on the merits of the Toyo 15” vs the Ecopia 15”? I know noise is in many ways very subjective (although you can of course measure dB), but I may be better off looking for a nearly new PHV with one tyre rather than the other if there is a noticeable difference. 

[altocumulus]

A nearly new PHV, with only one tyre will be extremely noisy :D

I'm informed by my lady that the winter tyres on our PHV are quieter than the originals....

[PeteB]

When I had a test drive on the new 2019 RAV4 I checked with my decibel meter, which averaged 66 dB at 60 mph and 68-9 at 70 (on dry roads) - identical to the Gen 4 2016 Prius I owned at the time.

The Prius was on 15" wheels, as was my previous 2012 Gen 3 Prius.  The Gen 3 was switched to Dunlop Sport BluResponse (Eco B Wet A 68 dB) when the original Bridgestones needed replacing, and these made the car noticeably quieter. 

[HectorG]

1 hour ago, altocumulus said:

I'm informed by my lady that the winter tyres on our PHV are quieter than the originals....

My only experience of using winter tyres was with a 2013 Subaru Forester XT which had a very harsh rise on 55 profile tyres (18” wheels) so I acquired a set of 17” wheels and fitted 65 profile winter tyres. Surprisingly little difference in either noise or ride quality.

[Ten Ninety]

As a fellow tinnitus sufferer, this was an important choice for me when I was looking. However, I didn't come to any definitive conclusion as to whether either the Toyos or the Bridgestones were better in terms of road noise. On my first test, I remember being impressed at how much quieter the PHV was compared to the Auris HSD I'd arrived in, which was similar for road noise to a Gen3 Prius (i.e. terrible). That first PHV had Toyos on. I then tested one on Bridgestones that seemed rather less impressive, so I thought the Toyos were better, until I tested another one on Toyos that seemed noisier again. I never did a back-to-back test, nor did I do any db measurements, so it's not a scientific conclusion. I ended up with a car on Bridgestones, which do generate a fair bit of noise on some surfaces, but in my experience that's the case with most modern cars.  

When I got my Lexus GS, I was lured by the promise of quiet thanks to reviewers using phrases like 'church like' and 'silent'. In reality it's nothing of the sort. Yes, the tyre noise is better suppressed than the Prius, but not by as much as I was expecting given the relative size and 'class' of car. On poor surfaces, it's still really loud. I've had three different brands of tyre on the GS over the years, none of which have made any noticeable difference to noise. 

The only vehicle I've driven recently that I could genuinely call 'quiet' regarding road noise was a Chevrolet Tahoe SUV, probably because it had about a foot between the tyres and the arches! 

[Ten Ninety]

Also Paul, if you haven't found it already, Geoff's thread here covers a lot of PHV-related stuff that you might find interesting and useful, including a few comments about road noise and the impact of switching to winter tyres (spoiler: it made things slightly worse in both cases). 

[HectorG]

1 hour ago, Ten Ninety said:

 

When I got my Lexus GS, I was lured by the promise of quiet thanks to reviewers using phrases like 'church like' and 'silent'. In reality it's nothing of the sort. Yes, the tyre noise is better suppressed than the Prius, but not by as much as I was expecting given the relative size and 'class' of car. On poor surfaces, it's still really loud. I've had three different brands of tyre on the GS over the years, none of which have made any noticeable difference to noise. 

 

Before I bought the Rav4 I tested a Lexus NX because of the claims of 'near silence'. Like you, I was disappointed and subsequently went for the Rav as I felt it was no worse. The Lexus was of course a bit posher, but at the cost of  worse mpg figures and a higher price.

[HectorG]

On 8/13/2019 at 7:58 PM, Ten Ninety said:

As a fellow tinnitus sufferer, this was an important choice for me when I was looking. However, I didn't come to any definitive conclusion as to whether either the Toyos or the Bridgestones were better in terms of road noise. On my first test, I remember being impressed at how much quieter the PHV was compared to the Auris HSD I'd arrived in, which was similar for road noise to a Gen3 Prius (i.e. terrible). That first PHV had Toyos on. I then tested one on Bridgestones that seemed rather less impressive, so I thought the Toyos were better, until I tested another one on Toyos that seemed noisier again. I never did a back-to-back test, nor did I do any db measurements, so it's not a scientific conclusion. I ended up with a car on Bridgestones, which do generate a fair bit of noise on some surfaces, but in my experience that's the case with most modern cars.  

 

Luck of the draw with tyres. I ended up with Toyos and find them very noisy - certainly worse than the Bridgestone Ecopia on my RAV4 Hybrid. However, like you I find it difficult to remember whether the Prius was worse on Toyos than Bridgestone (driven a couple or so on each) as I did t drive them back to back on the same route. I guess it’s what you should expect from ‘eco’ tyres.

I suppose it’ll be a case of looking for quieter tyres at renewal time; but that could of course be at the expense of economy. It could also involve quite a wait though, judging by how well my Rav tyres wore. Any idea what mileage you can expect from PHV tyres?

[Ten Ninety]

I don't know about tyre mileage on the PHV. It's a heavy old beast, so perhaps we should expect less than the standard hybrid.  

I have no experience of either the Bridgestones or Toyos over very high mileages but it should be in the tens of thousands of miles. The Michelins on my wife's Auris HSD were still going strong at 60,000! 

[TonyHSD]

Hi,

 Does  the low rolling resistance tyres (eco) usually quieter than the standard tyres or UHP tyres? The sportier the tyres are the more noise, more grip and less comfort, or I am maybe wrong. There are new all season  Nakook Kinergy 4s 2 that look very similar to Michelin crossclimate with good ratings for wet performance, efficiency and noise levels, I will probably try them in near future on mine or my partner’s car perhaps. 

[Ten Ninety]

16 hours ago, TonyHSD said:

Hi,

 Does  the low rolling resistance tyres (eco) usually quieter than the standard tyres or UHP tyres? The sportier the tyres are the more noise, more grip and less comfort, or I am maybe wrong. There are new all season  Nakook Kinergy 4s 2 that look very similar to Michelin crossclimate with good ratings for wet performance, efficiency and noise levels, I will probably try them in near future on mine or my partner’s car perhaps. 

Logic would suggest you are right in assuming that performance tyres would be noisier than eco tyres, but logic doesn't always apply to tyre choice. In fact, I'm not sure it's possible to draw any general conclusions about which type of tyre is quietest, or indeed to get any accurate idea of how noisy a particular tyre will be, without actually fitting them to the car and testing yourself.

On thing that can be said with certainty is that the official manufacturer noise 'ratings' on a tyre are worthless because they measure external drive-by noise, not internal cabin noise. Some tyres with a lower noise rating may actually be noisier inside, because the tread pattern might direct more noise towards the car rather than away from it.

Even reading reviews and magazine tests where they measure internal noise isn't going to yield any really useful info unless they happen to test exactly the same tyre size in exactly the same make and model of car. There are just too many variables. A quiet tyre on one car could be noisy on another, depending on which frequencies are transmitted through the different body and suspension structures. 

[QuantumFireball]

I recently just switched my front tyres from Goodyear EfficientGrip Performance to Bridgestone Weather Control A005 and despite the higher noise rating on the label (71 vs. 69 dB I think) they sound quieter inside, with more road noise coming from the back. As others have said, the measurement on the label is for external noise.

I've also heard that significant improvements can be made with the Prius and road noise by adding sound insulation to the wheel arches, maybe Dynamat or a similar product?

[HectorG]

35 minutes ago, QuantumFireball said:

 

I've also heard that significant improvements can be made with the Prius and road noise by adding sound insulation to the wheel arches, maybe Dynamat or a similar product?

 

Good shout. My local car radio specialist fits Dynamat - I think I’ll pay them a visit and get a quote. 

I’ve just remembered that I spoke to the Dynamat rep, when he happened to be at the dealers a couple of years ago, about a previous Fiat Ducato based camper van that suffered from road noise. I didn’t proceed at the time as the problem was largely overcome by  changing to a Mercedes V-Class based camper from the Fiat. Sadly, I’ve ended up with another load of problems - not a fan of German cars 😠

I’ll report back with likely cost.

[HectorG]

1 hour ago, Ten Ninety said:

There are just too many variables. A quiet tyre on one car could be noisy on another, depending on which frequencies are transmitted through the different body and suspension structures. 

I’ve been down this avenue before and changed to tyres with a lower noise rating and wasted a lot of money unnecessarily. The most cost effective solution is probably as QF suggested - adding sound deadening materials to the wheel arches.

[kithmo]

I had supposedly one of the quietest (drive by and general consensus) tyres. Michelin Primacy, on my Gen 3 when I had it and the road noise was terrible. In contrast I had Toyo Proxes on my Prius+ which were rated as a noisy tyre and they were the quietest. I have Toyo Nano energy on the Gen 4, which are nice and quiet on all but the roughest surface and are generally slagged off as a noisy tyre. These are all 17" low profile versions of the tyres.

I also have tinnitus and I think this plays a big part in how I interpret road noise, something to do with frequency and harmonic vibrations I reckon.

[Ten Ninety]

4 hours ago, HectorG said:

I’ve been down this avenue before and changed to tyres with a lower noise rating and wasted a lot of money unnecessarily. The most cost effective solution is probably as QF suggested - adding sound deadening materials to the wheel arches.

I looked at sound deadening for the GS a while back and wasn't able to get any definitive sense of whether it would deliver worthwhile improvements. There was a school of thought which suggested that a significant amount of road noise is transmitted directly through the suspension components and the body itself, as well as indirectly through the windscreen and side glass. On that basis, adding extra deadening to the wheelarches would therefore not make a dramatic difference. 

It's also worth noting that the PHV supposedly has more soundproofing than the standard Gen4, which had considerably more than the Gen3 (which really did/does have a road noise problem). Even if deadening is effective, that may mean there are fewer gains to be made than for the older models. 

However, all of the above is based on internet piffle and supposition rather than hard facts, so I'll be interested to hear what you discover. 

[Garth-1]

Whilst different tyres may have different noise levels, it's my experience that the amount of sound insulation in the car is a bigger factor than the tyres.  My Avensis is noisy-ish (Nokian all-season), my BMW 5-series is almost silent (Continental summers) and in my elderly Mercedes S-class I can't hear the (Continental winter) tyres at all.

[Harters]

11 hours ago, kithmo said:

I had supposedly one of the quietest (drive by and general consensus) tyres. Michelin Primacy, on my Gen 3 when I had it and the road noise was terrible. In contrast I had Toyo Proxes on my Prius+ which were rated as a noisy tyre and they were the quietest. I have Toyo Nano energy on the Gen 4, which are nice and quiet on all but the roughest surface and are generally slagged off as a noisy tyre. These are all 17" low profile versions of the tyres.

I also have tinnitus and I think this plays a big part in how I interpret road noise, something to do with frequency and harmonic vibrations I reckon.

I too have the Toyo's on my Excel and also only really notice any tyre noise on very open coubik surfaces.  Other than that I find them very good and will buy them again when the time comes to replace them.

[kithmo]

ISTR reading somewhere that the spare wheel well generates noise if not insulated, that might be a good place to start insulating, if you're having issues, as it's easy to access on most cars.

[Ten Ninety]

5 hours ago, kithmo said:

ISTR reading somewhere that the spare wheel well generates noise if not insulated, that might be a good place to start insulating, if you're having issues, as it's easy to access on most cars.

That's probably true, but I think the wheel well is full of Battery on the PHV! 😁

[HectorG]

 My wife informs me that the road noise is quite acceptable and less intrusive than our RAV4. Wonders will never cease. In fact, I think she may have a case now I’ve driven 400 miles +. I think I might live with the car for a few miles yet before I do anything drastic. Anyway, sound deadening to all the wheel arches will only add to the weight and increase fuel consumption!