New tyres and sound deadening - Prius PHV

[HectorG]

Finally changed my original tyres (195/65 R15 91H) - Toyo NanoEnergy J61’s - for Michelin Primacy 4 S1’s. I spent an inordinate amount of time considering the options and my main priorities were efficiency and quietness. I read all there is to read on here about Prius tyres and in the end came down in favour of the Michelins as ATS (who are owned by Michelin) had a deal on them - £230 for 4 fitted which I felt was a good enough deciding factor.

I thought the Toyos were noisy, but I think the Primacys  may be slightly noisier, largely as a result of road noise from the rear which I was largely unaware of with the Toyos. I have to admit that I failed to IGNORE the label scores (as recommended by Jay) and chose a tyre labelled as ‘A’ for fuel economy and ‘A’ for noise. I can’t comment on economy yet as the car is largely used for local journeys, mainly running on electricity, with mpg currently at 212. However, they certainly feel more sure footed and overall probably a reasonable choice.

I’m thinking of maybe trying to reduce the road noise from the tyres by installing some sound deadening material. I won’t go overboard as the extra weight could become an issue and have a detrimental effect on fuel economy. I have a 3 year old BMW 520d touring which I bought 6 months ago (having previously said I’d never buy German or diesel!) to tow a caravan, having had to sell my camper van for health reasons. There is almost no road or wind noise and when I drive it, which is not that often, I’m amazed at what is achievable. Incidentally, the BMW runs on Michelin Cross Climates.

Initially I thought it would be sensible to start by starting with the boot floor and possibly rear wheel arches to see if something like Dynamat makes any significant improvement. Has anyone on here tried this with their Prius or have any useful relevant advice which would be much appreciated? 

 

[Cyker]

That's amazing value for Michelins - They're normally 70-80+ per tyre when I look at them!

[TonyHSD]

First thing to do imo is to double check tyre pressure on cold , let say first thing in the morning before the sun comes out. Usually when tyres are over inflated they role easily but become hard too and create a rolling noise like rumble, set to correct pressures will reduce the noise significantly. My gf full ev has Michelin tyres and on my first test drive I picked that rumble immediately in comparison with my Auris on Goodyear efficient grip performance 2, I did checked the pressures next morning and they were almost as double as what should be, but that’s seems typical for uk and new cars delivered. 👍 

[HectorG]

Thanks Tony.  
The morning after the tyres were fitted I checked the pressures and they were slightly overinflated. The comments in my post were made after driving the car with the tyres inflated to the recommended pressures. 

[Bernard Foy]

1 hour ago, Cyker said:

That's amazing value for Michelins - They're normally 70-80+ per tyre when I look at them!

That was my first reaction, what a bargain!!. I would be happy to switch off my hearing aid for tyres at that price.😃

[Cyker]

Oooh I just looked at ATS and they're doing a £50 off offer if you get 4 Michelins!  

The tyres are still very expensive, but knocking that £50 off the total if you get 4 brings it down to where I could afford to get some... but the hankooks still have lots of tread left, can't really justify it... hmmm....

...

...

*jumps into car and starts doing doughnuts and powerslides to wear down the hankooks*

 

[Bernard Foy]

12 minutes ago, Cyker said:

Oooh I just looked at ATS and they're doing a £50 off offer if you get 4 Michelins!  

The tyres are still very expensive, but knocking that £50 off the total if you get 4 brings it down to where I could afford to get some... but the hankooks still have lots of tread left, can't really justify it... hmmm....

...

...

*jumps into car and starts doing doughnuts and powerslides to wear down the hankooks*

 

I’ve always found the Hankooks a good mileage tyre.

[HectorG]

14 minutes ago, Cyker said:

Oooh I just looked at ATS and they're doing a £50 off offer if you get 4 Michelins!  

The tyres are still very expensive, but knocking that £50 off the total if you get 4 brings it down to where I could afford to get some... but the hankooks still have lots of tread left, can't really justify it... hmmm....

...

...

*jumps into car and starts doing doughnuts and powerslides to wear down the hankooks*

 

In practice you seem to get more than £50 off. The ATS manager said that the discount often equates to the ‘extras’ - fitting, balancing, valves and disposal. In my case it amounted to over £56 discount.

[TonyHSD]

1 hour ago, HectorG said:

Thanks Tony.  
The morning after the tyres were fitted I checked the pressures and they were slightly overinflated. The comments in my post were made after driving the car with the tyres inflated to the recommended pressures. 

That’s good you have checked them. For the sound proof I have nothing to say, never done anything like that myself. , perhaps will improve a bit if you add extra sound deadening material. 👍

[HughL]

The noise rating for tyres is the external noise of the tyre, and as far as I understand it lower external noise doesn't always mean lower internal noise because of variables such as sound frequencies and the direction that the noise radiates. Tyres can also get noisier as they wear. 

Finding quiet tyres is a bit of a minefield but I did notice a definite drop in noise levels inside gen 4 with 17" wheels when I changed the factory-fit Toyos for Cross-Climates. The Toyos had 16k miles on them so wear could have accounted for part of that.

[Ten Ninety]

On 12/13/2021 at 5:55 PM, HectorG said:

Initially I thought it would be sensible to start by starting with the boot floor and possibly rear wheel arches to see if something like Dynamat makes any significant improvement. Has anyone on here tried this with their Prius or have any useful relevant advice which would be much appreciated?

The PHV allegedly already has more sound deadening than the Prius ordinaire. I do remember on test drives thinking it was relatively quiet compared to a Gen1 Auris or Gen3 Prius. I'm therefore not sure adding dynamat or similar will do a lot - I think a fair amount of road noise comes through the suspension components and, I guess, the glass, neither of which can be remedied easily. However, my only practical experience with the PHV has been stuffing the entire boot full of blankets (which made chuff-all difference) so I can't contribute any useful advice really.

As reported elsewhere, my Dunlops were super quiet for a while but that's slipped away as they've worn. I'm running them at 45psi to try to claim back some of the appalling hit on economy. Upping the pressure made zero difference to the noise level but hasn't done a lot for the economy either.

I would be interested to see how the Primacies affect your electric range even if you can't measure mpg. I lost 5-6 miles off my summer range switching to the Dunlops and in winter that's now more like 8-9. Even accounting for Battery ageing over 12 months, the difference between this year's montly averages and last year's 'like for like' is shocking!

[HectorG]

16 hours ago, Ten Ninety said:

The PHV allegedly already has more sound deadening than the Prius ordinaire. I do remember on test drives thinking it was relatively quiet compared to a Gen1 Auris or Gen3 Prius. I'm therefore not sure adding dynamat or similar will do a lot - I think a fair amount of road noise comes through the suspension components and, I guess, the glass, neither of which can be remedied easily. However, my only practical experience with the PHV has been stuffing the entire boot full of blankets (which made chuff-all difference) so I can't contribute any useful advice really.

As reported elsewhere, my Dunlops were super quiet for a while but that's slipped away as they've worn. I'm running them at 45psi to try to claim back some of the appalling hit on economy. Upping the pressure made zero difference to the noise level but hasn't done a lot for the economy either.

I would be interested to see how the Primacies affect your electric range even if you can't measure mpg. I lost 5-6 miles off my summer range switching to the Dunlops and in winter that's now more like 8-9. Even accounting for battery ageing over 12 months, the difference between this year's montly averages and last year's 'like for like' is shocking!

Thanks Jay,

After some use I’ve decided the Primacies are are just ‘different’ - quieter on some surfaces than the Toyos, but noisier on others. Another factor I had failed to take into account is that a few days earlier I’d had my ears de-waxed - the first time for about 3 years, since the NHS stopped doing it. I’m now hearing much better and consequently am more aware of road noise. Clearly, partial deafness sometimes has its advantages. I really don’t think it’s a bad enough problem to consider adding the weight of sound deadening materials and thereby degrade the fuel economy.

I'm still not sure about economy though. My wife drove back from her sister’s, some 130 miles, much of which was on the M5, with no charging. She says she was driving at about 75mph and recorded 74mpg. On the previous tyres we would routinely achieve 80mpg, admittedly on longer journeys with me driving and I tend to drive at 60 to 70mph, even on the motorway. I’m sure that has quite a bearing on achieving better fuel economy.

This morning I drove about 12 miles in the rain and fog, up hill and down dale at 10°C with wipers,headlights, fog lights, hrw and heating on and was running at a Battery capacity of 23mpg. This seems poorer than usual; although I’ve not paid much attention to this recently on the old tyres, but I suspect it is worse. I will however continue to monitor mpg and report back.

[Nate47]

For my 2012 Prius I added a Dynamite knockoff in the rear only. I covered the wheel wells and entire surface under the spare and surrounding metal. The results were disappointing. I was trying to recreate the large amount of noise reduction from a time when I had the whole boot full of dense pillows. I suggest focusing sound deadening inside the front doors and front floor.

[TonyHSD]

20 hours ago, Nate47 said:

For my 2012 Prius I added a Dynamite knockoff in the rear only. I covered the wheel wells and entire surface under the spare and surrounding metal. The results were disappointing. I was trying to recreate the large amount of noise reduction from a time when I had the whole boot full of dense pillows. I suggest focusing sound deadening inside the front doors and front floor.

Sound deadening is achieved with careful selection of specific places where manufacturers attach some sound proof material. They use a instruments to measure and allocate from which points exactly the noise entering inside the cabin and attach insulation only to these places. Adding more insulation material around will make no difference and only cost money and hassle. Better door shuts seals, extra seals and thicker carpets may insulate better, but best and easiest way is to buy the quietest tyres possible and keep them at correct pressure, over inflated or under inflated tyres are noisy. 👍

[Cyker]

I think a lot of it is just to dampen resonance in the car rather than actual sound deadening; My Mk4 sometimes sounds like I left a window open  

The tyres deffo do make a difference tho' - The high frequency noise from the 17's was giving me tinnitus; It's been a lot nicer on the 15's as the noise frequency is lower and easier to tune out.

[Wooster]

Just a few thought on sound deadening...  I had a Gen 2 and a Gen 3 Prius and spent an inordinate amount of time any money trying to make them quieter.  It was largely a waste of time.  Any perceived (and without a sound level meter, it's very subjective) improvement was forgotten within a week.  I found it was also easy to make things worse - adding heavy sound deadening material can lower the resonant frequency of panels and make it more intrusive.  About the only thing I found to have a marked effect was the attention I gave to the rear wheel arches: 1) Heavy sound deadening material on the metalwork. 2) Closed Cell foam on top of the sound deadener. 3) Mass Loaded Vinyl on top of the foam.  It made an appreciable difference.  But with a few weeks the car seemed just as noisy.  

[TonyHSD]

1 hour ago, Wooster said:

Just a few thought on sound deadening...  I had a Gen 2 and a Gen 3 Prius and spent an inordinate amount of time any money trying to make them quieter.  It was largely a waste of time.  Any perceived (and without a sound level meter, it's very subjective) improvement was forgotten within a week.  I found it was also easy to make things worse - adding heavy sound deadening material can lower the resonant frequency of panels and make it more intrusive.  About the only thing I found to have a marked effect was the attention I gave to the rear wheel arches: 1) Heavy sound deadening material on the metalwork. 2) Closed Cell foam on top of the sound deadener. 3) Mass Loaded Vinyl on top of the foam.  It made an appreciable difference.  But with a few weeks the car seemed just as noisy.  

That’s very interesting and confirms what I have been thought about sound proofing a car at factory. The reason why we don’t see deadening material all over the body in white is because there is no need of it and even if it’s there it will not make any positive effect. I haven’t bothered myself to try to make it quieter but I found that best tyres for uk roads are the all season ones with V shaped patterns like Michelin cross climate or Goodyear vector 4 season., these tyres can extinguish resonance from poor road surface and rough asphalt much better than typical summer tyres like Michelin pilot or Goodyear efficient grip performance which on smooth asphalt will be quieter than all season, if you are lucky to drive on smooth asphalt anywhere in UK 👌👍

[Wooster]

13 hours ago, TonyHSD said:

he reason why we don’t see deadening material all over the body in white is because there is no need of it and even if it’s there it will not make any positive effect.

IMHO there is little sound deadening because the buying public don't demand it on mid range cars - like Toyota's.  Top end cars (think Jaguar, Mercedes) do have appropriate sound deadening as their buyers demand a quieter car.  But it's all fantastically complex and the DIY owner in his garage isn't likely to make much improvement.  For an insight, see:  bksv.com/nvh-noise-vibration-harshness

 

 

Edited April 7, 2022 by Wooster
Typo

[Dizzo]

I use Blu Response tyres on my Gen2, but there are few tyres around now with 67dba which seems to be the lowest noise rating. I know that's external noise, but it must have internal benefit, and anyway, there is no measurement for internal noise rating.
I used the self-adhesive foil-backed insulation material around wheel arches, wing panels and suspension turrets (all internal), and lined the boot with a foam-back insulation material. Definitely made an improvement. I thought about doing the doors and roof, but didn't want to disturb door cards etc and roof lining.
It's still noisy on the tar/gravel chip road surfaces however.

[Tomv]

On 4/6/2022 at 8:04 PM, Wooster said:

Just a few thought on sound deadening...  I had a Gen 2 and a Gen 3 Prius and spent an inordinate amount of time any money trying to make them quieter.  It was largely a waste of time.  Any perceived (and without a sound level meter, it's very subjective) improvement was forgotten within a week.  I found it was also easy to make things worse - adding heavy sound deadening material can lower the resonant frequency of panels and make it more intrusive.  About the only thing I found to have a marked effect was the attention I gave to the rear wheel arches: 1) Heavy sound deadening material on the metalwork. 2) Closed Cell foam on top of the sound deadener. 3) Mass Loaded Vinyl on top of the foam.  It made an appreciable difference.  But with a few weeks the car seemed just as noisy.  

As I wrote here, I can confirm that the rear wheel archers deadening works and it's quite ease and unexpensive to do.

https://www.toyotaownersclub.com/forums/topic/196341-road-noise/?do=findComment&comment=1641534

 

[Cyker]

46 minutes ago, Dizzo said:

I use Blu Response tyres on my Gen2, but there are few tyres around now with 67dba which seems to be the lowest noise rating. I know that's external noise, but it must have internal benefit, and anyway, there is no measurement for internal noise rating.
I used the self-adhesive foil-backed insulation material around wheel arches, wing panels and suspension turrets (all internal), and lined the boot with a foam-back insulation material. Definitely made an improvement. I thought about doing the doors and roof, but didn't want to disturb door cards etc and roof lining.
It's still noisy on the tar/gravel chip road surfaces however.

This is not scientific by any means, but so far my experience is the lower the noise rating of a tyre, the noisier it is in the cabin!

My theory is they engineer the tyre tread pattern to not send sound outwards, but that sound has to go somewhere, and that somewhere is inwards, into the car!

Tyres with softer rubber (e.g. all seasons) will be overall quieter tho', but you tend to pay for that with higher wear and fuel consumption.