Does anyone out there know why light coloured road (beige) surfaces are much noiser than black ones ? I have heard it said that the biege ones are concrete as it's cheaper and therefore harder than tarmac, thus noiser ? There are many section of the M25 and M20 for example that use concrete surfaces, and the noise levels are much higher than the tarmac surfaces.
And to follow, any advice on a decent model of tyre that is quiet ?
|
I guess the concrete surfaces are simply rougher at the micro scale, and of course they have joints. Roll on the roll-out of the super-smooth surface that you find on parts of the M25 in its NW quadrant.
As for tyres, I'm a lifelong fan of Michelin. They may not be the quietest, but their combination of comfort and durability always seems to win out. There are some who say that the same tyre will perform differently on different cars, so it may help other respondents if you say what you drive.
|
|
No idea, you don't know what I'd give for road noise to be an issue. It simply can't compete with the engine and the rattling trim in my V70 D5.
|
One difference between concrete roads and tarmac ones is that concrete ones are less random. They have the remnants of tamping lines running all the way across at reasonably regular intervals. As the tyre traverses these more regularly spaced disconinuities, part of the noise produces is a pure tone. The near random nature of embedded chippings and aggregate within a tarmac surface does not produce a pure tone. When comparing two sources of noise with the same sound pressure level, the noise containing the pure tone is usually judged subjectively to be the most annoying.
There are available to road designers various grade of porous asphalt. Among the advantages of this material is that it gives the small, but important, trapped volumes of air between the treads somewhere else to go to, other than being expelled sideways out of the tread gaps, or sipes, as they enter the contact area. The porosity also works effectively as a dissipative absorber of sound, trapping the waves within its complex void structure. The disadvantage of porous asphalt is the cost, and the problem that it soon becomes compacted by heavy vehicles, removing its porous properties.
One of the difficulties associated with tyre noise is that the shape formed between tyre and road is very much like half of a logarithmic horn (like some PA system horns) This shape is *very* effective in enabling a sound wave to match its impedance with that of free air, and proagate effectively. In other words, the source of tyre noise is connected directly to a very effective loudspeaker horn!
In a book on tyres by LJK Setright, he describes the effect of the treads as the contact the road as if they were playing on a drum skin - i.e., the tyre!
Number_Cruncher
|
|
|
|
I'd like to know where supermarkets get their wheel squeal tarmac from! It is amazing stuff that makes tyres squeal so much even at walking pace.
teabelly
|
|
Isn't the main advantage of porous asphalt the fact that it is an excellent braking surface in the wet? Vaguely remember them testing it on that Accident Black Spot program.
|
Parts of the M40 & M25 are made of concrete, which of cause is very noisey. I think supermarket & other car park surfaces use something called "anti-skid" surface which makes the squeally sound when a vehicle goes round the corner.
--
Its not what you drive, its how you drive it! :-)
|
|
|
Isn't the main advantage of porous asphalt the fact that it is an excellent braking surface in the wet? Vaguely remember them testing it on that Accident Black Spot program.
Yes, porous asphalt also has very good drainage properties. I suppose which feature you think of as the main advantage is weather dependent!
From the acoustic perspective, however, the change in tyre noise between ordinary road surfaces and porous asphalt surfaces is dramatic.
Number_Cruncher
|
The road concrete was known as whispering concrete in the trade.
It was supposed to be a super cheap alternative to tarmac. It was trialed on the A30 near Honiton in Devon.
It is so noisey that the residents have complained to the government. If it is to be fitted on a road near you - you don't want it!
|
It is so noisey that the residents have complained to the government. If it is to be fitted on a road near you - you don't want it!
The nearby residents of the A34 between the Peartree Interchange and Weston-on-the-Green have been complaining for years about the noise of the concrete road, so much so that it's finally being dug up and resurfaced soon. Anyone that's ever travelled along that particular piece of road will know how noisy it is inside the car, let alone for the local residents.
snipurl.com/gsbf
|
|
You should see the state of the roads where i live now after supposedly being resurfaced if spraying wet tar then throwing stones on it counts!! The noise cars make now while driving along not to mention the damage to the cars!! Well at least i can here if someone is trying to nick my car now ha ha!!!
|
|
The A1/M1 link road concrete sections were replaced with tarmac just a few months after opening as local residents complained of the noise. Give me porous tarmac any day.
|
I never cease to be amazed by how road authorities don't learn. I recall concrete roads around Bournemouth in the 1950s. Very noisy then. Nothing has changed.
Have they fired a few road engineers "pour encourager les autres?". No , just let them "pour" more concrete..
:-(
madf
|
whoa ppl stop complaining because I think you're lucky after all ;)
come down to where I live and you'll soon see for yourself roads that not only are noisy but also damage various bits of suspension on a daily basis... ask 'Big Bad Dave' and I'm sure he'll second that ;)
|
|
Are you in Warsaw VdeM? Fancy a pint?
|
|
|
|
What you're driving and the tyres it's on make an enormous difference. Best I've ever had was a Xantia ('natch) but that got quieter still when I switched from Michelin to Pirelli. Don't take that as tyre advice, the world moves on. A Volvo S60 (hire car) was the worst I've driven on concrete recently. It showed up vibrations I'd never even come across before. With apologies to Volvo drivers.
John
|
I would never believe the influence tyres play in road transmission noise until I heeded H.J`s advice recently and switched from Pirelli P6000 to Michelin Pilot Primacy on my 320d. The difference is so great that it is like driving a totally different car. Whereas previously the noise from the Pirellis on concrete roads was such that you needed to turn up the radio, with the Michelins the car is now almost silent irrespective of road surface.
I would add that I have no connection with Michelin whatsoever, but merely a satisfied customer.
|
|
|
|
