[Swajith]

Originally Posted by Leoshashi

If the foam stays in place and doesn't move, how will that affect tyre balance in any way? Also what about the tyres which come with foam pre-installed, will they have a similar issue? If not then how will the DIY case be any different?

Regards,
Shashi

if we can do it(DIY) as perfectly as factory does then I don't think it will effect the tyre balance.
But getting close to the factory make is what matters.

[Pontiac]

Although a simple technique and foams inexpensive, Tesla seems to have been charging the customers 2x the price of a regular tire (~$400 vs ~$200) for foam installed ones.

One of my colleagues got a flat tire on his Model X and was asked to replace the tire as it could not be repaired. He was shocked by the price of a single tire.

[vipul_singh]

Quick comment: Toyotas have this as well. I saw this mentioned in the Camry's marking communications. Not sure if it was the exact same implementation.

[Thermodynamics]

Originally Posted by Leoshashi

The Teslas and high end Mercs have been facing this issue of foam separating from the tyre on bad roads and ruining the wheel balancing. In fact Tesla recommends checking the foam first if any case of wheel imbalance is reported.

Centrifugal forces inside a tyres are insane, they say it is 1500 g’s at 180 mph. No super glue would withstand such forces, which is also the reason they stick the foam to tyre and not the rim. However, any imperfection would have to face the wrath.

[headers]

Originally Posted by dark.knight

No, runflats are about having a very thick rubber base across the entire circumference+profile of the tyre, this enables stronger sidewalls, thicker skin of the tyre such that even in an extreme flat, the tyre doesn't dip too much since the capacity of air holding is much lower in such tyres due to thicker rubber, plus the surface of rubber to be burned out is much larger and can run about 100 miles after a flat, the only caveat here is that the entire tyre has to be changed after. No fixes possible.

Wacker Chemie, an example of a company that specializes in rubber/silicone production in three specifications, i.e liquous, solid, semi-solid, can give a good idea on how to do this tyre damping by impregnating the walls during the production process, so there is no question of it coming apart so easily. Alternatively, if foam must be used, it can be used in interlocking pieces within the tyre so that failure is less.

Having worked in plastics and rubber moulding, I can say that the R&D in them are far ahead of the time, what the world experiences today isnt 5%. Car reviewers are so ignorant that they knock on economy car's interiors and grimace and say this is "plastic", so cheap and nasty. All high end car interiors have plastic too, the only difference is if they are elastomer-like plastics (properties of rubber impregnated onto plastic). Since everything is basically a polymer (two monomers), the line between plastic and rubber are becoming thin in certain grades.



The foam which is a polymer of the ONG industry as well, should be integrated at the production process, with no use of glue. Given some time even I might be able to work out a chemical chain to fuse the two depending on their composition.

Awesome points. Yes you are right about the thin line between plastics and rubberised plastics.

Sound dampeners may not be able to take the shock loads like foam, hence I would give it a skip.

The right way forward will be for tyre companies to change the compounds that might have sound absorbing as well as cushioning effect for their tyres

[dark.knight]

Originally Posted by headers

The right way forward will be for tyre companies to change the compounds that might have sound absorbing as well as cushioning effect for their tyres

Tyres are at 90% level of their maximum potential, noises are controlled like never before, even in the worst of roads but the engineers should look at cars too before the tyres :

1) Wheel-well cladding should be made of anti-acoustic material and be fully covering the well.

2) Rims shouldn't be so large that tyre sidewall height suffers, if there is no cushioning there is no damping.

3) Soft compound tyres are naturally better at low noise but have lower longevity, its one's own choice which to put in.

4.Wider the tyre width, the more of roads it has to grip onto and more noise that comes resultantly.

I'd say foam is literally useless when it comes to containing noise from tyres which is discernible by man. When a tyre goes over a pothole, there are 2 noises, the sound of the tyre actually hitting the pothole externally and the pressurized air flex and rebound of the rubber a fraction later. Foam only helps with the latter. If anything it just dampening the noise such that its more enjoyable to hear (the same effect as what the consumers say is the refined thud when closing a door, all due to damping), else the function of closing doors or tyres passing over potholes are all same. By no means will that mute the sound.

245 profile, 45 sidewall height, 19/21 inch rims and they want to lower tyre noise? If that isnt the best example of creating a solution for a made up problem, I don't know what else is.

[headers]

Originally Posted by dark.knight

245 profile, 45 sidewall height, 19/21 inch rims and they want to lower tyre noise? If that isnt the best example of creating a solution for a made up problem, I don't know what else is.

The profile and sidewall - what is the relation with tyre noise?

[dark.knight]

Originally Posted by headers

The profile and sidewall - what is the relation with tyre noise?

As I just said, wider the profile, the larger area the tyre has to grip the road surface, larger the road surface it has to grip, the more it is likely to fall into rough patches, hit or graze pebbles and tar chips and in general, simply more noise due to wider area of abrasion.

Sidewall height decreases noise and jerkiness due to the flex, wear sports shoes and see what difference it makes versus say formals that have no shock absorbing ability whatsoever and hence makes noise easily. This also depends on the compounds, but still, higher sidewall is more comfy/less noisy than lower sidewalls.

[low_rider]

Originally Posted by Leoshashi

While Conti claims reduction of upto 9dB, some real world tests show that these tyres hardly make any difference. An interesting read:

Well, I am using Continental since last 6 months on my Tata Zest, and there is a marked reduction in tyre noise compared to my stock Bridgestone B250. I can vouch for their claim, although I still need to evaluate them for long term usage.

[Leoshashi]

Originally Posted by low_rider

Well, I am using Continental since last 6 months on my Tata Zest, and there is a marked reduction in tyre noise compared to my stock Bridgestone B250. I can vouch for their claim, although I still need to evaluate them for long term usage.

The Continentals in India don't come with acoustic foam inside AFAIK. You noticed this difference mainly due to soft compound of Contis compared to B250 which is a medium compound/economy grade tyre.

Regards,
Shashi

[headers]

Originally Posted by dark.knight

As I just said, wider the profile, the larger area the tyre has to grip the road surface, larger the road surface it has to grip, the more it is likely to fall into rough patches, hit or graze pebbles and tar chips and in general, simply more noise due to wider area of abrasion.

Sidewall height decreases noise and jerkiness due to the flex, wear sports shoes and see what difference it makes versus say formals that have no shock absorbing ability whatsoever and hence makes noise easily. This also depends on the compounds, but still, higher sidewall is more comfy/less noisy than lower sidewalls.

I think its the compound more than any other factor that is the cause of the noise.

Cheers and thanks

[devsoftech]

Foam padding at the circumference will not double up as run flats. Run flats are thicker reinforced sidewalks and weigh significantly heavier due to extra material on sidewalls.

Key silent tyre design from Michelin’s and Yokohama’s was to create sipes in tread that reduces the noise. 9dB reduction claims from foams is not comparable to 20dB claimed by those sipes.

[greenhorn]

won't this mess up puncture repair? no way to put a mushroom patch on a tyre like this without removing and potentially damaging the foam.