[repiret]

Do you have a citation for the vehicle weight to the fourth figure? There is about a 2X variation in the weight of the vehicles I’ve owned, but even accounting for differences in tire size, I can’t come up with a 16x difference in how often I change the tires.

Thinking about it a different way, there isn’t much difference in recommended tire pressure among the autos I’ve owned. That means that the pressure between the road and the tire is relatively constant but the surface area of contact is directly proportional to vehicle weight. For a fixed contact pressure, I am struggling to imagine a physical process by which the rubber loss is not proportional to the contact area.

[daemonologist]

The fourth power law is usually applied to deformation of asphalt roadways (here's a citation for that: https://www.researchgate.net/profile/Maxwell-Lay/publication...); I haven't heard it applied to tires before. If I had to guess I'd agree with you - I would expect a smaller exponent, particularly if the tires are designed for the given load.

[enragedcacti]

This Engineering Explained video seems pretty thorough. The short of it is that your intuition is in the right direction, its definitely not to the fourth power of weight. Vehicle weight does contribute to wear but according to Continental its less important than driving style and road curviness.

https://www.youtube.com/watch?v=hvIcVmSzSEg

[Etheryte]

Most studies I've seen on this topic agree that the amount of pollution created is not linear, and this also makes intuitive sense. The heavier your vehicle, the wider and/or larger diameter your tires need to be to give it the required amount of grip. If those bigger tires wear out in the same time as your smaller vehicle tires, you've already created considerably more pollution.

[darkmighty]

I know this figure comes from road wear. I don't know if it applies to tire wear, and indeed I suspect it doesn't, if only because tires tend to scale with vehicle weight as you mentioned. I think road wear may be associated with structural cracking of the road which may not change significantly with tire area.

[kirubakaran]

https://en.wikipedia.org/wiki/Fourth_power_law

[repiret]

That says nothing about tire wear.

[kirubakaran]

You think tire wear is less than road wear for a given load?

[repiret]

Yes.

Tire wear is caused by the surface of the tire being rubbed off through contact with the road. Most tire replacements happen because too much rubber has worn off of the contact surface.

While that happens some in the other direction, that’s not what usually causes road failure. You can tell this because pot-holes and other road failures have abrupt edges - they are not the road material until nothing is left but the earth beneath.

Roads also wear by being elastically deformed by the weight of the vehicles upon them. Eventually this deformation leads to failure of the road material, and it breaks away from the rest of the road, creating cracks and pot holes and so on.

Because the cause of failure is different, I don’t have any reason to expect the effect of vehicle weight to be the same. Moreover, unlike tire wear, its easy to hypothesize a physical reason that heavier vehicles will disproportionately wear the road: heavier vehicles will cause more deflection, and every material I have experience with will fail from repeated deflection faster if it’s deflected more.

[kirubakaran]

Thanks, that was very helpful!