After emissions is solved (EVs), tyres is the next big challenge in a sustainable car. Been thinking a lot about this problem. Up until I saw this video I thought it was almost unsolvable because something needs to touch between car and road. That friction will rip something loose. The fact that those microplastics are positively charged is, at least to me, very good news. Maybe micro debris from the asphalt / cement can be captured as well.
EVs actually make this problem worse because they are heavier. Both brakes and tires release toxic pollution.
While I fully admit that these are all engineering challenges that people could make progress on, there's also much simpler and more immediately actionable ways to improve this situation. Like encouraging walkable neighborhoods.
Also, while I can see various synthetic tires being an issue, is vulcanized natural rubber actually a problem? It’s starting off as tiny particles which should degrade fairly quickly.
The finished product isn’t considered toxic, but some individual ingredients are, including heavy metals like cadmium and lead, and high aromatic oils (more commonly known as polycyclic aromatic hydrocarbons or PAHs)
So, presumably non synthetic tires are actually fine. Though, it’s not clear if that was the intent of the article.
It's the brake disc. Some rust on the surface is not a big problem, but if it starts digging in to the metal mass it will cause reduced brake capacity. In Europe a car with lots of rust on the brake disc will not be certified for use (mandatory checkup every two years) until the brake discs have been replaced.
Regenerative brakes translate kinetic energy into stored potential energy, with marginal friction and resistive losses. Friction brakes translate 100% of the kinetic energy into waste heat, through abrasion.
While it's true that regenerative brakes are not frictionless, none that I'm aware of rely on friction. One could imagine using a clutch to controllably wind/unwind a spring, for example, but auto manufacturers aren't rinky-dink steampunkers and even so you'd still do everything you could to minimize clutch slippage.
This thread started when someone said ‘both brakes and tyres emit pollution’. The point was the brakes don’t when they’re regenerative. I’m sure the tyres still do. But that wasn’t what the thread was about.
This variable is a constant between both types of brakes. How is this relevant when comparing brakes? They both need it, one puts energy into a battery, the other one just heats up air due to the friction created by the system.
> Regenerative brakes rely on friction just like any other. Pollution is a given.
The article is about pollution from tires. Regenerative breaking can't cheat the laws of physics. That force has to be applied to the road through tires, just like any other form of wheel braking. And tires have significantly more mass to shed over their lives than brake pads.
EV doesn’t solve much actually. The total impact of an EV car is quite devastating on the environment, about the same as a gasoline car once you factor in manufacturing and mining and transport of lithium.
I had to replace my pair of $250 shoes every 3 to 4 months once I started running 50KM a week. The waste factor of having to throw those shoes out every time. Seems like I went though much more rubber than the 4 tires on my car over the lifetime of the tires of around 60,000KM
your shoe rubber is going to be a totally different makeup than car tires. I'm not a rubber chemist so I can't say which is worse. Running in car tires would be like running in hard soled work boots. Also I'm betting that < 1% of the population runs as much as you, whereas > 1% of the population has a car or ridses in motorized vehicles using rubber tires.
Well... not a direct answer to your question, but I was prompted to post this as a result of seeing https://news.ycombinator.com/item?id=25235772. An excerpt from the article there:
> Tires have one engineering principle that’s unlikely to change: they shed. The friction of rubber on abrasive surfaces is what allows a heavy vehicle to grip roads and stop when needed, sloughing off bits and pieces of the tire. A 2017 scientific literature search of 13 industrialized and industrializing countries found that an average car loses between a quarter kilogram and two kilograms of tire fragments annually. In the car-happy United States, the amount jumps to nearly five kilograms—or about the weight of a cat.
And does that matter? Is there a measurable impact on the environment? Not just detecting it as present; that seems certain. But then what? Does it have an affect?
I saw this story some other place earlier, and it was mentioned that 28% of plastic pollution of the oceans is tire debris.
Plastic is organic. As it breaks down, it does so in an endless variety of organic molecules. These being similar to biological molecules, they readily interact with all sorts of biological systems. Those systems have all seen a few billion years of optimisation, making it unlikely for any random interference to be beneficial.
But does it matter? The odd organism dying here and there doesn't matter. If the effect isn't quantified, then it could easily be "effectively nothing".
> A 2017 scientific literature search of 13 industrialized and industrializing countries found that an average car loses between a quarter kilogram and two kilograms of tire fragments annually. In the car-happy United States, the amount jumps to nearly five kilograms—or about the weight of a cat.[1]
I believe it is this [0] study. The losses are 0.23 to 4.7 kg/year in that paper. A newer review study from 2020 has numbers ranging from 0.2 to 5.5 kg/(capita*year). [1]
I can give you an OK estimate:
Tire tread is 8-9mm thick to start and starts to be unsafe 1/8" or 3mm so there are 5-6mm of useful tread at sale.
The diameter of a tire is ~0.5m (ok a little more) with a width of 0.25m (and fill of ~80%).
So the volume is ~0.00530.50.80.250= 0.0015m3= 1.5 liters
This lasts about 30k miles or 50k km over about ~2-3 years.
What's interesting is that the thickness of the layer deposited as it rolls (from this simplified model) 1.5E-3/(50E60.250.8)=3nm which is about 0.15nm or a monolayer.
I'm familiar with a liter. If I saw a liter of solid plastic sitting by the side of the road I'd be quite disappointed.
That's like finding 20 empty two liter bottles just lying there. (Based on a bottle using 50 grams of plastic.)
So yeah, seems like a lot to throw out every year from every car.
Put another way, if every driver threw an empty two liter bottle on the side of the road every two weeks, you'd have an equivalent amount of plastic being shed into the environment.
Tires last about 60k+ miles or 4-8yrs, and cars last about 200k+ miles. Tires lose about 1/2 inch of a 22 inch or so diameter on about a 10 inch wide tire before they go bad.
