51–60 of 336 posts
If someone had told you that this would be the case in the 1960s, they probably would have jumped for joy. It’s more a positive signal for how much emissions technology has advanced. Obviously it’s something worth looking at and improving, still, but it’s definitely not a sign that things are getting worse, but rather the opposite.
Challenge is, can we make tired that don’t wear or are made of friendly materials.
Earlier quoted context omitted.
The numbers don't seem to add up. If an average set of tires lasts (roughly) 50,000km to 100,000km, and the average tire weights around 10kg, and you have 4 tires, then the (totally unrealistic) maximum loss per km is 4 * 10 * 1000 / 75,000 gms/km. This is 0.5g/km (and it assumed that there was no tire left). While these numbers are rough, I don't see any way to get to 5.8gm/km as quoted in the article. The brake pad…
To look at it the other direction, 5.8 g/km times 75,000 km means they have to somehow produce 435 kg of pollution per set of tires. Without some more explanation (are they building some kind of model to extrapolate to the entire supply chain?) that seems more than a little implausible. It seems most likely from the context that they are measuring shedding of brand new tires and trying to pass that off as a represent…
> Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles.
Could it be that tire wear drops off? Initially it's shedding a lot, I dunno, due to surface layer being porous or something, and then the wear drops off to the normal rate?
> Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles. So this is based on n=1, very suspicious. If tires really were this big a source of PM emissions then how would levels in US cities gone down through vehicle pollution control measures. Something is not adding up here.
Maybe offtopic but a surprising bit of extra information regarding wear and vehicles: Road wear scales with the fourth power of axle load, so heavier vehicles do much more damage than one might expect. Take a 40t truck with 5 axles vs. a small car with a weight of 1t and two axles (e.g. VW Polo, maybe an older VW Golf might only weigh 1t as well): (8t axle load / 0.5t axle load) = 16^4, i.e. the truck puts 2^16 (6553…
Worse for what? For the humans nearby? For climate change? It would be nice if such articles stated their premises.
Earlier quoted context omitted.
5.8 grams per kilometer would mean in only 10,000 KM your tyres lose 58 Kg. Seems way off.
Yep. Life of car tyre is ~40e3 km. 5.8g * 40e3km = 232 kg. Or 58 kg per tyre. A new tyre weighs about 8kg. I guess it might loose 3kg. So I think they've over estimated by about 20x.
> Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles. So this is based on n=1, very suspicious. If tires really were this big a source of PM emissions then how would levels in US cities gone down through vehicle pollution control measures. Something is not adding up here.
Maybe the article's point is to get the site's owner more testing business.