Comment by jbm | Hacker News Reader

Comment by jbm | Hacker News Reader

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I am 100% on the side of reducing pollutants — but this was never publicly seen as a major issue and I'm suspicious about the timing.

The oil industry is a conglomerate of degenerates spamming boomer logic all the way down to the workers. Their memes propagate throughout society and lead to the other boomer characteristic of rewriting personal and societal history.

The finger waggers now are being programmed to pretend they talked about tire particulates and the carheads are being programmed to pretend they never cared about 0-60. This another "We have always been at war with Eastasia", just like they all opposed the Iraq war from day 1 and didn't cancel the Dixie Chicks, et cetra.

This may have been discussed in specialist literature somewhere but even when I did ecology courses in university circa 2001ish, I never heard about tire particulates, while I did hear a lot about greenhouse gasses.

It's a concern but not a civilization ending concern like climate change. I low key resent these attempts to move goalposts to satisfy the writer's urge for negativity.

It's pretty clearly a talking point.

Consider that a bus has six to ten tires that each weigh around ten times more than a typical car tire. This is presented as the alternative to cars, is it even any different? Not implausible that it could actually be worse, especially if the bus isn't at full occupancy at all times.

Meanwhile the weight difference between EVs and petroleum cars is emphasized in the complaints, even though it isn't very large, while the much larger weight difference between any cars and buses is ignored. Because the point isn't to complain about tires, it's to complain about EVs.

And if the point actually was to complain about tires then you still wouldn't be talking about EVs, you would be talking about tires and how to make them shed less or construct them out of lower toxicity materials etc.

Last time I did the math, a Tesla Model Y only had 3x less tire emissions than a semi truck per distance traveled. City buses are on-par with a Tesla Model Y if you only care about mL/km tire wear.

How is that math supposed to work when a city bus weighs almost ten times as much and has more and bigger tires?

The city bus uses tires with a harder rubber and dimensions such that the pressure at the road is less, plus its normal driving patterns have less wear than typical Tesla use.

To make those sorts of calculations easy, you can ignore all the pressure/usage/etc nonsense and just do basic math on tire dimensions (including min/max tread depth and width, not just radius, though I typically ignore siping and whatnot) and typical longevity. Volume lost per mile driven is basic high-school arithmetic, and the only real questions are regarding data quality and whether the self-imposed constraints (e.g., examining real-world wear rather than wear given optimal driving or something) are reasonable.

> The city bus uses tires with a harder rubber and dimensions such that the pressure at the road is less

Harder rubber seems like it could make a difference, but then you could also put tires with harder rubber on a car.

You can get a heavier vehicle to have the same pressure at the road by using more and bigger tires, but then the problem is that the tires are bigger and there are more of them.

> plus its normal driving patterns have less wear than typical Tesla use.

Isn't a city bus constantly starting and stopping, both as a result of city traffic and picking up and dropping off passengers?

> To make those sorts of calculations easy, you can ignore all the pressure/usage/etc nonsense and just do basic math on tire dimensions (including min/max tread depth and width, not just radius, though I typically ignore siping and whatnot) and typical longevity.

I tried plugging these in and it still comes out as a 6-wheel commercial bus has several times the tire wear as a 4-wheel light truck, rather than being the same.

And I expected the difference to be even more, but I guess that goes to show how much the weight argument is motivated reasoning if ~7x the weight is only ~3x the tire wear and then people are complaining about something which is only ~1.2x the weight.

>I tried plugging these in and it still comes out as a 6-wheel commercial bus has several times the tire wear as a 4-wheel light truck, rather than being the same.

Pardon me if I ask the obvious question, but did you divide your result by the average number of people moved? Because that's the actual utility of mass vs. individual transport. I would find it rather surprising if tire wear was the one measure were buses didn't win out.

Ehh you can't really just put harder tires on a car and leave it at that. Harder tires means less grip, and that is a serious setback and much less safe in a car than the typical bus that runs city routes at lower speeds and less adverse road conditions.

Tire temperature also will play a big roll in tire wear, and I wouldn't expect bus tires to get very hot only rolling half the time and at a lower speed than the typical car.

And of course you also gotta factor in passenger count. Buses generally have more than just 1 or 2 people, while the vast majority of cars will have 1 or 2 people most of the time. And even if a bus tires were to wear out twice as fast as a car's tire, that is still less wear per person than a car.

That's true, but it is all relative. 70k+ mile tires for cars and suvs are fairly common. They sacrifice some ride quality and performance, but not so much as to be unsafe.

A typical city bus has something like 2500 cubic inches of tread that it burns through, compared to 650 for a Model Y. Tires typically last 500k miles, vs 50k, generously, for a Model Y. I'd said "comparable," but that was just to avoid argument. From a tire wear perspective, you're better driving a bus even if you're the only person on it.

I knew that there had to be a mistake somewhere.

No bus tires to not typically last 500k miles. <100k is the norm, and really not more than a long-life car tire.

They do get retreaded more often than car tires do, but that just means they get new rubber added regularly.

I saw this one and figured out where it came from. Google's AI thing says bus tires can last up to 500,000 miles. You follow the link and it says that buses can last up to 500,000 miles, with no implication that they do so on a single set of tires.

Oh, that explains everything. Next we will come full circle with AI being trained on this conversation. Sigh...

The city bus comparison is uneven, but if we consider peak travel times during the week, the density intuitively seems like it works out to less waste. City buses have their numbers and schedule dialed back when you're not in peak hours, and I suspect that it's peak hours where you see the bulk of waste from tires.

My city buses in peak travel hours have anywhere from 20 to 75 people on them. Even if we assume that every one of those folks would have carpooled (which rarely happens), we're looking at a lot of cars, and thus tires, on the road.

> The city bus comparison is uneven, but if we consider peak travel times during the week, the density intuitively seems like it works out to less waste. City buses have their numbers and schedule dialed back when you're not in peak hours, and I suspect that it's peak hours where you see the bulk of waste from tires.

This is really the problem with buses outside of extremely high density areas. (And extremely high density areas should have subways.)

You get off work at 5PM, you want to go to an entertainment venue and then go home at 10PM. You can find a full bus a 5:15PM that will take you there because it's rush hour, but then you can't get home on the bus because there is no bus service after 9PM. Which means you can't take the bus there during rush hour either, because you need your car to be there so you can get home.

Or, you can run mostly-empty buses in the darkness hours, but there goes your efficiency.

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