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Comment by numpad0 | Hacker News Reader

Fun fact: electric cars make larger, not smaller, road noises.

This is because wind and tire rolling noises take over any engine noise at > 15mph, and because electric vehicles are usually substantially larger and heavier than its counterparts.

Those whooosh noise of a car passing is mostly the sound of an 1.75t object rolling through displacing air.

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That is incorrect. In different measurements the noise level was the same at higher speeds, while being much lower for EV at urban driving speeds.

One example: https://www.toi.no/getfile.php/1340825-1434373783/mmarkiv/Fo...

is 2-4db reduction under 30km/h “much lower”?

3dB lower is 50% less power. It's a small perceptual difference, but a fairly sizable difference in absolute terms.

And probably lower variance in noise compared to ice cars which are sometimes designed or modified to have excess noise as a feature.

Does the mass really affect the sound through the air? I'm sure that the shape and size of the vehicle will affect the wind noise, but I fail to see how the mass of the object directly affects the wind noise.

Tire noise, possibly, as the tire is holding that mass.

Interesting. I'm definitely looking forward to electric buses and trucks though. Standing on the sidewalk when a bus accelerates next to you can be offensively loud.

Breathing in the exhaust is worse than the sound, though.

A city in Germany (Osnabrueck) has switched all their buses to electric. They are much more silent, for sure.

I also don't feel like electric cars are more loud, at least at moderate speeds. I always had the impression that they're a lot more silent inside cities. Maybe on a highway that would be different, I can't say.

The biggest offenders of background noise are obviously trucks though.

Not where I lived, when I lived in a city. The worst offenders by far were motorcycles and cars which had aftermarket exhausts designed to be noisy. Much of the noise on roads is intentional.

> The worst offenders by far were motorcycles and cars which had aftermarket exhausts designed to be noisy.

You aren't wrong.

At what distance? I live in the country, where there often is not a vehicle moving within a mile or so, and can guarantee that when cars do come nearby, it is the engines I hear, not the wind and tires.

I hear mostly air and tires.

Are they accelerating? Or you hear them at a constant volume?

I can hear the engines very well. Unmistakeable, loud sound.

This seems wrong. Do you have a source you can cite?

I fail to see why electric cars are significantly heavier than gasoline cars. Signifikant in the sense that it makes a differenc in noise.

They have a battery that weighs much more than 15 gallons of gasoline.

There's about 500 kg of battery in the long range version of Tesla Model 3.

ICE + transmission + all the related cruft (cooling, battery, starter motor, fuel & pump) easily weigh a few hundred kilos.

The drivetrain in a Tesla has not-negligible weight. Few could lift it. Not I.

Yeah, but also they do not have a combusion engine made out of cast iron that sports a gearbox, clutch, starter, starter battery and generator.

An EV has a lot less components than a combusion car. So much so that they can add a second trunk where the heavy combusion engine normally sits.

Just take a look at the actual weight of the Tesla Model 3. It is listed between roundabout 1.600 kg and 1.800 kg which is absolutely in the ballpark of the two tons every other mid sized sedan weights. Example : Volkswagen model Passat: 1470kg - 1760kg.

wait.. electric cars are larger and heavier?

I must have missed seeing the commercial launches of all those bigger than Chrysler C's bigger than Toyota Landcruiser's, bigger than Ford F150's etc that must have been selling like hotcakes.

That claim alone is enough to discount your entire comment.

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