5 ms·

How much does it increase friction and would this be feasible on other vehicles as well? Once electric cars are eventually here, their wheels will be the primar

How much does it increase friction and would this be feasible on other vehicles as well? Once electric cars are eventually here, their wheels will be the primary noise emitters.

kylegordon 8y ago
By looking at the animation, it appears the contact patch with the ground isn't changing. Just the same as a normal wheel then. What's changing is the internal structure and suspension.
- slavik81 8y ago
  The bending itself involves internal friction. If it didn't, you'd oscillate forever after hitting a bump. I'm not an expert on this stuff, but I would be surprised if it were as efficient as a normal wheel when on flat ground. The vibration study page states they will publish numbers on the rolling efficiency of the wheel 'soon'.
blensor 8y ago
But that is something you should not get rid of in electric cars anyway. They emit already much less noise than regular cars and are thus harder to hear by pedestrians. You don't really want super silent 1ton metal blobs moving around at 30++km/h as far as I know
- abecedarius 8y ago
  I really think I do. The traffic noise in cities makes conversation impossible almost everywhere outside (I'm hard of hearing); meanwhile public places inside that would otherwise be quiet enough get filled with music. Yes, making quiet cars safe is a challenge, but why not try solving it before assuming a bug is a feature?
- eternauta3k 8y ago
  Just put a speaker on every car playing Canon in D.
- PeterStuer 8y ago
  At 30 km/h, the car's sensors will make it stop near instant in case this is required. There is no need for insisting on noise pollution.
  - core-questions 8y ago
    Awareness of what's around you is greatly aided by a bit of noise. Given the early failures of self driving cars and what we know about mechanical reliability of normal ones, I don't think I want to pin my life or the life of my children on some automatic stop that might not work. Better to be able to get out of the way sooner.
    - PeterStuer 8y ago
      As always, it is a trade-off. Our joint use of the public streets is based on a certain trust that drivers will not try to plow into people. That doesn't mean you have to recklessly abandon all precaution, but it does mean that there are always going to be edge cases that are unmitigated. I think the vehicle based terror attacks have sadly illustrated that point. Walking the streets in a defensive mode that assumes low speed sneaking up by a driver intent to kill, or being completely oblivious to the surrounding, while at the same time driving a vehicle with defects in its core functions feels like an edge-case. The near ubiquity of people walking or cycling with headphones, or fully being fully engaged with their mobile phones seems to support that. Cars are dangerous and operated without proper care for sure, but there are very, very few injuries from ultra low speed collisions with cars. On the other hand there is enormous evidence of serious stress caused by traffic noise having an impact on health. The whole 'car noise' thing was lobbied by car-makers hoping to cash in on a 'custom ringtones for cars', modeled after the mobile phone market of the 90's. Do you believe that these random noises will avoid more deads and injuries than those created by the resulting stress and 'postal' incidents by those having to involuntarily suffer this? There are better options. Have slow moving cars emit a low powered radio or radar signal instead. Very compact and extremely low cost detectors and emitters already exist for those. Those that wish get a proximity warning without harming innocents, and as a added bonus this also works for people with reduced hearing, either because the have a hearing problem, or because they are wearing headphones. The only ones that would suffer a tiny bit are the car makers missing out on selling sounds. Can't say I'm very sympathetic to that crowd as they have amply shown a lack of responsibility and care for people's health and well-being . As usual, the benefits they want to pocket are once more blatantly oblivious to the societal downsides as they have been fully externalized for them.
- UncleEntity 8y ago
  Yep, a Prius running slowly on battery power is silent enough that people tend to just walk right in front of you since they can't hear it coming...but also makes it easy to sneak up on someone and hit them with the horn for some entertainment value, gotten quite a few friends (and jaywalkers) like that. I was talking with a blind guy a while back about the beeping crosswalk things and he was saying he had to quit walking to the corner store because the intersection didn't beep and he almost got run over too many times since he had a hard time figuring out which direction he was able to walk by listening to the car noises alone which near silent cars would only exacerbate. Probably be easier to make all the crosswalks beep instead of forcing cars to make unnecessary noise pollution but until that time...
mfgs 8y ago
Friction and noise aside, it's better to have the suspension built into the frame rather than the wheels. Added weight in the wheels adds to rotational inertia, which is harder to overcome than linear inertia. A rough rule of thumb is one kilogram in the wheels is worth two in the frame for a car in terms of acceleration.
PeterStuer 8y ago
Tire noise, mainly produced by the vibration of the tire wall, becomes the prime component in the noise production of 'regular' combustion fueled vehicles as well when you go >35km/h. In terms of noise, an electric versus a combustion car doesn't make much of a difference outside very low and in practice almost never driven speeds. When we are talking noise terrorists with car mods added specifically to pollute the audiosphere, that is different ofc.
- nasmorn 8y ago
  You mean motorcycles? I cannot understand how any stock motorcycle can be as loud as a completely modded car and be street legal to the detriment of everyone else.
  - gruez 8y ago
    because "safety"
    - PeterStuer 8y ago
      You mean in the 'loud pipes save lives" sense? That is just the same as saying "When I go for a drink, I'll first poison everyone in the bar to reduce the chance of someone attacking me"
  - PeterStuer 8y ago
    It is fairly easy to make modern engines, even when housed on motorcycles, and most certainly when mounted in cars, relatively quiet. A lot if not most of the modern car's engine noise is now made deliberately. Special noise chambers are added to amplify and shape the sound, acoustic isolation is foregone in design, and even in some cases engine noises are actually produced by speakers mounted on the vehicle.
- claudius 8y ago
  Residential streets are mostly limited to 30 km/h here and even the largest inner-city streets have a limit of 50 km/h which is rarely reached due to traffic jams, traffic lights etc.

How much does it increase friction and would this be feasible on other vehicles as well? Once electric cars are eventually here, their wheels will be the primary noise emitters.

kylegordon 8y ago

By looking at the animation, it appears the contact patch with the ground isn't changing. Just the same as a normal wheel then. What's changing is the internal structure and suspension.

slavik81 8y ago
The bending itself involves internal friction. If it didn't, you'd oscillate forever after hitting a bump. I'm not an expert on this stuff, but I would be surprised if it were as efficient as a normal wheel when on flat ground. The vibration study page states they will publish numbers on the rolling efficiency of the wheel 'soon'.

blensor 8y ago

But that is something you should not get rid of in electric cars anyway. They emit already much less noise than regular cars and are thus harder to hear by pedestrians. You don't really want super silent 1ton metal blobs moving around at 30++km/h as far as I know

abecedarius 8y ago
I really think I do. The traffic noise in cities makes conversation impossible almost everywhere outside (I'm hard of hearing); meanwhile public places inside that would otherwise be quiet enough get filled with music. Yes, making quiet cars safe is a challenge, but why not try solving it before assuming a bug is a feature?
eternauta3k 8y ago
Just put a speaker on every car playing Canon in D.
PeterStuer 8y ago
At 30 km/h, the car's sensors will make it stop near instant in case this is required. There is no need for insisting on noise pollution.
- core-questions 8y ago
  Awareness of what's around you is greatly aided by a bit of noise. Given the early failures of self driving cars and what we know about mechanical reliability of normal ones, I don't think I want to pin my life or the life of my children on some automatic stop that might not work. Better to be able to get out of the way sooner.
  - PeterStuer 8y ago
    As always, it is a trade-off. Our joint use of the public streets is based on a certain trust that drivers will not try to plow into people. That doesn't mean you have to recklessly abandon all precaution, but it does mean that there are always going to be edge cases that are unmitigated. I think the vehicle based terror attacks have sadly illustrated that point. Walking the streets in a defensive mode that assumes low speed sneaking up by a driver intent to kill, or being completely oblivious to the surrounding, while at the same time driving a vehicle with defects in its core functions feels like an edge-case. The near ubiquity of people walking or cycling with headphones, or fully being fully engaged with their mobile phones seems to support that. Cars are dangerous and operated without proper care for sure, but there are very, very few injuries from ultra low speed collisions with cars. On the other hand there is enormous evidence of serious stress caused by traffic noise having an impact on health. The whole 'car noise' thing was lobbied by car-makers hoping to cash in on a 'custom ringtones for cars', modeled after the mobile phone market of the 90's. Do you believe that these random noises will avoid more deads and injuries than those created by the resulting stress and 'postal' incidents by those having to involuntarily suffer this? There are better options. Have slow moving cars emit a low powered radio or radar signal instead. Very compact and extremely low cost detectors and emitters already exist for those. Those that wish get a proximity warning without harming innocents, and as a added bonus this also works for people with reduced hearing, either because the have a hearing problem, or because they are wearing headphones. The only ones that would suffer a tiny bit are the car makers missing out on selling sounds. Can't say I'm very sympathetic to that crowd as they have amply shown a lack of responsibility and care for people's health and well-being . As usual, the benefits they want to pocket are once more blatantly oblivious to the societal downsides as they have been fully externalized for them.
UncleEntity 8y ago
Yep, a Prius running slowly on battery power is silent enough that people tend to just walk right in front of you since they can't hear it coming...but also makes it easy to sneak up on someone and hit them with the horn for some entertainment value, gotten quite a few friends (and jaywalkers) like that. I was talking with a blind guy a while back about the beeping crosswalk things and he was saying he had to quit walking to the corner store because the intersection didn't beep and he almost got run over too many times since he had a hard time figuring out which direction he was able to walk by listening to the car noises alone which near silent cars would only exacerbate. Probably be easier to make all the crosswalks beep instead of forcing cars to make unnecessary noise pollution but until that time...

mfgs 8y ago

Friction and noise aside, it's better to have the suspension built into the frame rather than the wheels. Added weight in the wheels adds to rotational inertia, which is harder to overcome than linear inertia. A rough rule of thumb is one kilogram in the wheels is worth two in the frame for a car in terms of acceleration.

PeterStuer 8y ago

Tire noise, mainly produced by the vibration of the tire wall, becomes the prime component in the noise production of 'regular' combustion fueled vehicles as well when you go >35km/h. In terms of noise, an electric versus a combustion car doesn't make much of a difference outside very low and in practice almost never driven speeds. When we are talking noise terrorists with car mods added specifically to pollute the audiosphere, that is different ofc.

nasmorn 8y ago
You mean motorcycles? I cannot understand how any stock motorcycle can be as loud as a completely modded car and be street legal to the detriment of everyone else.
- gruez 8y ago
  because "safety"
  - PeterStuer 8y ago
    You mean in the 'loud pipes save lives" sense? That is just the same as saying "When I go for a drink, I'll first poison everyone in the bar to reduce the chance of someone attacking me"
- PeterStuer 8y ago
  It is fairly easy to make modern engines, even when housed on motorcycles, and most certainly when mounted in cars, relatively quiet. A lot if not most of the modern car's engine noise is now made deliberately. Special noise chambers are added to amplify and shape the sound, acoustic isolation is foregone in design, and even in some cases engine noises are actually produced by speakers mounted on the vehicle.
claudius 8y ago
Residential streets are mostly limited to 30 km/h here and even the largest inner-city streets have a limit of 50 km/h which is rarely reached due to traffic jams, traffic lights etc.