6 ms·

Tangent, but what's the rationale for car doors requiring slams? They are the only door I know, at least in common, daily life contexts, that require slamming t

Tangent, but what's the rationale for car doors requiring slams? They are the only door I know, at least in common, daily life contexts, that require slamming them with the force of Thor to properly close them.

sleepytimetea 4y ago
I got a new(used) car which has power closing doors - you just bring them close to the car and the motors gently pull them closed. Luxury feature because you never slam or even shut the doors anymore, they are closed soundlessly. I didn't know I wanted the feature till I got this car...now I wish all cars had this. I bet I won't feel the same when I have to pay a thousand dollars to get a single motor replaced.
sh34r 4y ago
Car doors are unlike any other door in your common, daily life contexts. They are not rectangular. They are heavy and float several inches above the ground. They have hydraulics and/or springs, and typically have two fixed points where they will remain open, even in moderately high winds. They have electronics, power windows, crumple zones, and side airbags. They lock remotely. Their latches and handles are very different from other doors. A car door is like a bedroom door in the same way a MacBook is like a Cray supercomputer. A door is a door and a computer is a computer, but there is significant variance within that category.
noizejoy 4y ago
I think one of the reasons is air pressure inside the car. I've always found it amazing how much less slamming the doors needed when a window was left wide open and the air inside the car could escape freely.
- fbellag 4y ago
  My last two (severely low end) cars had a function that opened slightly one window when there was just one door open,for this reason... To allow the last door to close without excessive force. On one of the cars it wasnt enabled from factory, but I asked the dealership and they enabled it at no cost.
- deleted 4y ago
  [deleted]
- Cyphase 4y ago
  It's fascinating how doors and windows in a house interact with air pressure. The way doors act when a window is closed versus open, how a half-out-of-frame door will open when a door to the garage on the other end of the house is opened, active central air holding an ajar door against it's frame, etc.
thereisnospork 4y ago
The solidness is an indicator of quality. Apocryphally Mercedes used to add lead weights to their doors to get that solid 'thunk'. Nowadays car manufacturers are a little more subtle at it -- there's a lot of engineering that goes into how a car door feels and sounds to give that impression which is very much intentional.
- Doxin 4y ago
  AFAIK a lot of engineering goes into the hinge to make a car door feel heavy. Meanwhile the average person can easily carry two around without too much effort.
King-Aaron 4y ago
They rarely require a slam. You can soft-close the door, then lean on the outer edge enough to engage the latch. Often, the door just isn't aligned correctly. Either it's sagged on it's hinges over time, or the latch itself needs a minor alignment/adjustment (Note that even on a lot of new cars, this still helps a lot! Not all manufacturing is perfect). Other times the rubbers can be hard and perished and it doesn't allow the mechanism to engage properly.
- deleted 4y ago
  [deleted]
dTal 4y ago
At a guess it has something to do with needing to withstand 70+ mph winds. There needs to be considerable force holding the door against its seals at all times, and in a mechanical latching system this force must come from a spring, which must be charged with energy via a good slam. However there are minivans with electronically operated sliding doors, which either power the latch allowing you to gently close the door, or (going further) powering the entire closing operation at a button push. I surmise the reason we see it moreso on minivans is because 1) it is particularly difficult to work up enough energy to properly latch a sliding door, due to losses from the 90-degree change in direction at the end, and 2) violently slamming the sliding doors on a minivan is very dangerous to children's fingers.
- PebblesRox 4y ago
  Plus they're often used by kids who might not have the body weight to give a good slam.
- dreamcompiler 4y ago
  It's not about wind pressure. It's that the door when properly closed becomes an integral, load-bearing part of the car's structure. In the event of a crash or rollover, an incompletely-closed door makes the car much weaker and less protective of the occupants.
  - deleted 4y ago
    [deleted]
  - rob74 4y ago
    It's about wind pressure only for doors that have the hinge at the back (I think those also have safety systems that prevent them from being opened while the car is moving). For the more common ones that have the hinge at the front, wind pressure will actually keep the door closed.
  - dTal 4y ago
    I'm not sure I buy this - how is load being transferred through the door? Surely not through the rubber seals, those have minimal shear strength even when compressed. That leaves the hinges, which are certainly robust enough, and the latch, which unless I'm mistaken is only designed to secure the door from opening (usually they engage with some sort of rod or peg, which can't transfer torsional or axial force (i.e. the latch is free to slide along or around the peg).
bunabhucan 4y ago
Look around the door the next time you open it. You are compressing a rubber gasket that keeps out noise/water etc. out.
mulmen 4y ago
They don’t require slamming at all. Just pull them closed. It’s really very easy. Follow through.

sleepytimetea 4y ago

I got a new(used) car which has power closing doors - you just bring them close to the car and the motors gently pull them closed. Luxury feature because you never slam or even shut the doors anymore, they are closed soundlessly. I didn't know I wanted the feature till I got this car...now I wish all cars had this. I bet I won't feel the same when I have to pay a thousand dollars to get a single motor replaced.

sh34r 4y ago

Car doors are unlike any other door in your common, daily life contexts. They are not rectangular. They are heavy and float several inches above the ground. They have hydraulics and/or springs, and typically have two fixed points where they will remain open, even in moderately high winds. They have electronics, power windows, crumple zones, and side airbags. They lock remotely. Their latches and handles are very different from other doors. A car door is like a bedroom door in the same way a MacBook is like a Cray supercomputer. A door is a door and a computer is a computer, but there is significant variance within that category.

noizejoy 4y ago

I think one of the reasons is air pressure inside the car. I've always found it amazing how much less slamming the doors needed when a window was left wide open and the air inside the car could escape freely.

fbellag 4y ago
My last two (severely low end) cars had a function that opened slightly one window when there was just one door open,for this reason... To allow the last door to close without excessive force. On one of the cars it wasnt enabled from factory, but I asked the dealership and they enabled it at no cost.
deleted 4y ago
[deleted]
Cyphase 4y ago
It's fascinating how doors and windows in a house interact with air pressure. The way doors act when a window is closed versus open, how a half-out-of-frame door will open when a door to the garage on the other end of the house is opened, active central air holding an ajar door against it's frame, etc.

thereisnospork 4y ago

The solidness is an indicator of quality. Apocryphally Mercedes used to add lead weights to their doors to get that solid 'thunk'. Nowadays car manufacturers are a little more subtle at it -- there's a lot of engineering that goes into how a car door feels and sounds to give that impression which is very much intentional.

Doxin 4y ago
AFAIK a lot of engineering goes into the hinge to make a car door feel heavy. Meanwhile the average person can easily carry two around without too much effort.

King-Aaron 4y ago

They rarely require a slam. You can soft-close the door, then lean on the outer edge enough to engage the latch. Often, the door just isn't aligned correctly. Either it's sagged on it's hinges over time, or the latch itself needs a minor alignment/adjustment (Note that even on a lot of new cars, this still helps a lot! Not all manufacturing is perfect). Other times the rubbers can be hard and perished and it doesn't allow the mechanism to engage properly.

deleted 4y ago
[deleted]

dTal 4y ago

At a guess it has something to do with needing to withstand 70+ mph winds. There needs to be considerable force holding the door against its seals at all times, and in a mechanical latching system this force must come from a spring, which must be charged with energy via a good slam. However there are minivans with electronically operated sliding doors, which either power the latch allowing you to gently close the door, or (going further) powering the entire closing operation at a button push. I surmise the reason we see it moreso on minivans is because 1) it is particularly difficult to work up enough energy to properly latch a sliding door, due to losses from the 90-degree change in direction at the end, and 2) violently slamming the sliding doors on a minivan is very dangerous to children's fingers.

PebblesRox 4y ago
Plus they're often used by kids who might not have the body weight to give a good slam.
dreamcompiler 4y ago
It's not about wind pressure. It's that the door when properly closed becomes an integral, load-bearing part of the car's structure. In the event of a crash or rollover, an incompletely-closed door makes the car much weaker and less protective of the occupants.
- deleted 4y ago
  [deleted]
- rob74 4y ago
  It's about wind pressure only for doors that have the hinge at the back (I think those also have safety systems that prevent them from being opened while the car is moving). For the more common ones that have the hinge at the front, wind pressure will actually keep the door closed.
- dTal 4y ago
  I'm not sure I buy this - how is load being transferred through the door? Surely not through the rubber seals, those have minimal shear strength even when compressed. That leaves the hinges, which are certainly robust enough, and the latch, which unless I'm mistaken is only designed to secure the door from opening (usually they engage with some sort of rod or peg, which can't transfer torsional or axial force (i.e. the latch is free to slide along or around the peg).

bunabhucan 4y ago

Look around the door the next time you open it. You are compressing a rubber gasket that keeps out noise/water etc. out.

mulmen 4y ago

They don’t require slamming at all. Just pull them closed. It’s really very easy. Follow through.