– Cars used for stunts typically have custom suspensions.
– USA cars in general were shit until the Japanese showed the USA how to do it. People used to wedge rubber into the suspension springs on brand new cars because the suspensions were too loose and made creaking noises when driven off the dealer’s lot. As another example, the USA couldn’t even paint cars correctly. Only one side of the metal was painted, and the chemistry of the paint was inferior.
– USA consumers wanted to drive boats on the roads.
There was a famous “Car & Driver” article from the early 90s that concluded by saying, “The variation in body panel separation on the North American car exceeds the total separation on the Honda.”
USA domestic manufacturers lost more than 50% of USA market share, and they deserved to.
Most movies car are actually in studio on some electronic trailer, like a rodeo mechanical horse, to simulate the car rolling on street while actor can say their line without wirrying on the road. The bounciness is mostly a special effect to add more realistic effect to the stationnary car. Kinda similar to the way actor always seem to use the steering loosely
American cars at the time really did have extremely soft, long travel suspension. Body on frame construction, large engines, and extensive use of steel (especially body panels) brought the average weight of midsize sedans to well over 3500 pounds. They were also much larger and suspension technology wasn’t really a top priority unlike today, where manufacturers spend millions trying to make SUVs handle like compacts without flipping over to compensate for their top-heavy design. If you wanted an American sports car (pony cars I guess) during the 60s and 70s you would get a bigger motor, shorter gearing, and “heavy duty” suspension to stiffen things up all while still handling like shit because of the lack of tire technology. This is mostly where the term “boat” used to describe cars came from
If we’re talking big luxurious US stuff, here is a random bucket of reasons that apply to greater or lesser degrees.
Prioritization of highway comfort above all, and not really many types of road where cornering performance mattered much. If you’re wanting a car to feel like sitting on a couch at 60mph all day and you don’t have many corners, soft suspension is the way.
No real tradition of the kinds of motorsport that pushed European sports cars into lots of their handling developments.
Mediocre old cross-ply tires with tall sidewalls, making for both mushy handling AND worse ride comfort, so softer suspension would help the ride, but stiffer suspension probably still wouldn’t make them handle great.
Quite a lot of weight to control, and not all that much attention paid to keeping the centre of gravity low (compared to what you might see in lighter, sportier, more cornering focused stuff)
Big luxury cars in reasonably cheap market segments. Big luxurious European stuff of the era was generally all pretty high priced, so could afford to spend money on fancy handling stuff like hydraulic self leveling suspension etc. With a Mercedes S Class budget you can make a big car handle. With an entry level Cadillac budget those kinds of tech are probably out of reach.. (plus many of those technologies were European developed anyway)
They were a lot heavier, bigger, slower. Technology has over time improved suspensions drastically.
Old cars survived accidents, today with crumple zones people survive accidents.
Another big thing they did over time overall tire diameters got bigger. It makes for a much smoother ride everything else equal.
Better materials, technology, geometry, tighter tolerances…..
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