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Inspired by comments here: I'm not the only one who has experienced an improvement in ride and road-feel with a heavily-laden vehicle. I'm recalling a long drive I made a decade ago in my otherwise crappy 1995 Mitsubishi Galant with nearly half a ton of equipment. That load turned it into a better car: Its ride went from flighty and harsh to soft and planted. It was not only more connected to the road, but its response to imperfections were more dampened – characteristics I have only seen together in much more expensive cars.

All I did was add weight to transform it from the car I had to drive into a car I wanted to drive. The question is: Why? And more particularly: Can that effect be reproduced without actually adding half a ton of unneeded weight?

We know that much weight made several changes to the vehicle:

  1. Shifted the center of mass to the rear, and lowered it a bit.
  2. Compressed the suspension.
  3. Which would have also increased negative camber.

More recently, I have taken to aligning all my cars to the limits of their negative camber specs, so I can appreciate what that does, but it doesn't nearly account for everything I experienced saddling that old sedan with weight.

I've spent plenty of time in near 50/50 RWD cars, so I know what neutral weight distribution feels like.

So I'm very convinced that whatever the weight did to the suspension had a great deal to do with the car becoming "smooth and connected." And in retrospect it seems like that would make sense: After all, with static suspension components manufacturers have to design in enough room for the vehicle to take a load up to its gross vehicle weight, without riding on the stops or pushing the wheels out of line. With a single passenger a standard sedan is half a ton shy of its design weight. Is it plausible that an unladen standard suspension allows more noise and is less connected? Or, put another way, if you knew you were never going to put more than a 200-pound passenger in a sedan, could you take the "excess" out of the suspension and expect a better ride?

closed as too broad by Jason C, Pᴀᴜʟsᴛᴇʀ2, tlhIngan, dlu, MooseLucifer Jul 26 '16 at 14:57

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • To replicate that situation, you could install shorter, progressive rate springs that are lighter rate then OEM springs when statically loaded, but ramp up when deflected to prevent bottoming out on speed bumps/potholes etc. The idea that the ride got better with higher loads may have something to do with the increased droop travel, but I can't quite put my finger on why the suspension being 1/3 of the way into it's travel/load would make for a better driving experience. Great question! – MooseLucifer Jul 25 '16 at 23:24
  • Likewise, I feel like there should be a real reason, but can't figure it out. Progressive rate springs are a standard after-market tuner thing, right? Are they typically used just to get a lower ride height (which I assume is sought for better high-speed aerodynamics and maybe cornering stability?), or do they have other known benefits? – feetwet Jul 25 '16 at 23:31
  • The "smoothness" of a ride is affected by a huge number of things; including but not limited to: characteristics of springs, dampers, center of gravity (all 3 axes), weight, sway bar geometry, strut angles, control arm geometry, steering arms, wheel base, tire size, tire pressure, tire wall thickness, and a zillion other things. As such I kinda view your suspension questions as "too broad"; it's a physical system that involves many components (e.g. "luxury" feel is way more than just weight or spring qualities). Btw you might find vsusp.com interesting as a start point. – Jason C Jul 26 '16 at 0:06
  • (The response to increased weight could be different in cars with other suspension characteristics, and can't just be simplified to "heavier = smoother".) Oh and don't forget aerodynamics at higher speeds. – Jason C Jul 26 '16 at 0:09
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    Let us continue this discussion in chat. – feetwet Jul 26 '16 at 1:39
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The smoothness of the ride is determined by the ability of the suspension to respond to changes in the road surface without affecting the body of the car. The ratio of sprung to un-sprung weight will greatly affect this. By increasing sprung weight with more luggage, your car body will have greater inertia and therefore will allow the wheels to move up and down on the road without moving the body, thus making the drive more comfortable.

  • This makes a lot of sense! – feetwet Jul 26 '16 at 13:09
  • Do not mistake "confort" for "handling", these two things are not the same. If you're argument is that additional sprung weight improved a cars handling characteristics, it's false. If you look at any performance car, weight reduction plays a massive part in the development of such a vehicle. – Steve Matthews Jul 26 '16 at 14:22
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    You may feel that it handles better because of the camber change due to suspension compression (which will increase turn-in response and mid turn stability to a degree), but the overall handling will be greatly reduced by the added mass. As Howie mentioned the increase in mass increases the cars inertia. This also means the object does not want to change direction as easily (e.g. Turning) or stop as easily (e.g. Breaking). This also puts a lot more strain on the various parts (brakes, trans, suspension, steering). So don't think that adding a lot of weight is a shortcut to upgrading your car. – kyle_engineer Jul 26 '16 at 17:38
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Presumably the bulk of the equipment was in the boot / low down. If you'd strapped it to the roof you might not have found the same improvement in handing came about.

What you had effectively done was lower the centre of gravity of the vehicle. This is the same reason that ground-up designed fire engine such as the Dennis Rapier sling their water tanks low between the axles. Traditional truck conversion based fire engines become an absolute handful when they're water tanks are full, the Rapiers handling improves.

There will be various other reasons for the improvement too such as the height of the vehicle will have been reduced, the pre-load on the springs and dampers will have been increased and possibly if the gear was in the boot, the weight distribution of the vehicle will have been centralised as you've effectively counteracted the weight of the engine and gearbox up front. However, the biggest single reason would be the lowering of the centre of gravity of the vehicle.

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