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It seems all luxury cars have active suspensions now, so it's not a fair comparison to "non-active" cars. But I was recently driving a mid-2000 Mercedes E-class over the same roads I normally travel with an Acura TL and Mazda 6 of the same vintage and I was astonished at how smooth the ride was in the Mercedes.

Granted, I wasn't racing, so maybe the trade-off would be clear if I was plying each car at the track. But I'm not a passive driver, and the Mercedes did not have the "land-yacht" feel of older American luxury cars. It felt as connected to the road as the other cars, and I didn't notice more excessive roll or dive.

So what I'm wondering is: What accounts for the Mercedes' better ride? Is there something expensive that can be put in a non-active suspension that improves the ride without sacrificing handling?

My understanding is that all of these cars use the same independent suspension at the wheels, and the same sorts of springs and dampers connecting to their unibody. The particular cars I'm comparing even have roughly the same tire profiles. I'm assuming that since many tens of thousands of each model were produced that every advantage that could be "tuned in" without using more expensive parts would have been. So what could Mercedes, with more money, do to smooth out the ride that Acura and Mazda couldn't?

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    I used to sell cars at a Lincoln-Mercury dealership (many moons ago). This was about the time that the Lincoln LS came on the market. It was based off the same chassis as the Jaguar S-Type. This was a luxury car, which had luxury car ride and feel, but would corner like nobody's business. I found it to be great at both sides of the equation. My point is, if engineered correctly, you don't have to give up ride for responsiveness. Don't know if this really has anything to do with what you're asking, but thought I'd throw it out there. – Pᴀᴜʟsᴛᴇʀ2 Jul 24 '16 at 20:48
  • @Pᴀᴜʟsᴛᴇʀ2 - Yes, that's almost exactly what I'm asking: If you can give a luxurious ride without sacrificing handling, and without using an active suspension that obviously costs a lot more, then how do you do it? Is there some suspension component that costs more? E.g., for all I know that answer is, "Duh, add gas bushings for $20/corner and your Mazda will feel like a Mercedes." Or is it, "No, exact same components, but just assemble them to tighter specs?" Or is it really, "Spend 1000 more hours with the prototype mules, but yeah, otherwise all the same parts?" – feetwet Jul 24 '16 at 21:51
  • Part of what you're forgetting about the whole cost thing is this: You pay for a name. It used to be Corvettes and Camaros shared a lot of parts ... and I mean a lot. You go to the counter and ask for the Camaro part instead of the Corvette part, knowing full well the Camaro part will fit and work perfectly, yet be saving yourself 35-50% over what the equivalent Corvette part would cost. You're going to pay more for that Mercedes, partly due to the name involved. – Pᴀᴜʟsᴛᴇʀ2 Jul 24 '16 at 21:56
  • @Pᴀᴜʟsᴛᴇʀ2 - Right, but I'm asking purely about performance. I'm just observing that one out of three cars of similar design and vintage has much better road manners and wondering why. It also happened to sell for $20-30k more, so there's money that could account for the difference. But how does the money account for the performance difference? Are there specific and obviously more expensive parts? Is there a significant, more expensive design difference? Or is it just luck? E.g., "Hey, this car happens to handle beautifully, let's sell it as a Mercedes and charge a premium!" – feetwet Jul 24 '16 at 22:03
  • 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 0:07
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Assuming they were the base models, the two cars you mentioned (Acura TL and Mazda6) are both Front-Wheel Drive (FWD), while the Mercedes is Rear-Wheel Drive (RWD). The FWD cars, having both their engine and transaxle mounted over the front wheels, have a front-biased weight distribution, requiring stiffer front springs to control the weight. The higher spring rate required to retain a responsive steering feel will result in a stiffer ride.

Noise dampening will also play a role in how you perceive the ride quality. Sound insulation and robust equipment will add to the total curb weight of the vehicle. As such, the Mercedes is the heaviest of the cars you mentioned, weighing in at ~3900 lbs, while the Acura clocks in around 3700 lbs, and the Mazda at 3200 lbs. Maintaining a high level of steering feel despite the extra weight is simply a matter of tuning.

Mercedes notoriously sinks 10,000,000 £ a day (or whatever the German equivalent is, I only understand freedom units) into its Research & Development (R&D) department. Seeing as they are still in business, you can bet they have devised some pretty clever ways of making their cars feel as premium as their image suggests.

Caution: Impending sarcasm - "Abandon all hope, ye who enter here"

It's also possible, though slightly improbable, that Mercedes pulled some kind of VW style software trickery to specifically sense your keister in the seat, and soften the suspension just so you could pose this very question, gaining them internet notoriety, which is paramount to getting more money from those computer savvy millennials. Come to think of it.. how do we know you don't work for Mercedes!?

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    Illuminating observations -- thank you! Oh, and you know I'm not a shill for Mercedes because I'm not touting the revolutionary active suspensions they put on all of the luxurious, industry-leading cars you can test drive at your local Mercedes dealership today! ;) – feetwet Jul 25 '16 at 16:38
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    Thinking further, I wonder how much weight has to do with it? Years ago I loaded up a late 1990s Mitsubishi Galant with almost half a ton of gear for a long trip, and was surprised at how it suddenly rode and handled like a much better car (though of course I'm sure its emergency braking performance was impaired, and during full-throttle launches its front tires had trouble gripping the road). – feetwet Jul 25 '16 at 16:46
  • @feetwet: One of the smoothest drives I ever took was when I loaded up a half-ton pickup with a half ton of rock and drove it home. It floated over potholes that would have normally made it punch my kidneys. As you mention, acceleration was impaired a bit, but braking actually seemed to improve. – TMN Jul 25 '16 at 18:22
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    @JasonC I never said 'these are the only things that effect ride comfort'. I didn't get into suspension design because OP was looking for general vehicle parameters that could account for the differences he was feeling. I figured my mention of the MB R&D budget was enough to convey that MB values the benefits of precision tuning and design evolution. – MooseLucifer Jul 26 '16 at 13:51
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    @MooseLucifer I know. Pretend I made that comment without the MooseLucifer tag. Didn't mean to direct it at you. – Jason C Jul 26 '16 at 16:20
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As noted here:

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.

Until every unsprung component is made from the lightest exotic alloy or composite, a manufacturer could invest in lighter materials for unsprung components. Just look at the cost of wheels: Moving from steel to Mag/Al alloy to forged alloy to carbon fiber you can almost add a zero to the price of each step.

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A tuned suspension would provide a smoother ride. That would be built into the design of the car at an early stage. "Cheaper" cars would have the extra "engineering time" to do this.

It's not an expensive component, it's a more thought-out part of the design.

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    Seems like there must be more to this than just "engineering time" simply because most "cheaper" cars way outsell the expensive ones, so the cost of the engineering time would be defrayed over a much larger base and it's not like a component where there is a cost for each car. But I am not an economist… – dlu Jul 24 '16 at 20:08
  • @dlu - Exactly my point. And unless there's something novel about a car's suspension, presumably there's not a ton to discover in the industry about the design and tuning of independent suspensions for unibody vehicles. I do remember an article about the first Cadillac CTS-V noting "countless hours" spent "tuning" prototypes on the Nurburgring, resulting in a car that handles like the best German cars. But then, Cadillac had a lot to learn about producing cars that didn't float like boats.... – feetwet Jul 24 '16 at 20:17
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    Just because you and I think it makes sense doesn't mean manufacturers are going to agree. "Cheap" cars have a specific price they are aiming for, and the finished product is always a trade-off between this and that. A comfortable ride is never a high priority for "cheap" cars, since they would start competing with the mid-price and high-price entries of the same manufacturer. – tlhIngan Jul 24 '16 at 20:26
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    It's engineering economics. No company is going to spend engineering time fine-tuning the suspension of their low-end models because people who buy low-end models don't expect a silky-smooth ride. I imagine they spend much more time trying to figure out how to share parts among other models or if they can get by with spot welds instead of continuous ones than trying to determine optimal shock valving or weight balance. – TMN Jul 25 '16 at 18:31

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