By on September 7, 2012

Edit: Now with updated graph

So, what the heck does a manufacturer mean when they offer a ‘Sport Suspension’ and is it something you actually want? While I haven’t examined every version available, themes have carried through various makes/models, so what follows are safe generalizations. I even throw in a dyno chart!

OEMs give us lots of specs to get us warm and fuzzy about a car but the majority don’t affect your everyday, commuting-to-work driving experience. How they decide to set up a suspension does. They assume an average commute-only driver just wants a comfortable car. The enthusiast will opt for an (expected) upgrade via the sport version (with infinite colorful names). And if they happen to have a hard-core race version, that is another level all-together. What might feel fun on a 5 minute test drive (and help sell the sporty version) could get annoying (or literally painful) with ownership. Even more so with a disgruntled passenger (“I told you not to get this car!”). I believe (just as I’m writing this) that car makers know they have very little time to close a sale, like a first impression. If they can’t get your attention to begin with, they won’t capture it with pretty brochures or slick commercial spots. Your test drive experience is what will likely sell a particular package.

Fast forward to your first few months with this car; if you commute, most of the time you’re pointed straight and you really don’t want to be jostled all over the place. As I like to say (and have made a video using suspension potentiometer data to prove), there’s no such thing as a smooth road. The dampers and suspension are always working.

YouTube Preview Image

Even if most of one’s commute is a mountain road with 99 turns in 4 blissful miles, one still has to cross intersections, deal with potholes and other mundane events. Having a car that doesn’t beat you up is important, even if you’ve cultivated an immunity to the effects of poor damping. Why poison yourself to begin with?

In many sport suspensions, what you get is ‘the Illusion of Performance(IoP).’ I’d trademark it but would rather focus on the Perfect Ride! That IoP  gives your body the sensation of activity – remember that we only sense acceleration, not velocity – but a damper with sharp edges on its force profile will cause time-varying load on the tires. The effect is being jerked around, a change in acceleration over time, like being on a rollercoaster.

An ideal suspension needs to soften the edges of the road, so the tires maintain contact and you get a human body-friendly ride (via muted vertical accelerations) plus solid lateral grip (minimal change in contact patch load during cornering). If the suspension designer felt its buyers would associate roughness with speed (which younger drivers – myself included – usually do), then it’ll emphasize creating jerk via more low-speed damping). For a more sophisticated audience or more expensive car, the low and mid speed will change more smoothly (still not necessarily optimal, esp. due to less compression than the chassis could use) they will typically add more high-speed rebound while keeping high-speed bump lower.

For this article I’ll make reference to 2 suspension options available on the 99-05 Mazda Miata, with a third introduced for 04-05 years. Standard was a twin-tube damper made by Showa, then a ‘Hard S’ package which used a Bilstein monotube and ostensibly stiffer and/or lower springs. From 04-05, the Mazdaspeed Miata came with its own package that had a 1mm larger front bar, 3mm larger rear, and stiffer/slightly shorter. The dampers had been tuned even more aggressively than the Hard S but were otherwise dimensionally identical.

The graph at the top of the page shows the various rear dampers only, but the fronts follow the same trend. A few observations: notice how the standard suspension has a much more smoothly varying shape, a more constant slope from 0 to +/- 2 in/sec (negative = bump, positive = rebound in this graph and all the ones we’ll share). The slope determines how much jerk the tires and you experience. The Hard S is 50% stronger in compression @ 1 in/sec and the MSM another ~15% on top. The difference in rebound and ratio of bump to rebound is what determines the degree of jacking down. At 1 in/sec, where small, repeated movements (like any rippled road surface) will affect the dynamic ride height, the ratio is a little less than 1:1  R:B for Showa, then 1.5:1 for Hard S and about 2:1 for MSM. The ‘sportier’ suspension specialize in more immediate steering feedback, yes (turning the wheel results in movements up to ~3 in/sec at the damper in the Miata’s case). But that degrades ride quality and road holding as well. Notice that the mid and high-speed damping isn’t very much different. In fact, the Showa has a strong slope for both bump and rebound, so it would tend to resist bottoming out better than the ‘sportier’ OE, Bilstein-based suspensions! One could also argue that the Bilsteins will blow-off better, which is true but I don’t find the amount of damping to be objectionable and in fact one could almost do a rally setup which was the inverse of the OE curves and have a wicked fast, comfortable car. Yes, I’ve done this! Yes, we’ve built this for customers. How stupid fast do you want to go?

I want to make it very clear that 99% of all complaints of poor ride have to do with jacking down via excess rebound damping, potentially combined with frequent engagement of the front bump stops which gets worse due to excess rebound/jacking down.

YouTube Preview Image

Jacking down can be an automakers best friend for numerous reasons. First, you get an additional ‘jerk’ when the bump stop acts as a supplemental spring. Two, the front end will get stiffer as the bump stop engages, increasing weight transfer across that axle and inducing more understeer. So even if you chuck the car into a turn (a novice driver won’t be trail-braking), it won’t want to turn. At least, not as eagerly as you’d like. Jacking down exerts a self-corrective effect on the driver. You are going slower in turns, you’re actually driving 50 though it feels you’re doing 80 (‘wow, what a sporty ride!’). And if you have bigger sway bars, then that jacking effect causes a coupled (cross-axle) time-varying load on both tires! Holy understeer, Batman!

I don’t fault them for doing this. Putting a very capable car in the hands of an inexperienced driver could be a bad thing. But they don’t tell you that this IoP is what they’re up to and that lack of fine print has bothered me since I learned these Truths. Pricier vehicles get better suspensions though it seems there’s always room to remove a bit of understeer, to have a bit more grip and sure-footedness, a bit more confidence.  This isn’t including active suspension … although we did tune a Nissan GT-R last year using the OE Adaptronic Bilsteins. Results were very good and we could retain the Soft/Sport mode settings. It was a 2009 GT-R and the damping was definitely more biased to jacking the front down.

In the next article I’ll illustrate a few setups that have strong high-speed rebound and what effects you’d notice with that.  This will include accelerometer traces showing the strong downward (negative) accelerations which are very hard on one’s body. I’ll also continue discussing the effects of bump stops on ride and handling.

HOMEWORK! For fun, check how close your front dampers (strut or shock) are to sitting on the bump stops. Report back in the comments section! I know for certain the Mini Cooper rests on the front bump stops, the Mitsubishi Evo and Subaru WRX essentially do the same.

Shaikh Jalal Ahmad is the owner of Fat Cat Motorsports

 

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103 Comments on “Suspension Truth #2: Sport Suspensions – The Illusion of Performance...”


  • avatar
    Chicago Dude

    Is it possible to upgrade the suspension of absolutely any car out there, or are you limited to just the cars that are popular enough to have aftermarket kits?

    • 0 avatar
      MeaCulpa

      You CAN update/upgrade any suspension there is, from springs (usually available of the shelf with numbers for specific cars or available of the shelf if you buy by spec – length, force what not), to dampers and complete coilovers in the later cases cost might be prohibitive if say custom mounts and valving are required. Some of the better shops around doesn’t offer any kits per se as they will build a custom setup for every customers car, the one who operates in that fashion are usually aimed at pro or semi pro racers and the “kits” require man hours to set up, in some cases many man hours.

      So yes, a good shop/engineer can build you a kit with some sweet golden Öhlins but it might cost you more then you’ll think it’s worth.

    • 0 avatar
      Charlie84

      “Is it possible to upgrade the suspension of absolutely any car out there, or are you limited to just the cars that are popular enough to have aftermarket kits?”

      The answer depends on whether or not you think aftermarket kits represent an real “upgrade” or whether they’re just bad engineering masquerading as high-performance.

    • 0 avatar
      NormSV650

      A Miata will teaeter on it’s jack stands if not even. That’s how stiff it is along with it’s smaller than other any other convertible so comparing this to a decade old Camcord is fruitless.

    • 0 avatar

      Major improvements and the ability to customize the ride and handling to your desires depends upon the availability of a re-buildable shock, like a Bilstein.

      If that’s not the case for your vehicle, then a set of bump stops could be designed to tune the ride and handling to a lesser degree – we’ve done this for various applications re-using OE shocks or other available, less-customizable shocks.

  • avatar
    YellowDuck

    I’d be more inclined to take suspension advice from someone who labeled their axes….

  • avatar
    Shankems

    I love this type of article. Simple, but hard data with good explanation as to why it matters. If only this type of detail was available from vendors when I was looking for aftermarket suspension components!

  • avatar
    benzaholic

    If I were in the suspension or tuning industry and were more familiar with many of the terms lobbed about in this article, I may have found it useful.

    I’m not clear about what the graphs are showing or how they show it.
    Jacking down?

    I hope followup articles remember that not every automotive fan is familiar with the detailed meaning of suspension terminologies and the specific performance implications of certain suspension behaviors. Help us out.

    • 0 avatar
      Dave56

      I agree. I even went back to the first article to see if any of the terms were defined, they weren’t.

      Could you please figure on an audience that is not up all on all of the terms and define them as you go?

      Thank you. I find this type of article fascinating, but as I’m not up on all of the terminology I’m missing something.

      • 0 avatar
        racingmaniac

        Basically I think he is trying to say that with rebound force(damper resisting extension) dominating the damper behavior(being greater than compression force), once the car gets on the corner(dive, roll…etc), it stays down. I don’t know how prevalent that really is on vehicle side as I don’t actually do much ride tuning, but rebound tend to be stronger in many cases just because you will have more damping inheritly on compressive side, since spring still has some friction/hysteresis, and the spring force act against body/wheel movement anyway, whereas you are fighting spring force/gravity on rebound.

    • 0 avatar

      I disagree. It’s an advanced article.

      Suspension is not that complicated, but nobody pays attention to it, so it has this black magic reputation.

    • 0 avatar
      azmtbkr81

      Great article.

      I’ll take a crack at an explanation:

      The more rebound dampening a shock has the longer it takes to return to an extended position after hitting a bump.

      Too little rebound dampening and the shock acts like a pogo stick causing the car to bounce around and lose contact with the road. To much and the shock jacks or packs down since it can’t rebound fast enough to keep up with a rapid succession of bumps, hard cornering, etc.

      If the shock packs down enough it will cause the suspension arms to come into contact with the bump stops giving the illusion of firm suspension.

      I’ve never tuned car suspension but I often tweak and adjust mountain bike suspension which operates on many of these same principles.

      • 0 avatar

        Yes to most of this except not every car has a bump stop on the suspension arms, most if not all have them on the shock or strut shaft. Some rear suspension designs have an external hard rubber suspension limiter which is really ‘last resort’ protection vs. the primary soft, micro-cell bump stop that is actively part of cornering and large bump absorption.

  • avatar
    zerofoo

    I’ve installed Eibach’s pro system plus on a number of cars, and the very first handling change I notice is more oversteer less understeer – in every single vehicle. Factory setups seem to be tuned for lots of understeer. I guess the car company attorneys won that argument.

    Are that many car buyers really upset by the back end stepping out? Years ago when most cars were rear wheel drive, people expected oversteer – today not so much.

    The more subtle changes I’ve noticed with Eibach’s kits are less/more controlled rebound. This seems to keep the car from “wallowing about” during the bumps and dips in the road. The reduced rebound also helps with wheel hop during hard launches.

    Does any of this make the car faster? Beats me. The car definitely feels better, but unless I take the thing to the track, I’ll never know if it is actually faster.

  • avatar

    Shaikh,

    Wouldn’t setting up a car with no understeer in normal around town driving result in a car that’s a bit twitchy at speed? It’s clear from the way NASCAR drivers describe how the car can be understeering on entry and oversteering on exit (& vice versa), that you’re not likely to have a car set up perfectly for all conditions. I just gave back a review car that at lower speeds wasn’t perfect on entry in terms of how quick the turn in was but the car was superb on exit. At highway speeds the turn in was much quicker.

    ” Putting a very capable car in the hands of an inexperienced driver could be a bad thing. ”

    Baruth has mentioned this in his posts on handling. There’s a very good reason why production cars generally understeer.

    • 0 avatar
      el scotto

      That’s “tight” and “loose”, a round of wedge will take care of that. Some spring rubbers if it’s real bad :P

      • 0 avatar

        It’s a bit ironic that some comments have complained that Shaikh didn’t explain his technical terms well, considering that NASCAR network broadcasts always mention terms like tight and loose and spring rates but don’t do a particularly good job at explaining what the terms mean or how they affect handling. Most broadcasting and written stuff about racing does a similarly inadequate job, though I think that Speed TV’s F1 crew does do a decent job.

        Small wonder that many car enthusiasts don’t have a clue about suspensions and vehicle dynamics. Hence cars with big rims and messed up suspension settings. “Camber”? That’s a foreign language to lots of folks who think they know about cars because they slapped on some 22s.

        Actually, I think it’d be a good idea for Shaikh to comment on other mods you need to do when you change wheel size. The spring rate of a 30 series tire on a 20″ wheel is not going to be the same as a 60 series tire on a 16″ rim. I wonder how many custom wheel shops tell their customers they need to replace the springs too if they want to preserve something close to the factory ride if they’re putting big wheels on their car.

    • 0 avatar

      Ronnie,

      Yes – as vehicle speed increases there may be a pointing, depending upon the wheelbase, center of gravity and other effects, for the yaw rate to increase and move the vehicle out of a stable region. So, low-speed understeer can translate to higher-speed oversteer. The tuning of the dampers for high road speed almost certainly enters into the minds of any vehicle suspension engineer, plus subtle aero effects even for passenger cars.

  • avatar
    Marko

    Excellent write-up.

    Is it possible to get a Mini Cooper to ride absorbingly (without compromising handling) given its bump stop resting?

    • 0 avatar

      Thank you. Yes, it’s possible to improve ride easily by using softer / shorter front stops. We carry them through our website. The rears can be made shorter too though I typically like to go one density firmer to encourage a bit more rotation…

  • avatar
    racingmaniac

    Working with automotive dampers(passive and adaptive) in my work, I do notice that majority of the dampers are setup to have much stiffer rebound damping than compression. They use the rebound side to do more body control. So instead of stiffening the outside compression in roll they stiffen the inside rebound. And instead of stiffening the front compression in dive they stiffen the rear in rebound. I am still not entirely sure why that is done, but I can see that it might give you a bit more compliance on the loaded end to deal with extra load like bumps?

    • 0 avatar

      But that wouldn’t change the weight transfer to the loaded end. It would be compressed just as much.

      • 0 avatar
        racingmaniac

        Damper changes the rate which things happen though, and it also changes the settling response. Which is what ultimately buys you grip as tire hates an oscillatory input. For gross body motion(normal handling events) I am assuming that you want the body to take a set. Doing either way I think can get you there. Though hydraulically I think its also easier to build rebound force than compressive force.

    • 0 avatar
      cdotson

      racingmaniac,

      I’d be willing to bet that OEMs move body control to the rebound side to reduce the slope of the force/time curve experienced by the damper. A damper with high rebound damping is resisting the spring and worst gravity pulling on the mass of the unsprung wheel end as it’s suspended in the air. This isn’t much total force that can hammer against a tightly-valved damper.

      Were rebound damping to be soft and compression damping stiffer to control body motions you would have to have dampers beefy enough to swallow impacts of the entire sprung mass against a tightly valved damper. The potential force this generates is much greater, and the rate at which it is applied (the fraction of time) is theoretically the same, so this would produce a much higher strain rate and would contribute to more metal fatigue. OEM-quality dampers (not to mention other suspension components) aren’t always the pinnacle of quality and craftsmanship so they might chose to hedge for higher component durability.

    • 0 avatar
      MBella

      It’s because it is the job of the springs to absorb the compression, and the shock to dampen the rebound, to put it simply.

      • 0 avatar

        Simply put, and incorrect.

      • 0 avatar
        stuki

        Shaikh;

        Are you going to do an article on more off road oriented suspensions, or is it all sport/luxury oriented?

        No recent car has had it’s marketing mix more focused on suspension performance than the Raptor; and the more the general road quality in the US revert to it’s cattle track past, the more important the ability to deal with conditions like that will get.

        Or, if not offroad, what about performant and comfortable suspension setups for roads infested with all manners of speed bumps and potholes; aka LA roads. The only time work is done on road surfaces here, is when speed bumps are being put in. And, since the main purpose of speed bumps, is to direct traffic away from the streets those well connected enough to get speed bumps installed at taxpayers expense live on, the ability to traverse these now less logjammed roads at full speed, can be a real, practical timesaver.

      • 0 avatar
        Flipper35

        The dampers do more for overall handling than the springs. The springs support the load to put it overly simplistic.

      • 0 avatar
        MBella

        How is it incorrect. They are even technically called rebound dampers. I’m not saying that the shocks don’t have an effect on compression, but that’s not their primary function. The spring absorbs the impact, the shock dampens the suspension when it rises (rebound). Ever notice that it’s much harder to extend a shock then it is to compress it. If you were to remove the shocks from a vehicle it would still have the same ride height. And it would absorbs bumps almost identically. It would ride horribly because the wheels would be bouncing like crazy, and you would get sea sick, but the primary job of the suspension would be achieved. I realize that just because their primary function isn’t compression dampening doesn’t mean that they don’t have an effect, and that you can’t tune compression with a shock.

    • 0 avatar

      Racingmaniac, yes I see this too. It is an entry-level tuning behavior if it ends up causing worsened traction on rougher/rippled surfaces. A more sophisticated approach is to consider what would happen to the chassis dynamically due to the ‘pump up’ effects of bump/compression damping force vs. the ‘pull down’ effects of extension/rebound damping force.

      A car that uses more rebound vs. bump will tend to exaggerate surface imperfections and give less grip than one that uses more bump than rebound. You ‘feel’ more of the road in the former case (which is what most OEMs and aftermarket tuners do), but are actually slower on a real-world road.

      Stuki, most of what I’m talking about applies to off-road vehicles. In fact, as I’ve learned from Pagani Baguette and my own testing, a setup that works well in off-road/rally applications can be adapted (with intelligent changes) to tarmac/street, and rough roads in particular.

      I know LA roads, they’re not much worse than a lot of what we deal with in parts of the SF Bay Area. The key comes down to is the setup jacking down or not? Or how much can you feel the road? There’s no reason you HAVE to feel every divet, a good, grippy, comfortable suspension can absolutely keep you riding over them. The problem I see is unless/until car buyers really demand a high-grip/high-comfort setup instead of pushing ‘sporty-feel’, consumers will be forced to accept that. It may be very worthwhile for an automaker to design a rally-sport suspension that actually would be rally-capable but still give composure for high-speed driving. There may be cars out there I haven’t tested that do this, but it’s a trend that needs to start/continue.

  • avatar
    DeadWeight

    I think that while the suspension is my most important criteria in any car I’ve ever owned, whether it’s been a vanilla, faux luxury or sports car, I’m probably least technically verse about suspension systems when it comes to the major components of a motor vehicle.

    This series has been eye opening for me, and I actually have to read portions of these articles several times in order to fully comprehend what’s being stated (not because of poor writing, but because the concepts are more abstract to me than…say…port fuel injection vs. direct fuel injection).

    Great work. Great series.

    This is the kind of “stuff” that validates TTAC as unique and actually quite indispensable compared to its glossy page filled Main Stream Auto Rag competition.

    Shaikh, if you’re reading the comments and responding, I have a question for you: Although the Cadillac Catera was maligned by critics and consumers alike for a variety of reasons, I had a 2001 model for a while that my employer provided, and I found the suspension to be among the nicest, most successfully balanced, premium feeling one of any car I ever driven. Why is that and what does it say about the kind or type of suspension I prefer? Thanks.

    • 0 avatar

      DeadWeight, thanks for the compliment! In terms of the Cadillac, I did drive a CTS-V a couple years ago and was very impressed. GM pioneered ‘Flat Ride’ and I think it factors into every suspension they tune, I know Corvettes and the Solstice get/got it. Again, most OEMs who’ve been around a while know what makes a car fast vs. feel fast. You got a high-end suspension that provides too roll stiffness, likely a rear natural frequency at or under 2.0 Hz (which is about the threshold for GT cars, vs more track setups), and front frequency of 1.7-1.8 Hz. The sweetest cars I know focus on good ride frequency tuning and then add stiffness to match, with damping that’s ‘just right.’ So basically, always trust that experience when evaluating a new vehicle or potential suspension!

      MBella, to be brief and courteous, you are expressing your opinion but it’s not based in actual fact. A damper/shock absorber is NOT solely for rebound! I’ve seen / built / tested some that have far LESS rebound than compression, but that’s going to make a novice driver very afraid since they won’t get visceral feedback from the road. So OEMs/tuners give more rebound than bump across the board, which is good for safety, somewhat good for control, but bad for ultimate grip and comfort. I encourage you, if you haven’t, to please watch my ‘How Shocks Work’ video series.

      In fact, you’ve encouraged me to make a video of an ‘unbottomable’ shock, where rebound is along for the ride and compression is doing all the work :)

  • avatar
    stuntmonkey

    The article gets easier to understand if you watch the videos.

    Before F-1 became completely homogenized, you could see the difference in setups across a season. Damon Hill versus Jacques Villeneuve in the Williams… Villeneuve liked his suspension on harder side, and he always seemed to be a few tenths behind Hill the year that Damon won the championship.

    • 0 avatar
      MeaCulpa

      Bringing up Damon “down” Hill is just cruel, his demise is among the saddest things in F1, loved him, still think he was a better driver then Schumi and that he basically got out-“politicted” out of F1.

      • 0 avatar
        stuntmonkey

        To be honest, he was already accomplished by the time he got into F-1, and didn’t have that many years left in him. I think he was already 31-32 when he entered F-1, so doing the one championship within his career is quite an accomplishment. What really sank him was going to Arrows, that was a quite the poor career choice.

      • 0 avatar
        MeaCulpa

        @stuntmonkey

        His third over all hi second year was also quite an accomplishment. In his third year he should have won but a German Prick – the same prick who had been one point ahead of Hill for the championship when he went into the gravel – side swiped him straight out of the pits. I truly despise the german prick* to this day for his actions in Australia – that and the “rainmasters” probable cheating with TC – but you are right it was a poor decision going to arrows. I’m not totally sure why no other team wanted to pick up a driver with such a stellar track record.

        I always got the impression that – much in the same way the Irish cycling prick wanted to make Armstrong a hero – FIA/F1 wanted a superstar and Schummi was given a lot of leeway in achieving that goal. Just as they gave Hamilton every brake possible, letting him keep his point when the team was stripped of its point after the whole spying/cheating debacle.

        *I did like him when he was an up-and-comer in Benetton, even had a poster of him on the wall.

        F1 20%car, 20%driver, 60% politics, 100%excellent.

    • 0 avatar

      Good observation – even at the F1 level, tires provided a more compliant suspension can deliver a more grip. Actual data from these teams would likely never be released…

  • avatar
    Beerboy12

    I find this way of thinking about suspension to be much like the traditional French approach, although they were very much about comfort the cars have surprisingly good grip.
    My current car, A GTI, has surprisingly supple ride for the very little amount of travel the wheels have, so no, it’s not riding on the stops but it does find them now and then. The suspension reacts fast to bring the car body under control without being jarring and has almost zero body role.

  • avatar
    Beerboy12

    More thoughts. At the end of the day, the best suspension can be let down by a weak car body. Flexing and twisting of the frame and mounting points will limit the effectiveness of any suspension.
    And one should not forget un-sprung weight either, you know, those feather weight live axles adding mass to the parts that the springs and shocks can’t control.

    • 0 avatar
      stuki

      +1, particularly on the unsprung weight part. The lighter the unsprung components is, vis-a-vis the sprung ones, the easier the well-handling yet magic carpet ride, is to achieve. Heavy German sports sedans with aluminum/Magnesium suspension components and forged wheels, don’t achieve their ride/handling prowess solely based on quality spring and damper tuning.

    • 0 avatar

      Very true – chassis flex is a big issue with convertibles especially. Some Bimmers (E36 chassis in particular sounds like) have to worry about this, and Fox-body Mustangs are allowed subframe stiffeners for this reason.

      Re: excess unsprung weight, I remember using 17″ wheels on my ’97 Miata for about two days. The deadened acceleration was maddening. Back to 14s!

  • avatar
    -Cole-

    According to Alex Dykes, the new M6 rides like a 7-Series and handles like a fat M3. Best suspension ever?

  • avatar

    Loving this series of articles!

    Thank You!

  • avatar
    redliner

    My daily driver is a Mini Cooper S with run flat tires, and John Cooper Works dampers/springs/sway bars. I average about 100 miles per day on everything from glass smooth freeway, to crappy inner city streets where it seems an SUV would be more appropriate.

    The ride is “get sent to a Russian work camp in Siberia” HARSH. However, I am able to keep up with cars that cost three times as much on twisty tracks/roads. This has to be by far one of the harshest factory suspensions available this side of a Lotus Elise, but unlike many other “sport” suspensions, it seems like it genuinely increases performance.

    • 0 avatar
      DeadWeight

      A relative has a regular Mini Cooper and that is too harsh with the standard suspension (IMO) on Michigan roads (which suck quite badly).

      An RX-8, which punches way above its weight class (IMO) in terms of handling, is far more comfortable on the same roads.

      I’d truly love to know the hows/whys/whats that go into Mazda’s secret sauce.

      • 0 avatar
        racingmaniac

        Wheelbase for one, short wheelbase car bobs over the bumps as the time between front and rear axle hitting the same event oftentimes does not allow the suspension to settle.

      • 0 avatar
        DeadWeight

        Aha! Wheelbase actually makes quite a bit of sense, as the partial reason why (and maybe significantly so).

        Still, I suspect there’s a big difference in the shock absorbers and/or struts, as well.

      • 0 avatar
        Georgewilliamherbert

        Hmm. It would be interesting to see a comparison of Miata and RX-8 on the same road, instrumented.

        I cannot perform such tests as I don’t fit in the Miata (I would buy one for weekends but… No, sorry, don’t fit).

    • 0 avatar
      MeaCulpa

      If you ditch the runflats the next time your tiers are due for a change your ride should improve immensely. The runflats ads considerable weight and are much stiffer the a regular tier.

    • 0 avatar

      I love so much about the Cooper S, the light weight, nimble steering and torque especially (S/C or turbo’d). But the suspension is a disaster for ride comfort. Ride frequencies would be 1.7/2.0 Hz front/rear normally except the front bump stops are engaged AT REST (terrible terrible terrible!) and the rebound bias means you’re bouncing off them all the time. Softening /shortening front stops improves matters greatly and you still have excellent handling with a bit more oversteer as well. What we like and the factory is afraid of providing.

      The OE ‘Cooper S’ dampers are fairly rebound-biased and the rear is particularly bad. Rear compression is really weak which provides jacking down both front and rear.

      The Cooper we tuned started with Bilstein HDs that we built into a coilover kit. It was a street/track/STX autocross setup. We ended up using a bit too much front compression but have a more refined recipe now. Disconnected the front sway bar entirely. Talk about a slot car, that thing is wicked!

  • avatar
    ajla

    “So, what the heck does a manufacturer mean when they offer a ‘Sport Suspension’ and is it something you actually want?”

    In this piece you’re talking about performance cars like the Miata, or GT-R which have a competent base suspension to begin with.

    When you start talking about a Crown Victoria, FE1 Buick, or Avenger would making the jump to the “sport” suspension give a better result?

    • 0 avatar
      Scoutdude

      In my experience having owned Panthers with and without the HPP (handling and performance package) I can say that yes it does make a difference that is positive, and increase in responsiveness w/o making it too stiff or harsh.

  • avatar
    Mandalorian

    I actually find the sport suspension more comfortable than a “Comfort” one. For example the suspension in a Buick makes me uncomfortable and achey, but in a M3 over a long trip, I feel just fine.

    • 0 avatar
      Ubermensch

      I suspect that has more to do with the seats and not the suspension. The BMW sport seats are superb. The saggy, overstuffed lounge chairs in a Buick can’t hold a candle to a supportive sport seat.

    • 0 avatar
      stuki

      It’s probably speed dependent. Traditional Buicks drive like they were optimized for parking lot-60mph. Above 100 they’re flat out scary, and even at 70, they’re starting to require more corrective action than is ideal for long term comfort. While the M3 is a nuisance at roads bumpy enough to limit speeds to parking lot speeds, but feel solid and impenetrable at road trip speeds of 65-85.

  • avatar
    ciddyguy

    the “sport suspension” in my ’03 Mazda Protege5 is firm, but not hard, nor harsh. It had good damping for the crater like roads I often run into in Seattle or washboard roads, the ride is definitely taut, but supple.

    This means the car feels more like a go kart than it would for its size, but it is never harsh, nor does it toss me around, even at low speeds over a good bump at an entrance to some parking lots.

    In my old 1992 Ford Ranger truck, the poor beast would crash its way through potholes and such with much rattling and jostling of the occupants, but in the Mazda, not so much, and yet, the ride is a bit firmer still.

    What I DO know is the difference between the Euro and US built Fiat 500 sport suspension. The sport suspension in Europe has less travel, and thus less space to go up/down before hitting the stops. The US built cars have a bit more travel, to mitigate the frequency of hitting the stops, which in my estimation helps to harden a ride, at times, considerably.

    The US 500 Sport has a firm suspension with less body roll, but the car’s motions are WELL muted so you don’t get jostled around nearly as much on less than perfect pavement.

    The best compromise I am finding are cars like my Mazda where the suspension is firm enough to make the car feel much quicker than it probably is, chuckable, and to minimize the excess understeer, which the P5 tends to not do so readily.

    I would give credit to early Japanese and European cars for introducing a firm, but not hard suspensions 30 some years ago, allowing us to experience what a car can do when it can handle without wallowing all over the place.

    A modern car that does not do so well in washboard roads is my Mom’s 2004 Dodge Stratus, it crashes through those kinds of surfaces, rather than remain in control and not jostle the driver nearly so much.

  • avatar
    ciddyguy

    Having just now watched both videos, I am getting more of his terminology and I am beginning to see what he means by sport tuned suspension.

    I think in many ways, it’s a compromise that is going on. I’d rather had a car that has a bit firmer ride, but dampens enough to not completely rattle one’s fillings out when on rougher roads, this makes a car more liveable, but at the same time, allows the car to transmit more of the information back to the driver to provide a more dynamic driving environment.

    At least that is how I see it anyway.

    • 0 avatar

      Yes, compromise is the key. True ‘sport’ suspensions would give a lot more handling precision and only a little worse ride. I’m glad to shed light on what’s actually creating a certain ride quality and ‘feel’ and the shock absorber tuning is the biggest factor, but bump stop length and ride frequencies are important to be aware of, too.

  • avatar

    Everyone, I apologize for the non-labeled graphs and not explaining terms clearly. For those who aren’t familiar with them, please watch the
    ‘How Shocks work’ videos (as some already have – thanks!). I find it much easier to be visual with these things which also helps demystify it (it did for me). I will create a glossary article that will get updated with terms, perhaps in the next issue before continuing.

    I’m making edits and updating the first image as well, to be taken a bit more seriously ;) Y-axis (vertical scale) is force in lbs, X-axis (horizontal scale) is shock velocity in inches per second.

    • 0 avatar
      Georgewilliamherbert

      The updated graph is appreciated. It made sense from the videos, but now it helps introduce the main text and the videos more clearly. Thank you.

      Taking the step back and considering that graph and my college mechanical vibrations class, I can see your point of the post very clearly now. The dynamic system is going to seek its minimum energy point where the excitation responses are minimized, which may be at a different set point than the static, sitting unmoving set point (determined entirely by spring stiffness and geometry and weight). The shapes of the curves define the dynamic minimum energy zone; if it’s asymmetrical, that asymmetry drives the dynamic balance point (in this case down). Static force averages will resist that somewhat, so it will even out somewhere between the static and pure dynamic points, but still “below” the static ride point.

      Assuming I didn’t screw up the physics in my head, I just learned something significant from this. Thanks!

      • 0 avatar

        Beautiful explanation, thank you ! I knew there was a good engineering explanation for what we could observe. The energy dissipation can move the suspension (& chassis) either up, down, or keep it neutral. Depending upon what regions of the damper curve you’re operating in, you could get a combination.

        My gut is telling me, based on your explanation, that a good handling suspension gives you a consistent (and not too low) dynamic minimum energy point, so you can predict what the car will do from one situation to another. A comfortable suspension will keep the dynamic minimum close to the static position.

        Again, awesome framework – thank you!

    • 0 avatar
      YellowDuck

      Thanks for the graph update. I was being a bit cheeky with my complaint but it probably does help people who are math-minded to know what they are looking at.

      Great series. I have some experience with this stuff on the motorcycle side, and love it. Lots of fun over the years convincing folks that adding spring preload doesn’t make their suspension “firmer”.

      With all of the damping valving options offered by companies like Penske, a person can disappear up their own arse pretty quickly once they try to carry out their own supsension mods based on theory and testing. You have to be pretty geeky to enjoy it!

      • 0 avatar

        I appreciate cheeky ;) Yes, details (like units, labeling axes) can be important!

        At first I was very intimidated with all the tuning options, especially looking at all the piston options Penske provides. I’m not an expert in every situation, but I’m pretty confident that you likely only need a couple designs to achieve 99% of results. I bet they added new versions as their empirical and theoretical understanding improved as well. Bilstein has essentially three piston designs, one of which, the newest, is my favorite. Double digressive (something they’ve touted for ages) with the ability to tune low speed independently on bump vs. rebound…

  • avatar

    “in fact one could almost do a rally setup which was the inverse of the OE curves and have a wicked fast, comfortable car. Yes, I’ve done this! Yes, we’ve built this for customers. How stupid fast do you want to go?”

    What do you mean by this type of ‘rally setup’? I want to go stupid fast in a comfortable car.

    • 0 avatar
      Georgewilliamherbert

      I believe that what he means is a setup where the suspension dynamic response to the normal little bumps gets stiffer faster below zero, rather than above zero. Looking at the illustration all the way at the top, a conventional “sports suspension” as he’s illustrating will dynamically settle towards the middle of the steepest part of the displacement/stiffness curve. For a symmetrical displacement/stiffness, that’s at the same displacement (ride height) as static, sitting on the pavement unmoving. For asymmetrical as pictured above, the middle of the steepest point is below static ride, so it should settle “down” some and the car will squat a bit towards the pavement as it drives over bumps.

      For this “rally setup” you invert the curve asymmetry, so it’s stiffer below level and more compliant above. It will tend to rise up , getting a little more ride height, as you drive.

      Downside to me would be what this does to dynamic roll performance during cornering. You’ll get more initial rolling moment heading in to the corner because your CG will start higher. Presumably the suspension settles down in hard cornering into the bump stops, as he indicates elsewhere, but it would seem like you’d roll down into them harder and faster from the higher initial ride height.

      • 0 avatar

        Hi stevenwrichards – George nailed it. For stupid fast comfort you need to make sure you’re not getting too low a dynamic ride height vs. the damper tuning. You’ll know it’s too low when you feel like you’re bottoming out (most likely highly compressing the bump stops).

  • avatar
    Georgewilliamherbert

    Hah, I just figured out where your office is, and almost sure which cloverleaf you used in the video, 101 at Holly St, right? I daily drove sections of that cloverleaf commuting for over a year. Oh, heck yes, that #@$#@$ little bump.

  • avatar
    Pagani Baguette

    Dear Shaikh,

    I applaud you for the courage and enthusiasm you have had for years. It is very refreshing to see someone swimming this strong and for this long against the current. And yes, PhD in Curiosity is really what you have 

    Hi everyone,

    The general feel from some replies is that it is very difficult to comprehend the rebound force in a damper and how it exactly affects the ride and handling in a very dynamic way. I have found an interesting and simple way to explore how rebound affects things. It is something that everyone can do for close to no cost and then everyone’s fantasy will make the experiment either short with “a-ha moment!” or longer with finding out even more interesting nuances that will apply to cars. So here we go:

    1. Find a gym nearby. If you have 24 Hours is even better as I know they have such equipment. If you are not a member, ask them politely for few minutes pass to try a specific machine, most places will let you do so. Pay them for a day if you have to, it is really worth doing it.

    2. Find a machine called “Stair Stepper”. There are several types and some use this name for entire group of machines, but you look for precisely this: http://www.exerciseandhealthstuff.com/how-stair-steppers-work.html

    3. For those how have no idea what this is, scroll down and watch the 1 min video and see how the lady steps on the pedals, going up and down.

    4. The controls of the machine allow you to reduce or increase the force needed for the pedals to dive down under your own weight. You are basically controlling “compression” force. You are “the car”.

    5. You cannot control “rebound” on the machine – that is: the upward movement of the pedals is predetermine and the pedals move up smoothly always with a consistent resistance.

    You start operating the machine and try to get a rhythm. Be consistent if you can. Then with the controls you start reducing the “compression”. You notice how the pedals “fall” much faster than they can raise up, so that slowly moves the operating position quite low, near the bottom of the machine. If you further reduce the “compression”, you start hitting the bottom of the floor. You are bottoming out. You are “jacking down”. You are on the bumpstops…

    Now, start increasing the compression and you will notice how you start riding the machine higher and higher. When the “compression” increases more than the “rebound” force, you are now operating (dynamically standing) towards the top of the machine, hitting the upper mechanical limits of the equipment. You are “jacking up”.

    At certain point playing with the controls (resistance in “compression”) you will find a setting number that makes you “ride” the machine nicely in the middle. You have found the perfect rebound-to-compression ratio for this specific setup (meaning in this case your weight and your muscles strength). Another guy goes on your machine, the way you set it up, but he is 100 lb. heavier – now your ideal setting is too “soft” for this weight and he is slowly “jacking down”. He needs to increase the “compression” to match his scenario of weight and strength.

    I hope some of you spend some time on the machine and play with the “compression-rebound” ratio on this simple “one way adjustable damper” simulator.. A lot of food for thoughts would come up!  Hope this helps.

    Cheers everyone.

    PB

  • avatar
    jacob_coulter

    A stiffer or thicker rear sway bar is one of the easiest ways to really make the car feel like it can turn on a dime, and there’s almost zero ride penalty.

    I did that mod on a WRX I owned, and I was amazed by the boost in handling, it really takes the understeer out of it.

    For a daily driver, adding really stiff struts/shocks is probably not a good idea, especially considering you need to tune it to the spring rate to really get the maximum benefit. Some people just assume that if your teeth are rattling, it must handle really good.

    • 0 avatar

      On a AWD or FWD car, going to a bigger rear bar can definitely improve handling for relatively little ride quality penalty. Of crucial importance is how rough your roads are. By coupling the axle together more strongly you induce more lateral modes into the suspension and chassis. On a RWD sportscar like a Miata or S2000, where you’re sitting closer to the rear axle than the front, the impact of a stiffer rear bar is not a zero-sum game and usually makes ride noticeably worse.

  • avatar
    krhodes1

    Isn’t this article a repost from a couple days ago? Excellent series regardless.

    This whole concept is something I have always suspected about “sport package” BMWs – they FEEL like they can corner better and handle better, and they are certainly very bumpy, but I doubt they are any faster around corners in the real world, and probably slower on a typical bumpy back road. Any cornering improvement is likely due to the better tires that come with the Sport Package. Put the same tires on the regular suspension and you would probably go faster. And the since the Sport Package cars come with staggered wheel widths, they have even MORE understeer! *&%*&^*^ lawyers!

    • 0 avatar

      To the extent the stiffer shocks / sways / springs reduce compliance on a rough road, yes a ‘sport’ suspension may be hype. However, on many vehicles that have poor suspension geometry (like McStrut Bimmers)any added roll resistance can give a measurable increase in grip. You may not like the ride quality penalty though. So for Bimmers and similar sportscars/sedans, you may be getting some marketing hype but also some speed. Best to dispense with the hype and roll with the Truth!

  • avatar
    Ryoku75

    Under regular driving, to soft suspensions last longer than stiff?

    I get the feeling that stiff suspensions aren’t very good for a cars interior.

    • 0 avatar

      I don’t think durability of the suspension is really the issue, although you are probably causing faster wear to bushings if the dampers are too stiff. When I’ve added stiffer springs/sways to my cars, new creaks seem to appear in short order. Most of my vehicles have been convertibles mind you.

  • avatar
    stuntmonkey

    Thanks for the update.

    >Report back in the comments section! I know for certain the Mini Cooper rests on the front bump stops, the Mitsubishi Evo and Subaru WRX essentially do the same.

    I’ve been to a few Mini test events… it’s a great car if you drive it on a pylon course set up on an abandoned airstrip course… And yes, during these promo events, 50 does feel like you’re doing 80.The car feels like a hero if you drive it like a hooligan. They also juice the cars with sticky rubber as well.

  • avatar
    frizzlefry

    My previous 2004 A6 S-Line had a “Sport Suspension”. I loved the car, HATED the suspension. Really, most stock Audi suspensions are stiff compared to most other cars to begin with let alone when Audi makes them “sportier”. The suspension on my A6 felt like I was riding on steel rods. It felt sporty for sure but in the city the ride was punishing. My current 3.2 A3 S-Line has a magnetic sport suspension. It is night and day. It is responsive and constantly adjusts to maintain optimal contact with the road. It’s very firm but when you hit potholes etc they soften to take edge out of it so I never get abused on rough roads. There is a button on the dash that puts it in sport mode, that firms it up noticeably and feels more like a normal firmer than hell sport suspension so I usually only turn it on when I am on the highway. Wish they had the magnetic suspension on more models; don’t think I could go back to a standard one.

  • avatar
    Trend-Shifter

    Great stuff, thanks! Your head must just be buzzing with all that brain power at work.

    I watched some of the You tube videos. This sure is fixing some of my misconceptions.
    For one thing I always thought that hitting the bump stops meant that you did not have the suspension set-up right.
    I will need to learn more.

    Question 1: Is the shocks resistance curve more controlled by speed or the amount of travel in most shock designs?

    Question 2: I was planning to add a Mustang II suspension to my Volvo 1800ES. I can get all kind of “off the shelf” things such as performance brakes, drop spindles, fast rack & pinions, tubular arms, coil overs, etc. The wideth also works out. Is the geometry good on these Mustang II front ends to use as a base to set-up the front end for curvy road performance, touring, and maybe a once a year track daze?

    • 0 avatar

      Glad you’re enjoying this! The force generated by the shock depends upon the internal construction and what speed the shock is being asked to move. In cases I’ve worked with, the amount of available travel doesn’t affect the shock force.

      I wish I could comment on the Mustang II suspension. I bet there are others who’ve already done this. You could send the shock to me for evaluation and I could tell you what they’d feel like in the car.

      I generally design a suspension to match the amount of grip the tire will produce, will usually depends upon the sidewall stiffness. But as long as you aren’t running around on a horribly stiff, over-inflated tire, the tire itself makes less ride impact than other elements of the suspension, like the shocks and spring rates.

  • avatar
    Trend-Shifter

    One more comment…

    The tire sidewall height and stiffness sure seems to have a major impact on the function of the shock.

    So I would think that you must start with your tire, then work your way through the suspension when tuning.

    Frue or Talse?

  • avatar
    carmandan

    In 2005 I bought an Infinity G35. I wanted the manual transmission but could only get it in a package that included the sport suspension and 19″ wheels with very low profile tires. Big mistake. The car handled very well but would beat you to death due to the stiff rough ride. Something you don’t notice on a short test drive but really shows up later. I later rode in an automatic trans.version with standard suspension. Totally different. I loved everything about the G35 except the ride. I eventually traded it in on a Toyota truck which actually rode much better than the Infinity.

    • 0 avatar

      I absolutely feel your pain! My brother owned an E46 M3 which rode and handled wonderfully (I never got to drive it, the b*stard!), then reluctantly sold it and bought a 350Z. Same basic suspension as the G35, and very rough ride. When I later dyno’d a set of OE G35 shocks, I saw a sharp (but weak) bump knee at low speed and stiff rebound. Recipe for pain. My Dad’s Acura TL was the same and I wish they’d bought the Accord instead. One of these days we’ll tune the Accord shocks we have laying around and do a test in the TL!

  • avatar
    NMGOM

    Shaikh,

    This article is an outstanding piece of work. Yes, the “damper” concepts may be difficult to understand, particularly in conjunction with the effects of springs, roll-bars, and tires. It is no wonder that the total picture of “suspension tuning” is as much a black art as it is a science. And the videos help a lot. Thank you.

    Cars are almost always tested for what I call “horizontal performance”. You know: acceleration, braking, skid-pad, slalom, and so on. But what is missing is exactly the type of “vertical performance” that your data suggest, EXCEPT applied to various points on the car. These data would in fact be a quantitative measure of that elusive “ride quality” that everyone talks about, but which has been so subjective.

    If some sort of accelerometer (like a seismometer for earthquakes) where attached to the following places on a car, it would do just that:
    1) The lower suspension arm, where it is attached to the wheel;
    2) The floor on the passenger’s side (or a side panel on the car);
    3) The passenger’s seat itself, on the cushion.

    It should not take too much guessing to see that the first tells you what the suspension has to deal with; the second tells you what the car has to deal with; and the third tells you what the human has to deal with. Some of the motion-vs.-time traces you have shown, their maxima, and their slopes, could be quantified for measurements in all three cases.

    But what about standard test roads?

    I suggest three things:
    1) A straight smooth concrete road with 1/2-inch high by 1-inch wide metal bars going straight across it, separated by 20 feet. There could be 10 such bars. These would simulate severe expansion joint or tar-strip conditions on real roads;
    2) A straight smooth concrete road with 2-inch deep by 1-foot long metal trenches or troughs embedded into the concrete, running half-way across the road, but then staggered with another trench coming from the other side. Each half-trench could be separated by 20 feet. This would be meant to measure, not surprisingly, pot holes (mild ones at that!).
    3) An undulating straight road surface with sinusoidal “waves” that are perhaps 3 inches high and have a wavelength of 10 feet. 10 such cycles could be molded as concrete into the concrete road. These would measure the ability of the vehicle to handle larger scale, uneven road surfaces;

    Perhaps the testing could be done for:
    1) City speeds, say about 30 mph;
    2) Back-road highway speeds, say about 60 mph.

    I had written these suggestions, and the concept of “vertical performance”, to two prominent car magazines. Response? None. Unless I am self-deluded, it seems that this type of testing would largely answer the issue of what ride quality is. What do you think?

    —————–

    • 0 avatar
      cdotson

      NMGOM, I think you’re right that given some of the instrumented testing that many media outlets perform it would be easy to conduct an objective evaluation of ride quality.

      When I worked on development of off-highway vehicles part of their ride development was a competitive evaluation of ride comfort. One technician drove all vehicles over the same course while sitting on what I like to call the “asserometer.” This was a vertical accelerometer encased in a pancake of polyurethane foam that was placed on the driver’s seat and recorded during the test. It was always interesting to look at the data.

    • 0 avatar

      This testing configuration sounds very do-able and would be extremely insightful. If we can get a number of cars together in the Bay Area, we could put together an FCM/TTAC Suspension Test Plan. We have a track of sorts and there are certain roads I know well. George Herbert is in this area also, along with Pagani Baguette.

      In fact, I’ve been looking for a mobile app designer to help create a free app to help others evaluate their vehicle suspensions. If anyone is able/willing to help out with this, let me know. I plan to make the app available and contribute my knowledge to its framework, so free coding would be the other element of this.

  • avatar
    Lightspeed

    I recall driving a lot of GM’s cars with F-41, FE-3 and WS-6 suspensions when I worked in a Pontiac dealership. I found you could really hustle these things in a corner, but on the straights they had a weird tendency to crash over minor tar strips on the road and at the same time wallow over gentle undulations. They were only happy when you had the car settled in a turn, then they were awesome.

    • 0 avatar

      Hmmm the crashing over tar strips sounds like more rebound vs bump. The wallowy behavior in transients probably due to more roll stiffness than the dampers were designed to handle, so the low speed damping was not high enough to handle the stiffer sway bars of the performance package. Possibly they left the same shocks but upped springs and sways, or just sways?

      In a steady-state/sweeper position the dampers aren’t doing much so it’s about the overall roll stiffness which was high enough to give control/confidence.

  • avatar
    Pagani Baguette

    How do you guys post pictures into the replies? Is it actually possible? I have so many graphs and diagrams which could answer so many of the questions here, but I have them on my computer and so I can’t post a link. It will be much better if the shots are posted, so it will be easier to read and refer to the drawings, etc. If there is a way to post pictures, please let me know how (reply here or just send me an email). Thanks!

    • 0 avatar
      NMGOM

      Thank you for bringing this up, Pagani..

      I sent in a request to the “Contact” link in TTAC about a week ago, on this very same topic. I asked if we all could post simple “.jpg’s”, since almost any document can be turned into a screen grab for this purpose.

      Have not heard back yet; maybe their “IT” people are working on it. But I too would have several plots, diagrams, and/or photos that could help explain things, if this capability were available. (Example from my “Vertical Performance” Test Roads: diagrams of each of the three configurations.)

      I see that “Jalopnik” does allow this capability. So, If you also write in to the TTAC “Contact”, and if others do so too, then maybe TTAC can be encouraged to figure a way to get this urgent need to happen! (Hopefully, they won’t have to go to Facebook to get it done. Just allow it right here in this “html” field.)

      ————–

      • 0 avatar
        Pagani Baguette

        Hi NMGOM,

        Just sent a message and a link to this thread through “Contact”, too. Hopefully we will be allowed to post pictures and if not, I will be happy even with hyperlinks, so we can go upload the pictures to a server somewhere and just link the pictures to the posts here to be displayed. Let’s hope we make progress soon :-)

        PB

  • avatar

    Everyone, I LOVE the sharing that happens in the comments! I will respond later this weekend, doing some website improvements the past few days (lie: past few months!) and want to release a new, sleeker more user-friend homepage by Monday. Lots to reply to, this definitely keeps my creative juices flowing and glad to see all the added insights from your collective experience.

    Not every (sport) suspension is created equal so being able to actually evaluate a new vehicle with useful sensor data is very helpful and fairly easy. We have an AiM EVO4 data system and a lab-grade 3-axis accelerometer we could gather data from multiple locations on the vehicle. Perhaps other sensor packages exist with the improvements in MEMS technology.

    Shaikh

  • avatar
    rexrcr

    Great discussion guys!

    Some recommendations for the curious:
    1. Google “critical damping”
    2. Check out OpimumG web site, better yet attend one of their webinars or live in person classes on vehicle dynamics. Money well spent.

    Also, many/most high-end luxury sport vehicles now have accelerometers attached to each hub, measuring spindle-to-body accelerations and then adjusting damping in near real time.


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