Why are Modern road cars set up so stiff

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Smokes
Smokes
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Joined: 30 Mar 2010, 17:47

Why are Modern road cars set up so stiff

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I have recently driven a lot of modern road cars nothing sporty, one thing annoys me is they are set way too stiff, so every bump (incuding the road undualations created by the road rollers) get fed into the chassis and not into the dampers.Causing the car to crash and rattle over every little bump If the chassis is getting the bump force then tyre is losing contact with the road as it is not following in the contour of the road. I usually feel a at high road speeds the wheels being kicked into the air and then crashing back into the ground. It is very irritating and not good for a to b driving on modern roads.

Why have all manufacturers forgotten the basics that the mark1 focus did so well in terms of ride and handling?
It was a case of decent bushing selection damper and spring rate rates and stiff roll bars. the blade suspenion was just marketing speak for a trailing arm rear susoension with an couple of tweaks. =Smooth easy to drive car for every day a to b diving use.

The elise also has a relativly soft setup which makes the ride smooth but is still quick on the track. How did they do this?

I know that peugeot were the world leader in OEM dampers design; They used to use 4 valve progressive damper internal droop spring. But went to bilsteins as there own dampers were too expensive to manufacture.Yet they manage to get thecar to ride and handle decently on bilsteins how?

Also top gear tested a golf in it three Magna ride setting and found that the comfort mode was the fastest setting around the track.

I don't feel that having a stiff supension is neccessary for road tyres they are not sticky enough to genrate the skid pan g forces that require such a stiff suspension. And thus think it would more comfortable and safer to reduce the spring and damper rates to allow the tyre to roll over the bumps rather than crash over them. This also means that the tyre will not lose contact with the road surface.

Therefore: is the stiff suspension requirement driven by the marketers who say that the need make the car feel sporty by having a stiff suspension setup? In order to sell it to the market?

Lycoming
Lycoming
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Joined: 25 Aug 2011, 22:58

Re: Why are Modern road cars are setup so stiff

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Did the manufacturer claim the car was tested at the Nurburgring?

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Holm86
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Joined: 10 Feb 2010, 03:37
Location: Copenhagen, Denmark

Re: Why are Modern road cars are setup so stiff

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Could Run Flat Tires have anything to do with this?

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flynfrog
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Joined: 23 Mar 2006, 22:31

Re: Why are Modern road cars are setup so stiff

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Holm86 wrote:Could Run Flat Tires have anything to do with this?
also newer lower profile tires give a much worse ride. It would be helpful to know what cars the TS is talking about.

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Ray
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Joined: 22 Nov 2006, 06:33
Location: Atlanta

Re: Why are Modern road cars are setup so stiff

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I run 45 series tires on my lowered truck, and while I love the way it looks, I HATE the ride. That's the price you pay I guess. Another huge issue is the fact that roads here in the US aren't built correctly when they were laid down, they aren't repaired correctly, and they are very rarely repaired. I understand that car dampers and tires can only do so much, but the root of the problem is our absolutely terrible roads and there's no indication that any real maintenance will ever be done on them.

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Tim.Wright
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Re: Why are Modern road cars are setup so stiff

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I'd agree that a lot of it has to do with the trend towards massive wheels. Nobody are interested in buying a car with 13" or 14" wheels anymore and they are paying for it in ride quality.
Not the engineer at Force India

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Ray
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Joined: 22 Nov 2006, 06:33
Location: Atlanta

Re: Why are Modern road cars are setup so stiff

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I have no doubt that suspensions could be properly designed to work with just about any wheel and tire combo, but the roads have to not be utter crap. And around here, they are. Hell, in a county not too far from me they are spending $500 MILLION+ on a new baseball stadium while their county education system has a $50 million deficit. Baseball is more important, so that's why their kids will have a potentially worse education and on top of that their roads are garbage.

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Tim.Wright
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Re: Why are Modern road cars are setup so stiff

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Ray wrote:I have no doubt that suspensions could be properly designed to work with just about any wheel and tire combo, but the roads have to not be utter crap.
Roads are what they are. You need to design the suspension to the road, not the other way around.

If you want an acceptable ride, you need to tune the suspension for that and the suspension includes the tyres. If you have very stiff tyres, there is an upper limit to what you can acheive in terms of ride before you start sacrificing handling.
Not the engineer at Force India

marcush.
marcush.
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Joined: 09 Mar 2004, 16:55

Re: Why are Modern road cars are setup so stiff

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I can only underwrite the thread starters point.
Make no bones about it ,cars are getting heavier all the time -so controlling the masses is more of a focus these days and those tyres with low shoulders combined with heavy unsprung weight does not exactly help the damping either.
combine this with insane cost targets for components and you end up with crappy damper hardware not up to the job - not even Porsche allows themeselves to spend into ohlins type of hardware and the result is crappy ride .
when I started to work on a project at Weissach regularily driving Carreras I was rather shocked and disappointed with the ride quality available ,especially with the background of development activity with Lotus Elise/Opel Speedsters for Ohlins ..

I´d contest the statement of the setup being stiff -it´s more a matter of unresponsiveness and judder tendencies.
One thing you have to take in is the tendency to throw Mcpherson type hardware on all cars these days ...it´s just a costdriven thing but certainly not much help when it comes to ridequality.
Just try to squash a even lightly sprung Mcpherson car down and you see it´s hard like a rock when not moving -as the geometry instantly goes into bind -combine this with cheap bearings and you got a system that improves only with speed .

you need dampers who do not rely on travel to build force..The TTX at that time was instantly producing force a half milimeter of travel was enough to get it to work ....compared to a conventional damper which needs travel in the range of centimeters to build up full force ...mind you ,that´s not only a delay in damping but also a looong period of time to allow the wheels or car body to do things out of your control....eg...ride quality is sufferring.

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SectorOne
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Re: Why are Modern road cars are setup so stiff

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Smokes wrote:Therefore: is the stiff suspension requirement driven by the marketers who say that the need make the car feel sporty by having a stiff suspension setup? In order to sell it to the market?
Yes it´s a gimmick. Sport mode and all that stuff is superficial feelings rather then actually making the car quicker.

A system that actually works is like the Mclaren P1 where it drops the car 50mm and properly sets the car up for track use.
But the sport button in your average BMW is just to get a sporty feel.
"If the only thing keeping a person decent is the expectation of divine reward, then brother that person is a piece of sh*t"

Smokes
Smokes
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Joined: 30 Mar 2010, 17:47

Re: Why are Modern road cars are setup so stiff

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one thing I noticed when I worked in the automotive industry was that the marketers listened to the customer demands of bigger wheels and lower profiles tyre and a sporty ride.
So i guess the engineers gave the customers exactly what they wanted. Which why most cars apart from the fords and peugeots and Jaguars have this harsh ride. Unfortunatly Jaguar are starting to move away from the magic carpet ride toward this harsh crashy ride according to some test reviews. I last rode in a xkr supercharged vesrion. Bentley also have this crashy ride as well but it is more to do with the airsprings limitations more than anything else.

Unless you are going to run bigger diameter brakes you should try and keep the wheels small as alloy wheel .
As the alloys are cast are and end up quite heavy in comparision to a steel or forged wheel as the material used is a cheap low grade and not paticularly strong alloy to keep costs down.
Also having a tall side wall helps the ride alot as the sidewalls allow enough flex over the small bumps and stops some of the bone shaker ride you get with low profiles a low speed.
You can argue that taller sidewalls are not good for fast high speed cornering but the counter point of this argument would the majority of customers would not want to achieve the high speed cornering and those that do would propbably want to run track orientated tyres and tune the setup for track use.
Having said I have driven an old group 5 citroen AX gti stock hatch on pubics road which rode really well and was a hoot to drive this used high 65 profile tyres on 14" rims and tarmac spec peugeot rally suspension.

Jersey Tom
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Re: Why are Modern road cars are setup so stiff

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Smokes wrote:one thing I noticed when I worked in the automotive industry was that the marketers listened to the customer demands of bigger wheels and lower profiles tyre and a sporty ride.
So i guess the engineers gave the customers exactly what they wanted.
I'd rephrase it to say... the engineers deliver what the marketers want, and the marketers want whatever they can sell the customer. But yes, the customer (particularly those with disposable income) think that big wheels and slim sidewalls and stiff springs are good.. so they'll pay for them.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

Greg Locock
Greg Locock
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Joined: 30 Jun 2012, 00:48

Re: Why are Modern road cars are setup so stiff

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I think one of the trends that is being ignored is the one towards better handling.

UK car magazines worshipped BMW for so long that everybody in Europe moved towards better handling, at the expense of ride. For a given architecture the two are more or less direct tradeoffs, if you want better ride and the same handling, or vice versa, you can't tune it with springs sta bars and shocks and bushes (assuming the original setup was competent), you have to change something more significant (most easily and most expensively the tires).

This is, of course, crazy. Most people drive so far within the limits of the car most of the time that all they get from that compromise is rattly cars and bent wheel rims, the positives from the improved handling are rarely experienced. OK, I do think that a modern car is a better one to avoid an accident in, it'd be interesting to see data on whether real people do actually drive themselves out of danger using 0.8g, or if they just point the car in the right direction and brake very hard. I suspect the latter.

marcush.
marcush.
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Joined: 09 Mar 2004, 16:55

Re: Why are Modern road cars are setup so stiff

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complete and utter nonsense manufacturers following the demands of magazines...this is the other ways round.Media are tools for the manufacturers to sell the product and OEMs use the tool extensively.
It´s a myth that customers demand this and that -if it were not available nobody would bother..a very good example actually is the ride ....no need to make a car feel so stiff and harsh.Nobody would ask actively for that behaviour...but general consensus is a stiff and harsh feeling car is sporty..why ? In general nobody has the slightest idea of grip and limits of adhesion ,so who would care about the minimal improvements to be had by going for a setup wich comprmises ride.
mags do write their stories exactly knowing who is bankrolling their job.look inside the mag and you see the big advertisements of Porsche for example.You can expect the OEMs not forgetting to park one of the current must haves in the magazines garage -dliberately forgetting to collect it after the test for at least some time...so isn´t it a convenient thing to have the journo demand a firm ride and save a lot of money not having to fork out a lot of recources to get a proper damper ?
Then a general consensus is reached that this is what is the right thing and presto we all drive impossible rattleboxes and call it state of the art...

Greg Locock
Greg Locock
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Joined: 30 Jun 2012, 00:48

Re: Why are Modern road cars are setup so stiff

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Are you saying that manufacturers don't chase car magazines opinions, or that they shouldn't?

Beacuse (a) they definitely do at least in some cases and (b) yes I agree they should know better.