Ride quality, how do you quantify it?

[iscaboy]

I was talking to someone today (after having fixed the exhaust) about ride quality, the latest 300d, when coasting on the flat or downhill at 30mph feels like it is parked, even with the drivers window down, no noise, no vibration, no nothing, just waftiness.

The conversation started because this one is white, so far at least 50% of people who have seen it have said "wedding car", which is really what got me thinking.

give it a little bit of gas (I find 1,500 rpm more than enough for town work, keeps up with the traffic etc) and you get that muted crump-crump-crump of a straight six, but still no real noise, no vibration, put the window up and you can hear the dashboard clock ticking.

the last 300d wasn't as good, and the ride and handling definitely wasn't as good.

So I started to wonder, is there any way of actually measuring "ride quality" that can be applied by the average guy in the street, say the person I was talking to today?

I'm guessing a sound level meter from maplins, but better still record digitally and put it through a spectrum analyser.

But how about vibrations, clonks, shakes, (not that this car has any) and potholes and road paint?

I know that this 300d is better than the last one, I also think it is better than the C class a friend has, and the 123 another friend has (over the same roads) but how do you exclude my own personal prejudices?

nobody will argue with me when I say this 20 year old 300d drives and rides better than a 10 year old renault, but how about a 5 year old rover? Or (is this sacriledge?) have about a 10 year old S class?

I don't think MB arrived at the ride quality they did purely by accident, and I can't see the germans using nothing more than the subjective opinions of test drivers, or glasses of water stuck to the bonnet.

 

[Bobby Dazzler]

Ride & handling are difficult to measure because it's subjective.

The thing about ride – and handling – is that despite our ability to measure certain aspects of a car’s chassis behaviour, such as its grip, cornering speed and something weird called the circle of friction, it’s actually still a subjective matter when it comes to overall assessment.

Just because driver A likes the way a Citroen 2CV lists to one side through corners, while driver B prefers the more precise approach of a German sports saloon, doesn’t mean that either driver is right – or wrong – in their preference.

More: http://www.autocar.co.uk/blogs/anyt...andling-more-important-than-ride-discuss.aspx

 

[The Boss]

i think the ride quality is justified by the dampening effect through the shocks.

ie.. for a set amount of variance in the road quality, should reflect in a specific transmission of the variance of a %, the lower the % the better the quality, or the absorbtion of variance on the road.

ie what is happening outside is not felt inside.

further to this, there is then the thought of how the car returns to norm after enduring the road variance. ie does it return to normal, is it soft sprung, is it hard sprung, does it have adjustable dampeners etc..

sounds all over the place, but to me ride quality is based on me know a set section of road, either by bike or older car, and then to know that when i expect a disturbance due to road condition, and it is not noticed due to the way the car dealt with it, this is quality.

its no good a car acting like a water bed, nor is it to act like a rock, but its about absorbing the variance, and returning to norm, with out you noticing it basically lol



my God.. i think i need to sleep after that lol

 

[The Boss]

what about the Violin effect? resonance noise from the rear wheel arches when the e class came out in 1996/97, where the new shape of the rear arch led to a wining sound. To me, this would just ruin any quality measure! id go mad!

 

[grober]

Very few modern Mercedes with standard coil spring and telescopic dampers offer the superb ride offered by Mercedes in the late 80's early 90's. This is partly due the adoption of increasingly low profile tyres and harder sporting suspension. This improves handling to the detriment of ride quality IMHO. The characteristic failing of low profile tyres/ hard suspension is the transmission of low amplitude high frequency road noise at relatively slow speeds. Active/adjustable or air suspension on modern cars may be able to "dial this out" quite effectively by clever technology but they are starting from a position of disadvantage with their wheel tyre combination.

 

[The Boss]

Very few modern Mercedes with standard coil spring and telescopic dampers offer the superb ride offered by Mercedes in the late 80's early 90's. This is partly due the adoption of increasingly low profile tyres and harder sporting suspension. This improves handling to the detriment of ride quality IMHO. The characteristic failing of low profile tyres/ hard suspension is the transmission of low amplitude high frequency road noise at relatively slow speeds. Active/adjustable or air suspension on modern cars may be able to "dial this out" quite effectively by clever technology but they are starting from a position of disadvantage with their wheel tyre combination.

so so true.

the 126 and 124 had and still have wonderful suspension, very relaxing.

everything on the market today feels artificial.. its like you can feel the car working hard to correct road bumps.. before, you just coasted along relaxed and in harmony... and now..

 

[219]

Ride quality is defined by a whole list of parameters : springs , dampers , body mass , seats and , not least , tyres .

While I would agree that a W123 , W124 or W126 ( don't forget the W201 for which the modern multi-link rear suspension was developed at great expense , to endow a small car with big car ride quality ) are much better than the current offerings from most manufacturers , they are still 'boneshakers' compared to cars from 20 or 30 years earlier - have a ride in a Ponton , Adenauer , Daimler Limousine or RR Shadow 1 to see what I mean as they waft along on their 'baloon' tyres with a 'magic carpet' ride that completely isolates almost every bump in the road . Of course , these cars don't handle compared to modern cars but they are supremely pleasant to drive ( in the case of the two Mercs at least ) or be driven in . Sadly , some surviving examples of these cars have been spoiled by fitment of larger diameter wheels and lower profile tyres , thus greatly altering the original suspension design ( but I can sympathise as I know how difficult it can be to source , for example , 6.70x13 tyres these days ) .

 

[wemorgan]

AKAIK ride and handling has both subjective and objective assessments. The subjective parts are measured by an experienced test driver on a track and the objective parts measured using a kinematic an compliance test rig like this: Dynamic Kinematics and Compliance Test Rig.
Those factors are then assessed together with the noise, vibration and harness (NVH), which gives details about natural frequencies and cabin acoustics.
This all adds up to hundreds of graphs which the engineers have to interpret.

 

[grober]

AKAIK ride and handling has both subjective and objective assessments. The subjective parts are measured by an experienced test driver on a track and the objective parts measured using a kinematic an compliance test rig like this: Dynamic Kinematics and Compliance Test Rig.
Those factors are then assessed together with the noise, vibration and harness (NVH), which gives details about natural frequencies and cabin acoustics.
This all adds up to hundreds of graphs which the engineers have to interpret.

This technology could form the basis of a comparative study of say Mercedes early 90s suspension+tyre philosophy/design and the current suspension+tyre offerings---- any motoring mags listening??

 

[Bellow]

This technology could form the basis of a comparative study of say Mercedes early 90s suspension+tyre philosophy/design and the current suspension+tyre offerings---- any motoring mags listening??

If you are capable of solving second order differential equations!!!

For the OP, a lot of what you are talking about is as Wemorgan says, NVH.

For the dynamics of ride and handling, have a look into spring frequencies as they appear at the wheel, the ratio of them front to rear, and the influence of the antiroll bars. That's the basis of ride quality.

 

[Stratman]

My 2004 C-Class on 15" wheels and doughnut tyres is very pleasant.

I've never been a fan of 'rubber band' tyres. I prefer my teeth and spine in the location nature decided they should be.