Chassis stiffness

[pentoman]

How stiff are MB's chassis' generally? It is always talked about at the launch of a new car these days - i.e. the new Passat is 35% stiffer than the old one etc. etc.

My 190e sometimes creaks, probably due to twisting, when I enter the driveway which is an odd, steep angled/twisted entrance on a corner. I assume this is because of a relative lack of stiffness.. Are the '80s chassis stiff; were they any good in their day? Anybody have any figures? Are they a lot worse than a new car because of the new techniques & technologies today?



I understand chassis stiffness is very important for ride & particularly handling, so that the suspension can work its stuff how it's designed too, rather than the body twisting & acting like a very bad spring and affecting the handling.


cheers

Russell

[Duke2.6]

High chassis stiffness is desireable, and overall chassis stiffness is usually expressed as the frequency of the first bending or torsional vibration mode, and 25 Hz is considered a good target. Mercedes have probably been stiffer than most cars up to at least the nineties, but the industry is catching up. The key is to increase stiffness without adding excess weight and this is possible with ever more sophisticated structural analysis software.

Back in the early nineties my car developed a creak in the right rear C-pillar, which was noticeable when the body was stressed in torsion like entering a driveway at an angle.

The dealer fixed the problem under warranty, but they never gave me an adequate explaination of what they did.

Duke