I Wanna Know - Modern Suspensions

[dereklola]

Over the years suspension design (on typical race cars as we know them) has changed significantly. What caused this?

For instance 30/40 years ago the length of the upper control arm was maybe 60-65% of the length of the lower arm, and at a more inclined angle. All to control the outer wheel camber as the car roll angle increased when cornering. Over the last decade or more control arms have become longer and almost equal (upper arms about 90% of lower) and little difference in angle. Of course car width (track) has increased too, limiting roll angles.

Is this because stiffer springs (for aero reasons) limit roll angles and thus less camber compensation is needed? Or is the effect of different control arm lengths hidden by the stiffer springs and therefore no longer critical?

Just wondering what other people's opinions (or better still analyses) are.

Personal reference - I changed my vintage 1976 Atlantic to a more modern 1991 F3000 - which clearly illustrates the above phenomena - but both seemed equally qualified to "do their job". The chassis (and driver) roll may have changed but the relationship of tire to CG of the car not so much. Although maybe if I changed back to the vintage Atlantic now I'd notice a difference. Or is the difference only really noticeable by drivers nearer the limit than I am - in pro and senior amateur racing?

Just wondering.

[aims20]

Tires have become much less camber sensitive mostly. By having less inclination difference between the upper and lower arms, the Instantaneous centers move much much less - which means less jacking effects on the chassis through ride/roll movements and a much more stable aero platform.

That's my guess.

[Charles Warner]

Chassis flex - in both car and driver.