I wonder if someone can give some basic guidelines on how to setup a car for a rough track? Not necessarily Sebring, but perhaps Bridgehampton? Springs? softer or stiffer? shocks/damper? fast vs slow rebounds, front and rear....I'm looking for a starting point to better grasp what changes I should be making to control the car better.
Generally speaking, softer springs. That will generally mean softer (lower) damping. If you consider a bumpier surface to be lower grip on average, normal logic would suggest moving the rear a bit further to 'soft' than the front to retain some control. But obviously this is all very general advice.
It is simple - just make tires as hard as possible, reduce rideheights to the minimum, make stiffest possible springs and shocks, stiffest possible antiroll bars, use most possible amount of packers, use maximum downforce for biggest possible reaction forces from hitting bumps, use maximum amount of toe angles regardless negative or positive, use as little as possible caster for extra instability, and also make sure that tires are simulated to be as difficult as poissible so driving becomes really bold and difficult over any kind of instability as opposed to arcadishly simulated tires which literally makes everything that happens to car nearly meaningless.
Love how one simple question can get mantis a mental breakdown Anyways, fast bump lower seems to work very well. Slow bump (on Sebring for example) I still keep relatively high, due to the amount of quick turns.
Try reducing spring rate and increasing packers, I find this helps with rough tracks. The reduced spring rate absorbs the bumps and the increased packers reduces suspension travel so avoids the car bottoming out. This is usually the first thing I try.
Technically many of those things are true and untrue, because specific details are different. Speaking of tracks, Bridgehampton is more about damping sprung mass, Sebring is more about damping unsprung mass. Different undulation scales, different way and patterns of undulations and so on.... Not to mention simply layout and elevations. You just have to take the car, drive it, understand how it worked and if it could be adjusted to be better. Altering stiffness of a car will also alter its mechanical grip in turns, braking and accelerations. There is not that much to learn from generalizations. Although, I think Davehenrie created this more for discussion. Secondly, cars are very different... for example different, mass, different ground clearance, different aero, different speeds, different wheels and so on. What is stiff, or soft ? That also depends on each car and even a driver. Perhaps to me, a guy who loves more chassis motion a suspension rate that barely moves a car will appear as extra stiff, while other guy who loves hyper responsive car it will count as soft suspension rate. But hey this is simracing 2021, I guess we speak about latest GT3 cars then. Thats one interesting bit. IIRIC somewhere I saw the opposite being told. But iiric it depends on bump, but not sure... The thing which happens with softer spring is that unsprung mass falls more easily into a dip, while harder sprung wheel would instead fly over the dip. Thats not intuitive. Thinking about it a bit more, of course in turn, braking of acceleration it is more ideal to have wheel pressed firmly to surface as continuously as possible, but in terms of comfort at high speed in the straight it could turn out comfortable to have wheels flying over dips And dips, I'd say will always be more likely to form on the road than a bump. Bump and dip Aaaand, I think I learned it from this guy: Thats interesting, makes sense. However once packers are going to be hit, the force of the bump will transfer to the chassis, that is not great. Similar to bottoming out. Making suspension softer, and reducing the travel is of course making it more likely to happen. But I suppose if it doesn't happen, then it is good to go like that. I like older cars, I like how they has more practical, more true to public roads rideheights. It allows more suspension travel with greatly reduced possibility of bottoming out. Giving more comfort, grip and more show: I am not mantis, and it wasn't mental breakdown, it was humour.
The packers being made of a hard rubber type material or similar means it's a softer impact than the car bottoming out which also means the shocks may still has an effect which also means the tyres are having an effect on the rod instead of the bottom of the car. When I use to do Moto-X I tended to use a softer spring and then adjust the preload on the spring for the conditions of the track. I know fairly extreme suspension travel is involved with Moto-X but the overall idea is to keep the wheels in contact with the track.
