Originally Posted by EDWARD2003
why do manufacturers opt for flexible chassis design? What are your thoughts on this? Would this not have an effect on lateral load while in mid corner?
Could you explain "Jacking Effect", I assume this is another way of saying traction rolling or the precursor to traction rolling?
It's funny because I have been told that back in the 60s a lot of racers experimented with flexible chassis in full size racing. Now it seems full size race cars like a very stiff chassis, to allow the suspension to do its work. Keep in mind it is easier to adjust suspension pieces than the chassis stiffness in a full sized car.
For sure this is a very complicated subject and I have not done enough research to really do it justice. Having said that I will share what I think I know
First, all chassis will flex, so it is about controlling that flex to change the balance of your car.
In my experimenting here is what I found.
If I make the rear of the chassis more flexible, then the car has less steering and is more stable. Too much flex and the front inside tire wants to lift too easily, which can lead to traction rolling as well.
If I make the front of the chassis more flexible, then the rear inside tire can lift more again leading to a higher potential of traction roll. I honestly can't recall what my experiments on making the front more flexible did in terms of more or less front end grip. Thinking it through, I think it would make the car steer more, but I may be wrong on that...would need to test it again. Something is telling me I might had the opposite results, but I am really not sure. Your memory goes went you get to my age
Well from my research the theory behind a Jacking effect is that if your RC is above ground you will have some jacking. As the roll center gets higher, the more jacking effect you will have. Some people will define Jacking as the car wanting to "pole vault" over the (outside) tire contact patch while cornering, causing the inside tire to lift. This is why a low roll center helps prevent tracking rolling, because it is reducing the jacking effect.
By the way, the opposite of the Jacking Effect is referred to as the "Packing Effect". This happens when the roll center of your car is below ground. This allows the car to roll into the drive surface without jacking up the inside. Again this is why low roll centers are good at preventing traction rolling.
I also prefer the smoother feel the car has with a lower roll center...it is less edgy....but can be a bit too lazy and also can have the chassis rub the driving surface.