DanielB

I've seen discussions that say it's important to have the rear ride height be set higher than the front. A general rule of thumb seems to be 10 mm. The theory is that without enough rake, the car will push on exit from corners as the weight shifts to the rear and unloads the front. I guess the idea is that with an appropriate amount of rake, there is less weight shift rearward? Or is there some other principle at work?

I'm curious about how much rake those of you tracking your S2000s dial in. Mine is currently at zero rake. That wasn't intentional, but rather the way it landed up after everything settled. I can't lower the front without inducing rubbing and raising the rear means I need to pay to go to the alignment rack (I can do front in my garage but not rear easily). So before I begin spending to experiment, I thought I'd see what others are doing.

FYI, springs are 11k/11k so I don't expect there's a lot of vertical suspension movement in the rear on acceleration. Perhaps rake matters more with softer springs?

Chibo

It is a tool, like you said, does the car oversteer or understeer on exit under power?
I run negative rake by about 1/4".

DanielB

I think the car is mostly neutral right now. It understeers a bit in third gear higher speed corner exits and oversteers a bit in lower speed second gear corner exits. If I was going to make an adjustment, I would probably prefer a bit less understeer as the third gear exit limits how fast I can add throttle leading onto the long straight at the track I drive most. But it feels like I'm nit picking.

Does negative rake mean the rear is lower than the front?

noodels

Have 0 rake with FULL tank of fuel,
found that best for my drive,can feel the change to low fuel as would have a little rake then

Bruunz

The other thing to consider with rake is under braking.

The simple way i picture rake is take a chair then shorten or lengthen the front or rear legs - the chair becomes easier or harder to tip in a direction.

have a look at my thread here: https://www.s2ki.com/forums/s2000-br...-next-1171165/

Effectively all i change is tyre pressures and ride heights - last set of videos im at 0 rake.

robrob

My S2000 race car liked the rear end as low as possible (off the bump stops though) so I usually ran with zero rake.

miamirice

s2000Junky

Experiment. Too many variables to give a one size fits all answer. Generally a negative rake (rear lower) is going to have a bit more stability under high speed hard braking, but brake bias plays a part too ie pad selection and tire stagger. But for the sake of example, if the car feels a bit unsettle like the rear is squirming around on you a bit under hard braking, try lowering the rear. If the car just doesn't turn in as crisp and responsive as you would like without losing traction, lower the front to further weight it while lightening the rear. Generally you can influence under/over steer in other ways through driving style with throttle inputs and speed of the corner/down force available, sway bar weight etc, so generally a level S2k is a good place to start.

DavidNJ

Rake effects two factors: suspension geometry and aerodynamics. There is nothing magic. Unless significantly raising or lowering the CG it shouldn't affect weight transfer. If lowering causes the car to bottom, that is a different issue. The anti-roll bars may need to be reset to remove preload, bumpsteer may be affected, and alignment in general. All things that should be set intentionally and not coincidentally and need to be reset to a baseline condition. Part of the geometry changed can be to put the car in a different part of its camber change curve.

s2000Junky

Raising the center of gravity does effect weight transfer though. How many MM to perceive a handling change is debatable. You can see the rake adjustment reflected on a corner balance scale. We all know ride height effects wheel alignment/toe/camber change, so its assumed those are re calibrated with the rake/height change as a control measure for testing. I have gone back and forth over the years running an added 80lb up front with a supercharger or just NA, and I would generally go back and forth between a negative rake to help compensate for the added weight up front or normal/even ride height when running NA.