I haven’t seen a good thread here about this and I’m going to need to start playing with all of these when I get my car back on the road finally.
I’m hoping some of the guys who have a lot of track experience can chime in and give their recommendations for the street, for the track and maybe even a sweet spot that could be used for both. (Sasha, Andrew, Adam, TM, etc)
I almost feel like I should be asking on a miata board or something - most people I talk to don’t seem to give 2 shits about this stuff they just run whatever their friend told them their heard they should run.
For what it’s worth, I’ve found that up until about -1.7 degrees of camber, there’s not a great increase in inside tire wear from normal street driving. Front toe I keep just less than 0, like -0.2
I keep my fronts around there and the rears at -1.3-1.5. As for toe, you may want a little more, like -0.5 toe in for stability.
I don’t mess with caster.
Not that I’m an expert or anything, it’s just what I’ve found I like!
caster is simple to understand but often hard to get right…
consider the standard mac strut + tension rod… they both have a swing, when they are level they are the longest, anything above or below level the shortest…
so assuming you want negative camber in a turn at all times no matter the dive, the tension rod (assuming it’s in front and not behind the control arm) would have to start level at full droop and swing up and forward pulling the control arm (hence the need for bushings)
if you corner hard and the nose doesn’t dive because you have big swaybars and stiff springs, then your caster won’t affect you much, and you’ll have to get stickier tires and load up the front with a weight transition when in the turn to use the caster (sometimes this means tapping or lightly riding the breaks mid-turn, or tapping the gas in a fwd car)
the whole point is that because the normal “soft” car tilts so much in a turn that you need the extra caster angle to maintain negative camber, without it you’ll be rolling over your sidewall and chewing the outer edge of the outer tire (problem on my k-car boohoo)
how this affects the inside tire can vary, again it depends on the compression of the spring and where the tension rod is level… if the tension rod is below level at full droop (and level when the car is sitting) you could start to go positive a touch on the inside wheel and drag it in the corner, which slows you down and again chews the tire… but the dragging can help stability in that it acts much like driving into a puddle of water slowing your inside a touch
remember that having a car tilt/roll in a corner is not necessarily a bad thing, the loading/twisting actually helps you grip by moving some of the lateral force into the chassis and away from the tire, and the opposite is tru for race cars that don’t roll, you transfer more force into the tire, so you need better tires and there’s a very small “warning” threshold before you lose grip altogether… and a side effect is that a softer car will need less negative camber than a stiffer one for the same loading of the tire’s contact patch
reading it again… I think I was going to say something about the grip, with the same tire you’re less likely to break loose with softer springs/swaybars, but somehow came out wrong
I think it’s important for any driver to understand how the geometry changes work, and learn to feel it, so you can at least diagnose where the problem is even if you don’t know exactly how to fix it… you can always guess and test
