The man wants MORE caster. How about this idea?
I just love the way Blu does that, I open a door, he bursts right in and fills the void with his tech and minutiae, then leaves supporting my point.
Big caster causes heavy steering in traffic and parking lots, which may be challenging for small folks who aren't expecting it .
You don't need a ton of caster to get directional stabilty .
Thnx Blu
LOL. First, I really didn't support your point.
And you're still speaking in generalities, with no
quantitative information given at all. What's "a ton" of caster, or "big" caster? Is that +5° you're talking about? or +10°?
Absurd is running less than +3° on the street with radial tires, even skinny ones.
Yes, you can have "too much" positive caster. That's really obvious if you know what caster actually does.
Like almost EVERYTHING suspension related, how much caster you need/will want depends on how your car is set up and how you're using it.
The +6.5° I run on my Duster isn't too much. I've run my Duster with 275's up front with everything from about +3.5° of caster all the way up to +8° of caster, and +6.5° is great, even with my 16:1 steering. I suspect you're trying to suggest that's too much, but that's wrongheaded. Of course parking lot speeds mean heavy steering, but most people would consider a 16:1 manual steering box with ANY amount of caster "heavy" at parking lot speeds. With the way my car is set up, once you start dropping below about +6° of caster the tracking effect from the wide front tires starts to become noticeable. And really after you drop below around +5° or so even the reduction in steering effort from dropping more caster is less noticeable too. Above about +7° and the steering effort starts increasing exponentially, and the "jacking" effect you get from turning the wheels becomes more noticeable.
But it depends on your set up,
@BergmanAutoCraft was running his Dart with +7.5° of caster the last I saw him post his specs. But he's running Borgeson power steering, so the added effort isn't an issue.
Hotchkis or QA1 all inclusive kits - which one?
And I've had no issues with tire wear, breakage, etc. running +6.5° of caster. Even running -1° of camber, which is more of a tire wearing setting anyway.
The thing about the SKOSH chart is you have to remember is how old it is- it's well over 30 years old. It's basically a guide for the kind of all season radials that are popular on 15" rims, and the 15" rim itself is pretty limiting on how wide a tire you can run. The other thing is that offset UCA bushings with stock UCA's were really all most people had access to when the SKOSH came out, so getting more than +4° of caster wasn't easy to do. And even the SKOSH recommended more caster for the FMJ cars, and some of us run FMJ spindles for their additional camber gain.
With adjustable UCA's out there, and 18" rims that allow you to run 275's up front with soft, high performance tires, the SKOSH chart is pretty conservative for positive caster. I wouldn't run less than +5° if I was going to run 255 or wider front tires on the street, and that's more than the SKOSH recommends for track/autoX use.
Most modern high performance cars run +9° of caster or more, that's the spec for an SRT Challenger for example. But they're all power steering.
Still, for more modern tires I'd add +1.5° of caster to every category on the SKOSH chart, even for manual steering.