Caster

[Mr.Kennedy777]

Has anyone messed with taking a bunch of caster out of RF, (even negative) but using combination of tire size, offset spindles, spindle drop and KPI/scrub to keep some feedback in the wheel? Just been thinking lately about how caster settings have traditionally been used with vehicles that track straight ahead with the wheels straight, not turned to the right to go straight. Maybe I'm way out to lunch here but it would make sense from a contact patch and equilibrium standpoint to kinda keep that tire as stable as possible wouldn't it? Or to even gain negative camber during counter steer some and slightly jack weigh to LR when you unwind coming out. Negative caster is darty but that's only if you don't address the trail (which you could use an offset fore/aft spindle to make more self aligning torque). You can get the same amount of caster trail (or lead however you wanna call it).. with different caster settings using your spindle drop, tire size, and offset front to back. So you can keep the feedback force in the wheel even with lower caster values. Just wondering if anyone has been doing anything like this?? Any ideas? Thanks in advance.

[MasterSbilt_Racer]

Has anyone messed with taking a bunch of caster out of RF, (even negative) but using combination of tire size, offset spindles, spindle drop and KPI/scrub to keep some feedback in the wheel? Just been thinking lately about how caster settings have traditionally been used with vehicles that track straight ahead with the wheels straight, not turned to the right to go straight. Maybe I'm way out to lunch here but it would make sense from a contact patch and equilibrium standpoint to kinda keep that tire as stable as possible wouldn't it? Or to even gain negative camber during counter steer some and slightly jack weigh to LR when you unwind coming out. Negative caster is darty but that's only if you don't address the trail (which you could use an offset fore/aft spindle to make more self aligning torque). You can get the same amount of caster trail (or lead however you wanna call it).. with different caster settings using your spindle drop, tire size, and offset front to back. So you can keep the feedback force in the wheel even with lower caster values. Just wondering if anyone has been doing anything like this?? Any ideas? Thanks in advance.

When weight transfer and antisquat have already shifted weight to the LR, and the car is headed "straight", why would additional LR load be required?

[Mr.Kennedy777]

I guess a better way to ask that question Masters is why would you want to unload the LR when you unwind?

[Mr.Kennedy777]

Would it not make sense to have the mechanism that drives the RF provide optimum stability and offer the wedge increases and decreases that were beneficial to higher corner speeds and exits? By nature the negative caster RF deal would already be loading the RR a little more in the corner when counter steered compared to a traditional setting, and on exit it would be able to help maybe not so much add load, but keep load there on the LR to stabilize the RR better as well. Remember we haven't eliminated spindle inclination so even with a small negative caster value there is still some jacking going on.

[Mr.Kennedy777]

If you offset the spindle so the ball joints were ahead of contact patch you could achieve a negative caster with a positive trail, meaning it would still create a self centering affect.

[Jking24]

Maybe your theory is way over my head here but what would be the perceived advantage to this

[Mr.Kennedy777]

Stability of the contact patch. (0.2° from full right to full left during end to end steering)Reduction in jacking forces that cause the RF to rise up and down mechanically from steering input. (Allowing a more natural roll tendency during cornering with wheels counter steered and more natural weight transfer motion when the wheels unwind as much)Dynamic wedge changes from steering input other than caster could help achieve the same thing that caster does when it has a positive setting.. Another thing I'd have to test is that having a reverse caster split might want to make the front end naturally track to the right, which means less steering input to the right might be needed in the corner, which is a good thing since in order to make more front grip, you need the front tires to have a bit better angle of attack into the corner to gather more of the lateral force and roll out the contact patch offering better resistance to sliding up the track. Not saying the wheels should be pointed all the way to the left, but having them less right/more into the turn radius would actually improve RF cut through the turn. This would reduce the overall demand on RR to resist sliding, and might even take some load off of it, in turn opening up the ability to achieve a higher speed to get the RR back to its, "sticking point" so to speak.

[Austin34471]

Whats worse? The jacking and camber conditions caused by 5 degrees of castor (which is small compared to other forms of automobiles), or having to add scrub radius, caster trail, and maybe have to deal with the driver not knowing where the front tires are as well. Even if it is better from a grip standpoint, (which I am not conceding), if the driver isn't as comfortable, it may not lead to better lap times.

[Mr.Kennedy777]

The feedback you get from your tires comes from your lead not the caster itself. You can give yourself the same feedback in your wheel with 5 degrees of caster as 10 by adjusting your lead by moving ball joints back on spindle when you go to 10. It's when you move them back you should add scrub for counter steer. When the tire experiences a lateral force the sprung mass feeds a force into the spindle. The lower being closer to spindle center will exert more force. This causes the self centering and feedback that tells you wheel position. So I know for fact you would know where the tire was pointed. And LF would remain positive so there's that. In terms of scrub I was thinking reducing it significantly. Just based on the path the RF follows with ball joint lead on hub. In counter steer with smaller scrub it would follow very similar path and end up in the same spot as a regular spindle with larger scrub and no lead. Also with slighter more inclination to help reduce scrub radius, there is still jacking from your spindle inclination. All of your bump steer changes could be stabilized by anti dive and moving rear upper a arm pivot ahead and the front upper a arm pivot much further ahead. The shorter rear pivot controls camber, while the longer front controls caster gain. The longer side view swing arm stabilizes the anti dive change during LR hike. I've been kinda playing around on an analyzer and it really appears to be a really stable design. Little more toe is needed as well. But it has good mc migration, especially in dynamic attitude it really only moves up and down with chassis movements.