Disagree. How can you discount a force acting upon the car except when it's conveniently disregarded for argumentative purposes?BillyShope wrote:Similarly, ring and pinion forces need not be considered.
The rear end housing is not "merely" a giant link. It is a unit used for the transference of power and therefore has dynamics acting through it and therefore transferring those forces through which it is attached. You know, that pesky Newton's Law of Physics thing? Once again, you have disregarded bar angles and spreads. For all the effort you put into your webpage, I don't know why this basic aspect is ignored.BillyShope wrote:The rear axle assembly can then be considered as merely a giant link, with pivots at the tire patch and at the front pivot. A moment cannot be generated at either of these two points, so the line of action of any force acting at one of the two pivots must pass through the other pivot.
Wow, with that statement you just blew the minds of thousands of chassis builders and racers. A ladder bar and 4-link I/C DO NOT act the same. If this is your belief, we will not reach any middle ground. A ladder bar has different force vectors than a 4-link since it is one unitized structure whereas the 4-link is obviously not. Ladder bar cars would be much easier and cheaper to build but, rarely are these days. Why is that? Rhetorical question...........BillyShope wrote:But, this has been a ladder bar car and not a 4link. The instant center of a 4link, however, acts in exactly the same manner as the pivot of a ladder bar car.
I'm almost speechless if you think the only force enacted on the car is the through the I/C. The rear end housing wants to rotate in the opposite direction of the tires and therefore transmits that force through the suspension links. If you choose to discount the different leverage forces created by the possible different attachment points, I'm at a loss for words. Billy, would you agree that the desire of the rear end housing to rotate pulls on the upper suspension links and therefore pushes on the lower suspension links? If you can agree with that, surely you must consider the leverage ratios of bar spreads and bar angles acting upon the chassis attachment points.BillyShope wrote: The body under consideration has no "idea" of 4link spread, bottom link angle, or anything other than the force it "feels" acting at the instant center.
I was never describing the "suspension" of a pencil, I was describing the force acting through a suspension link and using the simple example of pushing a pencil and how it reacts to the force moving it.BillyShope wrote:Remember that a force can be moved anywhere along its line of action. You can balance a pencil on your finger or you can tie a string around its balance point and suspend it. Same force and same result. Only the point of application has been changed.
Once again, angles of force vectors are being discounted. I just don't know how you can disregard the laws of physics.BillyShope wrote:Similarly, that force acting at the instant center can be moved anywhere along its line of action. Remember, now, that "line of action" is the same as a line of constant percent antisquat.
Nope. It is ONE factor of many that define the dynamics acting upon the car's ability to launch. Let's find that 3000 HP Pro Mod car that has the I/C on 100% anti-squat (doubt we find one but....) and make a pass. Then, let's stiffen the springs up so the ride height remains the same and throw 100# in the rear and make another pass. Since the I/C didn't change, the results of the launch should be the same, correct?BillyShope wrote:It follows, then, that the percent antisquat is the defining factor in the determination of a car's dynamic performance during launch.
Guess our definitions of "roll steer" aren't the same. You're talking chassis roll or "roll rotation" and I'm using it as the common used term to describe the thrust of the rear end housing acting upon the chassis points which induces non-driver forces to steer the car.BillyShope wrote:Roll steer effects occur when, as a result of chassis roll, the entire rear axle assembly rotates in plan view, causing a steering effect akin to the push karts you might have built as a boy. Anecdotal consequences, such as have been supplied, emphasize the importance of the elimination of that chassis roll which occurs as a result of driveshaft torque. An ARB helps, but complete elimination of chassis roll can only be achieved with some form of suspension asymmetry which cancels the driveshaft torque effect.
Billy, I respect your accomplishments and your history. I'm sure you've got some great tales to tell. You're indeed a man who has ascertained a large amount of knowledge and are willing to share what you believe is correct. I am ready to stop my contributions to this on-line debate since you continue to discount the basic findings of many other well-respected "experts" of this subject. Are all of my points of discussion my own findings? Hell no they aren't. I read what I can on the subject and discuss with others to sort through what really applies and disregard what doesn't. Your context disputes many who are considered "experts" in this subject area who have had much success. I am not totally discounting your asymmetrical 4-link setting under the right application but, to continually state bar angles and spreads aren't a factor when they indeed are, will not buy you much time at the microphone.
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