tuohon on pakattu koko antkristus ilmiö hyvin.................
Okay, this seems to be a reoccurring argument on this board, so, fully expecting a newbie flame, I’m going to throw in my $0.02… The whole argument that you are getting less traction when you have anti-squat is absurd. What anti-squat does is translate the torque reaction on the axle into a vertical force. What will happen when you have a properly designed suspension is that as you accelerate, you drive the rear axle into the ground to find more traction. You made the statement: “the axle can only "push into the ground" with as much force as the physical weight of the rig on top of it” When you run zero anti-squat the body just leans back, and some force that could have been used to push the rear tires down is now going into compressing the shocks… To use an easier to quantify example… do you have any experience with drag cars? It’s very educational to see just how dramatic of an effect you get from playing with the anti-squat characteristics of the rear suspension, and the results are very obvious because you can see them in your sixty foot times… I have seen the same car run with very little anti squat just sit and spin off the line add some anti squat and dead hook using the exact same launch technique. Granted, this is very different from the varied terrain we experience off road, but the information is still applicable…
There is such a thing as too much anti-squat obviously. Everyone knows that the scorpion has WAY too much… and we all know what weird habits it has as a result of this… but to say that you shouldn’t have any is akin to stating that if you lift your truck too high it becomes unstable on side hills so we should all lower our trucks instead of lifting them. It’s just absurd. As with everything else there are compromises. Anti Squat is GOOD. This is a fact… what is up for debate is just how much one should have. Before answering this you must identify the specific problems with too much anti-squat, you must identify when these problems occur, and you must understand why those problems exist.
First, I’ve heard people state that anti-squat will cause the rear suspension to crawl under the body… Not entirely true... What is usually happening in this situation is that people are running too much travel for the length of their links. On full droop the angle of the links get to such a steep angle that the amount of anti-squat you are running now becomes relatively huge. To say this happened because your suspension is set up with anti-squat is ridiculous… It’s because the suspension links are running at overly steep angles and/or you are trying to get more droop out of the suspension than you really practically should… I usually refer to this as effective or ineffective travel… it is why a lot of ramp queens suck on the trail. If your axle is still on the ground, it doesn’t do you any good if it cannot physically push the truck forward because the control arm angle has become too steep. So that is the issue we are dealing with there.
Another common anti- anti-squat argument is that anti-squat causes the suspension to act like you are experiencing axle-wrap because the truck will hop. While the hopping description is true, the reasoning is completely different. Axle wrap has the leaf springs twist due to an inability to keep the axle from rotating, the hopping occurs as the energy that has gone into twisting the leaf springs is released, causing the suspension to hop. There is very little positive to this, for the most part, it just makes getting traction difficult and it breaks things. The hopping that occurs from anti-squat is a little different. What is happening is that the vertical force on the rear axle is proportional to the amount of torque being transmitted through the axle. Using the whole opposite-equal theory, the amount of torque actually being applied is proportional to how much traction you find. Essentially what is happening is as the suspension gains some traction; it uses some of that force to push down on the axle to help get more traction. When you are working on the varied terrain that we run on, the traction from one spot is different from a few inches away from it, so when working at the limits of traction, the suspension starts hopping.. finds traction, pushes down on axle, loses traction, force goes away, body comes back down again. This is a clear example of something that would happen as a result of having too much anti-squat. One solution people have come up with is the tight limiting strap. What this does is that you can now run a lot of anti-squat, and this strap, and on climbs, you stiffen up the rear suspension dramatically, but the strap prevents the truck from actually rising. Now since the rear of the truck can’t lift too high, you are preventing a lot of the up and down motion… The hopping is still somewhat present, but is so little that you really don’t notice it. While some may look at this as a band-aid... It actually doesn’t necessarily have to be viewed as that. You are still taking advantage of the stiffening of the rear suspension that anti-squat provides, which helps put weight on the rear tires… Technically speaking, I would view a suspension that needed a limiting strap to keep it down as having too much anti-squat... But there definitely is something to be said for running it this way… It brings along enough advantages that it might be the best way to go. Once again, as I had said before, anti-squat is a GOOD thing, what is up for debate is just how much is best…This is where that debate should be. I realize that is where the subject of this thread is, but there still seem to be people arguing that you don’t want any anti-squat, that is what I am directing this towards.
One last quick point… I noticed someone say “the only thing that I think would suck is that that same anti-squat that MIGHT help ya on the climp, could screw ya on the down hill.” You have to remember; the torque reactions on the axles are the opposite when you are slowing down… such as when you are going down hill… so that same force that was pushing the axle down on a climb is now pulling it up on a downhill… While that sounds good, it actually can be just as devastating. This is what causes brake hop on cars with too much rear anti-squat. If you look at a three link on the rear of a Trans-Am car (probably the pinnacle of solid rear axle suspension design) they use a 3-link rear suspension with a short upper and very long lowers. What this does is that on braking, the rear end rises a bit, and the control arm angles become close to each other pulling out the anti squat, but on acceleration, the more the rear suspension compresses, the more anti-squat the suspension has, and the more traction the rear tires now have. It works very well and makes for some fun tuning possibilities.
I really think that people who feel you should run no anti-squat are really missing the boat. Anti-squat is a good thing, but as with anything else, you have to understand it to utilize it. You won’t have any tragic effects if you have no anti-squat, but you are leaving traction on the table, and on those climbs that you *almost* made it… had you properly designed the suspension with a little anti-squat… it could have made the difference. On the other hand, if you put in way too much anti-squat like the scorpion has, you might end up with problems that could render your truck undriveable. (The scorpion retained most of its driveability through a creative spring arrangement… hell, the scorpion got its name because it had so much anti-squat that when it first was driven… before the spring trick… the rear end would shoot to the sky on launch… kinda like a scorpion). In closing, you definitely want anti-squat, it definitely will give you traction. If you don’t agree with this, then you should tell every other motorsport that uses solid axle suspensions that they are screwed up because while every motorsport uses different designs to accomplish different goals, they all have one thing in common, and that is that they use anti-squat to maximize the amount of traction that they get. In fact, this is the one of the biggest things you gain from a solid axle suspension over independent suspension. You can use this torque reaction to your advantage… I say USE IT.
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