4 link design, anti-squat question

Edited: 12/11/2008 8:30:22 AM by msturg

As far as mini's are concerned is there a preference to how much anti-squat to build into the rear suspension?

I'm currently designing my rear tri-four link and trying to keep the upper bars pretty low. With my design I'm right at 100% anti-squat. With a mini, that isn't exactly pushing a lot of power does this effect it good or bad?

While I'm at it do you have any opinion on centering rear differentials? If it came factory offset is there any cons to centering it? I'm sure the factory did it for a reason, not because it was convenient to offset

Actually I answered my own question after thinking about it. Like an idiot I was setting it up damn near like a race car, which meant I was getting a ton of pinion angle change with pivot points in the same plane. I was focusing too much on trying to keep everything low as possible.

I know you recommend the instant center to be near the bumper/grille/engine area, question then is do you really have any anti-squat at all? If no, is it something that can be helped?

I really want the truck to ride soft but not like a boat. I know a lot of this can be helped with shock location as well and quality of shock but I don't want the suspension to hinder this.

Also, I currently am in a strange predicament. I need a ton of lift in the rear of an SUV in order to untuck a 28" wheel and tire combo. However I only need this lift in order to make it easier to remove the wheels. I almost always drive in a cali position and don't have many issues.

I keep trying to write something but it doesn't come out correctly. Lets just put it this way, is it worth sacrificing pinion angle change (of course only to some degree) so that I can run my upper link bar front pivots closer to the ground and get better handling?

I have no intentions on racing this vehicle what so ever but I also don't want to take every turn at 20 miles an hour and everytime I punch the gas have the back end of the truck slam down. Maybe I am just going over board with what I think might happen.

sorry for the novel

so, what is the change in pinion on your normal everyday range of motion? I wouldn't be to concerned about extreme pinion changes when the truck is all the way up to untuck the tire. I would image that you could use some limiting straps to limit the travel were you are comfortable with the pinion, then unstrap it when it is time to take the wheels and tires off.

well I don't have a pinion change currently as it still is in a design phase and I keep changing it around trying to work all of my factors.

It's a two door SUV, that ideally I would like to keep a backseat and run a triangulated four link. The more I think about it the more it comes down to one simple question, do I want a back passenger to be comfortable and I think I've decided that I truly don't give a damn, lol.

mike you can allways bend your upper bars for clearance or make them out of box tube like i did on the explorer.

I'm not a 2-link fan at ALL, but what about it as a 2nd option?

Originally posted by slammed x on air



mike you can allways bend your upper bars for clearance or make them out of box tube like i did on the explorer.

I think no matter what I do that will have to be done. My concern was the front pivot points still need to be high in order to get the right design with correct instant center and limited pinion angle change.

I think one thing I might look into is just putting all the points directly behind the front seats, since it is just so short anyways, then the floor could possibly drop down some in between there and the back.

Sorry guys, I just have a thousand thoughts running through my head. I truly think I should wait until I'm closer to actually setting up the four link before I get too ahead of myself, because depending on how high up the driveshaft comes into the cab it might be as simple as adding 2" to each side fo the tunnel in order to fit the upper link mounts in.







I think I would just run a parallel four link/6 link before I went to a 2 link. That would be my last resort because I have the same despise for them as you do most likely

Your question about if there is any anti-squat if the instant center is at the bumper is a good question. The further away from the rearend the i.c. is from the rearend the less dynamic input you will get from the suspension. On a drag car, the i.c. would be run only a few feet in front of the rearend with relatively short bars, this transfers more force to the tires. Running a system like that on a daily driver can cause an undesireable amount of roll-steer.

In my oppinion, there is never an excuse to use a 2-link, there are ALWAYS other options. There really isn't any reason why you can't run short bars that keep everything well within an acceptable working range. Look at the Nash in my profile, the bars on that are really sort.

I just took a couple more measurements.

With 28" long bars the mounts will be about 2" under where the factory seat is, which really isn't a big deal to me since the floor is raised up there and can fit under there.

I've had one other question come up for you max, one of the simplified theories is to keep the lower bar preferably close to parallel with the ground at ride height. You also state that the IC should be preferably at the grille. wouldn't that by definition mean that the lower bar mounts have to damn near be the same level as the grille?

Or you simply stating near the grille in a length dimension not a length and height dimension? As in as long as the IC is at the front of the truck. By having it at the grille you would have more anti-squat but your pivot points would have to be very high relative to the frame or have the lower bar angled up.

I get asked that a lot. On most lowered vehicles, if the bars are near parallel(ish) then the i.c. will be near the grille.