Antisquat,Your rig and how it reacts

[desertCJ]

First off, let me say that I know of NO other place to find as much info on link design and theory for rockcrawlers than right here on the PBB. Still, after hours and hours of searching and reading it's easy to find yourself with a headache....still scratching your head. I'd say the most common question regarding link suspensions is "What amount of antisquat should I build into my system?" We all know that there is no perfect answer to this, so what I'd like to do is get a list going of what antisquat% your rig has and the actual quirks that you notice in the real world.

My old Jeep had about 80% antisquat by my estimations and I read on here that was about perfect. It performed great in all situations I put it in for a long time, then I watched a video of me trying to climb the waterfall on Backdoor and I noticed my rear suspension was loading and un-loading. Now I realize that I actually had squat going on and it wasn't working so good! I made it almost to the top but it seemed like my rear tires just wouldn't plant on the ground :rolleyes: There goes my "Perfect 80%"......I'm now thinking of building my suspension at 100%-120%.....

So what do you have and how does it act and how do you like it?

Edit: The four link calculator http://www.isd623.org/ben/jp/fourlink/ is an excellent tool! Learn it, use it....love it :cool2:

[P&T Jeeps]

I plugged in my first suspension design (which failed miserably) to the best of my recollection & came up with 189% AS! :eek: It was a radius arm design which just does not work for the rear. It lifted it's ass so high under throttle that when you were climbing something you felt level. It did hook up damn good....well sometimes too good as the axle ended up driving under the rig.

w/o having my Jeep to measure exactly (but I feel I know the numbers fairly well) my current 4-link came in at 87% AS which I am happy with. Although I am going to adjust it when I swap the D60's in to get it to 105% to aid in traction a bit more.

[BadAZYj]

By the 4 link calculators measurements I have about 96% antisquat, that is guessing on my CG though, so that could be off a little. But it works damn good. So far its climbed everything Ive tried(except for the winch only fall on UPG, I rolled on that...)

[elf_cruiser]

I can attest that BadAZYJ's works great. I used to run about 130-140% AS and it hopped pretty good. At first I was using two shocks on each side in the rear and that kept it controllable, but since going to the air shox it has gotten worse. I remade my upper frame side link mounts to get more squat, I don't know what the numbers are but I know it squats pretty good. If I had to guess I'd say about 70-75% AS. I have only tried two climbs since the new link mounts and no hopping at all on either of them. It just sqauts down to the bumpstops and spins the tires.

[desertCJ]

It squats all the way down to the bumpstops :eek: I guess air shocks are really soft though...I just ordered mine :D That's another reason I want to get away from the squat side of things. I used to run 1/4 ellip springs and on the video I was talking about you can see they compress and then unload while I'm on the fall spinning the tires. It basically created "wheel hop" but it was more like suspension hop. Stiffer shocks may counteract this, but I'm thinking a little over 100% is what I want....I'll put a limit strap on if it ends up too bad.

[Strange Rover]

I think all the new moon buggies are runnning close to 0% (links parallel and horizontal to the ground). If you want stable and no hop then lower is better.

Sam

[elf_cruiser]

Strange Rover - I think when you say 0%, you're meaning 100%. 0% would mean that the IC point is horizontally level with the front tire's contact patch. this would be very hard to accompish, and I haven't seen any rockcrawling suspensions that are even close to this.

[Triaged]

Strange Rover - I think when you say 0%, you're meaning 100%. 0% would mean that the IC point is horizontally level with the front tire's contact patch. this would be very hard to accompish, and I haven't seen any rockcrawling suspensions that are even close to this.

The links don't have to point at the front contact patch to get 0%. All they have to do is bel parallel with the ground and parallel with each other. This way the IC will be at infinity (where is that stupid sideways 8 key when you need it). You can play with my link calculator a bit to see this.

[desertCJ]

Regardless...0% is not really what I'm after. It's actually what I don't want. I think the reason the moon buggies have that type of suspension is so when you get on the throttle, the suspension sinks down to the bumpstops and get's really solid. Maybe that is good, but those guys aren't here telling us how much antisquat they have and how there moon buggies are acting, so that leaves us guessing. Guessing and speculating doesn't do us anygood, that's what's been going on for years and everyone still has there own idea of what is good.

[elf_cruiser]

The links don't have to point at the front contact patch to get 0%. All they have to do is bel parallel with the ground and parallel with each other. This way the IC will be at infinity (where is that stupid sideways 8 key when you need it). You can play with my link calculator a bit to see this.

Right - I'm following you. My links are now parrallel, but angled up slightly, maybe 10*. How do you calculate AS when you have an infinite IC??

[desertCJ]

How do you calculate AS when you have an infinite IC??

I don't know, but go take some measurements and plug it all into the first link I posted. Triaged was one of the guys that put that together.

[Hosejockey]

i was wondering how you guys come up with your COG im just guessing that mine is somewhere around the midline of my bellhousing

[JohnnyJ]

what I wrote originally was wrong so I deleted it.. my memory sucks. the post by TR in this thread (http://www.pirate4x4.com/forum/showthread.php?s=&threadid=70358&perpage=25&pagenumber=3) explains how to find the AS% with parallel links.

hosejockey: that's an ok estimate, if you're looking for more exact either try to find a guy with portable scales that can weigh it for you, or drag it to a truck stop or junkyard and weight it on their scales and do what they tell you in this link (http://www.jeepaholics.com/tech/cog/)

[elf_cruiser]

Thanks JohnnyJ - that explains it perfectly - now I see why I have so much squat...