Comanche Build, Dr. Thunder's

[DrThunder]

Someone tell me if I'm on the right path. I've done a lot of reading and stuff and it seems I'm doin alright with these numbers. My uppers are about 3/4 my lowers length and the frame separation is about 3/4 the axle separation. I dunno it's hard figuring out all this shit but I like the lower mounts where they are cause they are not lower than the axle tube and allows me have a flat belly

I can make the upper links out to 28.5 which I like the sounds of but I've read keep the uppers about 3/4 the lowers. The anti squat moves to 85%, the instant center on the X moves to 143, and the instant center on the Y moves to 40. I'm fairly sure that those numbers aren't as good as the numbers below. Someone tell me. I'm gonna start tearin shit apart.

[Pedro]

I was reading OFF-Road Magazine the other day and they have a 3 or 4 page write up on making a solid three link setup. I'm sure the info is online too. Just lettin you know I didnt read it too hard.

[XJLI]

post on pirate

[OWEN]

Someone tell me if I'm on the right path. I've done a lot of reading and stuff and it seems I'm doin alright with these numbers. My uppers are about 3/4 my lowers length and the frame separation is about 3/4 the axle separation. I dunno it's hard figuring out all this shit but I like the lower mounts where they are cause they are not lower than the axle tube and allows me have a flat belly

I can make the upper links out to 28.5 which I like the sounds of but I've read keep the uppers about 3/4 the lowers. The anti squat moves to 85%, the instant center on the X moves to 143, and the instant center on the Y moves to 40. I'm fairly sure that those numbers aren't as good as the numbers below. Someone tell me. I'm gonna start tearin shit apart.

Ok, for starters, where did you come up with your CG height and vehicle mass? Try playing with them and see how it affects things. In other words, if it is am educated guess, the numbers are less significant... So make your brackets with multiple holes so you can fine tune it once its done.

I am not familiar with the 3 link setup at all or the calculator, but if it is anything like the 4 link calculator, I would focus more on the dynamic aspects. Try to build something that has a higher number antisquat as the suspension compresses, and a lower number as it droops. I feel this is more important then dialing in a static antisquat number with made up CG heights and vehicle weights.

Is this a front or rear setup. Hope I was of some help. Good luck

[Ktmracer419]

less anti squat= more level ride height when accelerating up obstacles

higher anti squat= front axle gets pushed down when accelerating up obstacles, which in turn means better traction, but more pucker.

i have read that most guys shoot for a 50-100% as

and the roll axis you want as close to zero as possible.

thats all i know.

[DrThunder]

This is for the front, I copied the cg height from another cherokee build online but he was running more lift. I compensated for that.

[OWEN]

I shot for around 90% AS on my jeep and it is pretty neutral handling, not serious dive or lift under acceleration. Whether or not that number is real I cannot say, I do not know the actual CG height or vehicle weight, I estimated them.

What I did was put in 1" Droop, 2" Droop, 3" Droop, and so on, and 1" Compression, 2" Compression ... You get it.

In other words I think the best idea is if you have 80%AS at static ride height, when you accelerate it might squat a little. Now picture this scenario: you are launching at a hill climb. You want a little AS to help you get some traction when you dump the clutch, but as the suspension compresses, you don't want the AS numerically to decrease.

So you started with 80%AS static. At 2" compression, if the AS is now 60% and 50% at 3" Compression as you lay into the throttle, the way I see it is you are going to really feel the vehicle squat. On the other hand, if you start at 80% and then at 2" compression it is 85% and increasing, you are not going to feel as much of the squat. You get your initial traction when you lauch it, and as you stay into the trottle you don't lose the torque to the suspension.

The same goes for droop. A big problem that a lot of people talk about is a vehicle hopping. These people might have a design that has increasing antiquat as the suspension droops (extends). Of course we know that the antisquat is the resisting force to the tire rotating the vehicle about the center of gravity. So anything over 100% is actually going to lift the vehicle under acceration, causing the suspension to extend (droop). Rigs that hop on hill climbs probably start out at 100% AS and is the suspension unloads, there is increasing anti squat. At 2" Droop you might see 110% at 4" you might see 120% and so on.

All this being said if you have a design that is supposedly 80% antisquat, mess with the CG and see what happens. It can go close to 100% pretty quick. That can be the difference of having a 175lb passenger, a winch up front, or a full tank of gas. Therefore as I said, it is more valuable to look at it from a dynamic standpoint.

Take all of that with a grain of salt, it is more applicable to a rear setup, but the idea of a "dynamic" design being most important (in my opinion) still applies.

[Ktmracer419]

for what its worth my 210% AS radius arms pwned the bonus line at rc the first comp.

some of the 3 linked guys didn't make it.

im sure if i ran a 3 link i would like it. but all i have experience with really is my radius arms. i never really wheeled hard when i was 4 linked

[DrThunder]

Just dumpin a link.

http://pirate4x4.com/forum/showthread.php?t=782105

[DrThunder]

Slight change of plans, changed the geometry around a little and got my numbers pretty much perfect, all of the numbers are exact to what they will be with a little front axle stretch to make a little extra room for big tires . I measured where the mounts are related to the jeep at the ride height it will be at so none of these numbers will change. I am going to be re-using my old lower mounts and my upper will be attached to my frame. Frame plating to come and more!


Found out at work today that I'm gonna be workin 12 hour shifts with one day off (wednesday) at night 6-6 until the plant is up and running again. But that means I have all night to work on this jeep . I woke up at 6am today, worked 12 hours and now I'm gonna try to make it to 4am so i can at least start to sleep during the day and get used to the change. The good news is I am getting lots of overtime and sunday is double time so I'll be makin like 40 bucks an hour. AND i am getting 8 hours rest pay on my day off wednesday so my paycheck is gonna be amazing!!






PICS TO COME LATER!!

[XJtheXtremeJeep]

That is freakin awesome man, thats pretty much how my work schedule was 3 weeks ago

[OWEN]

What company do you work for? I just started working for Covanta Energy as a Plant Operator. All of my shifts are 6-6 days and nights alternating

[DrThunder]

What company do you work for? I just started working for Covanta Energy as a Plant Operator. All of my shifts are 6-6 days and nights alternating

I work for dominion at millstone power station. I'm a nuclear mechanic. What kind of plant is covanta?

[OWEN]

I work for dominion at millstone power station. I'm a nuclear mechanic. What kind of plant is covanta?

Waste to Energy...we burn garbage, it is pretty neat

[DrThunder]

Update, 3 link is gettin close. Need a axle trac bar mount and to finish the upper control arm mounts with more bracing.












This is how it will sit at ride height. 6-7ish degrees castor right now too. Lookin like progress to me. I stayed up all night and worked on it. Time for bed. nunights