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Old October 2nd, 2007, 12:09 AM   #21
bigblocked
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With those lower mounts located so high on the axle you're going to definately get huge amounts of squat (which is actually the axle being lifted into the chassis and not due to the weight of weight transfer). Take the upper mounts out of the picture, imagine you have your lower bars suspended and no uppers. What's the axle going to do? Flop down, not back or forward. Now imagine hundreds of lb ft of torque applied. In your case the lower bars are not naturally pushing forward but are trying to push upward due to the location of the mount. The entire topic of link bars is really a huge topic and many books have been written trying to help drag racers understand and tune them. I know you're not a drag racer but the principal is all the same. I'll try to give you a small example of the leverage on the lower mount; a Foxbody Mustang with a stock rear link setup will typically "squat" a couple inches on WOT launch. Even more on the pass side due to torque. Now install some Southside lower trailing arms and adjust them with the full drop of about 1.5 inches and all of a sudden your rear is being forced downward instead of upward. If you've ever seen a car at the drag strip that actually lifts the back of the car at launch it's due to an adjustment either lowering the bottom arm or altering the angle of the upper (or about 60 other combinations). This actually increases traction considerably due to the chassis pushing the tires into the track and not pulling them from it. I would bet a paycheck that if you mounted the lower arm to the bottom center of your axle you would be perfectly fine. If you want to check out some literature I'll try to find some of my old books at home and give you the titles for reference. But beware, it will give you mind freeze real quick.
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Old October 2nd, 2007, 07:14 AM   #22
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I'm not going to lower my axle end lowers, that would be counter productive in that I would loose clearance, move my instant center back and loose stability, get rid of my flat roll axis and move my anti squat number around a bit.

I think JohnnyJ is onto something. at the badlands I was hitting things HARD with just the front tires up the ledges. time to make it stronger
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Old October 2nd, 2007, 07:41 AM   #23
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you better hurry, you only have a few days.
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Old October 2nd, 2007, 07:46 AM   #24
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Quote:
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If you want to check out some literature I'll try to find some of my old books at home and give you the titles for reference. But beware, it will give you mind freeze real quick.
I'd be surprised if geodad and geoboy don't have a worn out copy sitting either near in the shop or near the computer; but I don't think it comes down to the squat/antisquat forces.

Based on what I've seen at dragstrips, most well built 4x4 links are built heavier duty than a similar size/weight drags car. I'd be impressed that even with his new found power in his v6, launching in stupid low with a set of race slicks on a properly dressed track if he'd even tweak a mount.

I'd still put money it's the balls out trying to pull yourself up a ledge with your nose pointing straight in the air, and then sliding back down after failing with all of the weight being transferred through the body through the links. I think the worst case is when the ledge is just a foot or two longer than your wheelbase and you're sliding back down into rock.

I ripped my driver's side lower control arm frame mount out at the badlands doing this and coming down on just my drivers side tire. Then this last summer I broke a lower control arm bolt (5/8" grade 8) doing a similar thing on the passenger side. They were both similar maneuvers, both things I probably would not have attempted back when it was a DD.
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Old October 2nd, 2007, 07:53 AM   #25
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Your frame side upper link mounts have plenty of stability parallel to your frame (pulling straight back) but they don't have very much at all from side to side.

With the way you have it now, the long brackets from the cross member will let the links roll (red arrow), bending the inside tabs enough to break or crack the welds.

If you want to keep the upper setup you have now, you could weld the nut to the upper brackets and box them in frame side (yellow line) then run a plate just in front of your JJ's welded to the frame and bolted to the bracket from the cross member (around the blue line). But you know your setup better than I do, there may be a better way to just remake the whole deal.

I dunno about your axle side upper mounts... they look plenty stout to me.

Having your lowers above centerline puts a lot of force on your uppers as well. But you already knew that when you did it that way.
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Last edited by Monkeyevil; October 2nd, 2007 at 07:59 AM.
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Old October 2nd, 2007, 08:01 AM   #26
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I have a gusset on the front side, you can barely see it in this pic



Im going to figure something out tonight before I put it on the trailer for canada.

I can actually stand up for more than 10 minutes at a time now so I should be able to get it done.
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Old October 2nd, 2007, 08:08 AM   #27
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Quote:
Originally Posted by 95geo View Post
I have a gusset on the front side, you can barely see it in this pic



Im going to figure something out tonight before I put it on the trailer for canada.

I can actually stand up for more than 10 minutes at a time now so I should be able to get it done.
Ah ok, that makes more sense.
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Old October 18th, 2007, 08:30 PM   #28
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stop web wheeling geo boy and worrying about numbers that just get thrown out the window the instant you aren't on flat ground and go wheel
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Old October 18th, 2007, 08:49 PM   #29
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stop web wheeling geo boy and worrying about numbers that just get thrown out the window the instant you aren't on flat ground and go wheel
hey!

looks who's web wheeling now....

it actually matters though, my rear crossmember (pictured above) broke between the mounts. not how you would think though. the rear side of the tube broke and not the front as if the lowers pulled rather than pushed.
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Old October 18th, 2007, 09:02 PM   #30
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just do a burn out. then stop and pause. look around. then say to yourself. " I just did a burnout in a fawking geo". proceed to grow a mullet and start running the tractor pull circuit.
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