nonnieselman

iTrader: (10)

What bolt pattern is that??

Give it a try and let us know how it works..
you could even put holes at different lengths on the bar that contacts the leaf for different leverage points.

sprayedenali

iTrader: (11)

Since I'm not on the up and up about all the instant center stuff, I didn't take that into account. And if changing the IC is what caltracs do and your idea won't change that why not just make a standard set of long bars?

TXsilverado

iTrader: (19)

standard set of long bars prevents axle wrap, but does nothing to redirect the energy like cal-tracs design does.

sprayedenali

iTrader: (11)

Ya, that's exactly what I'm saying... I think! Haha. If his design won't "redirect" energy, wether it be due to the instant center or whatever else, why not just do a simple set of long bars?

TXsilverado

iTrader: (19)

if i'm reading his kindergarden art picture correctly, atomic is trying to redirect the energy with his design.

Atomic

iTrader: (42)

As the leaf sits now, between the front hanger and the center where the axle is is almost perfectly straight. Also keep in mind its not really the front of the leaf that moves, after all it is on a fixed hanger and only has 1 degree of freedom, but the rear of the leaf is on a shackle and has 2 degrees of freedom. When you go over a bump and the spring compresses, it is the rear shackle that moves and the rear part of the leaf that stretches the most, not the front.

My reason for wanting an adjustable setup with heim joints is to be able to shorten and extend the rod length thereby controlling the distance from the axle center mount and the front bracket. If extended enough so the bracket is not in contact with the leaf, it will basically do nothing because everything has room to pivot with the suspension. Which means you can adjust it so you only stress the parts when you want to and its invisible the rest of the time.

It is true the ubolts will be stressed, but as you can see in the picture below, these are not normal ubolts. The nuts are very tall and the ubolts are 5/8 hardened steel. When the plate is sandwiched between some of those nuts it will be a very solid unit. Additionally, the bars will only be "active" when the rod is shortend, such as at the track or whatever else.

There will be downward force on the spring, but I do not believe it will be near enough to bend the spring because there are actually 2 leafs there and the distance between the pivot and back of the triangle bracket will not be that long, limiting the moment on the spring. Also, during axle wrap the front of the spring is actually trying to rise, so having it push directly back down on it should help counter act that directly. Typical traction bars do this by not allowing the axle to move forward.

The potential of unloading I think will go back to the shocks I use...I feel it going to a combination of some fancy shocks and traction bars that cure my issues.

If you mean use the rear shackle and axle mount...this basically turned around...i dont think that will work because I have a lowering shackle which puts the angle of the bar such that it will hit the bed even without any downward travel, while there is plenty of room in front of it. Or perhaps I didnt understand what you mean?





I measured maxiumum height of the triangle bracket can be about 9", which I much taller than I think I will need. Max height above the axle of the bracket will be about 5", and the fender can be trimmed 3/4" to the bottom of the bed if I need it if I have excessive downtravel. Approximate distance where I think the bars will be is about 24" and I have 4" in front of the spring clamp and hanger if I dont want to remove the front spring clamp. I am going to try to throw these numbers into a better sketch today sometime.

Whplsh, it should be the same force if you push on the top or the bottom, as long as the pivots are the same distance from the axle center. Same thing as pulling down on the left of a wheel or pushing up on the right; same moment. In fact, I think mine will have more leverage than either of the others because it is so far away from axle center. This is also why I want some adjustability in the mounting holes.

Roger, because I plan on keeping it 4wd I dont think I need to modify the IC too much since I still want the front wheels planted as well. But this is the part of the design im not sure about. Like I said before, I think my solution will be a combination of fancy shocks and something to prevent axle wrap (like this). I blame the unloading problem im having on too wimpy of shocks. Most guys that try to move the IC forward are trying to lift the front tires so all the weight transfers to the rear, but since im 4wd, I dont want the front to lift at all. Sadly, there just isnt a lot of common info out there on 4wd/awd drag setups, especially for leaf spring setups.

Tx, the bar will basically be in the fender, so there is plenty of room, and there is actually a lot of room behind the front hanger. Not sure what those brackets are for


Good discussion guys, keep it coming

Atomic

iTrader: (42)

Right, with long bars you basically just have the bottom of the axle pushing up on the frame lifting the truck upward. With caltracs, and hopefully my design, the energy of the axle trying to rotate upwards is redirected downward onto the spring, using that energy to put more force on the tires.

1FastBrick

iTrader: (17)

Richard, its the Shock load that causes the damage to the plate and the bolt. That's why they us AN bolts on rockets, planes, race cars and not standard grade 8 bolts. The thread is smaller then the shank of the bolt and it will eventually elongate the hole and wear the bolt down were it makes contact. You want to minimize the the the amount of clearance between a bolt and the hole that it fits through. That's why I would not recommend mounting up above the spring that high. Do it right off the plates.

Perfect example would be lets say your control arm has a 5/8 Hole in it and you use a 1/2 inch bolt. The 1/2 bolt alone would do the job and with stand the shear force placed on it by the moving part. How ever since it's not a precise fit, it will move. As it does this it's only going to contact the area less then 1/2 way around the bolt putting all the stress in the center at the contact. As it keeps doing this it's going to wear out the Hole and wear down the bolt eventually causing it to fail.

On to the Second order of business. The way you mount the front bracket behind the leaf mount and have the pivot point is going to cause a bind in the suspension as the axle tries to wrap upward and the spring tries to flatten out.

I am convinced that if you take the assassin design, flip it up side down to use on the top and mount it to the rear it will function very similar and accomplish the same thing with out the loss of ground clearance.

WHPLSH

If you are running 4wd and strap the front end the lifting forces will push the rear axle down which will increase bite instead of lifting the front end. Real race cars dont squat, when a car squats is takes away the downward force thats applied to the tires. you want the rear to lift slightly to apply more force on the tires. If an axle over bar worked it would be used already. like everybody has said yes your design will work with axle wrap but thats it.

Atomic

iTrader: (42)

Is that not the point of preloading, to reduce or eliminate shock loading? I fail to see an issue because you could make that same argument about any bolt that sees cyclic loading...

To be clear, you are talking about my idea of stacking a second plate on top of the nuts that are already there? Why not just weld a bracket on to the plate thats already there? Or is that what you meant? If so, how is it not the same thing as stacking a plate on top in terms of bolt shear?

I see what you mean about putting it on backwards...but I dont think I have room for a bar right there....time to measure again.