Project Geosynchronous Orbit

[foxwar71]

I don't think it will matter on a 3 link how triangulated they are...?

I'm no expert though.

Ehhh, it shouldnt be too much of an issue, just check for bind on full flex and stuff. Thats alot of angle though, those LCA's are tucked far inward. Why inboard them soo much just to clear the frame? Just notch the frame to clear on full stuff.

 

[MoparManiac]

I don't think it should be a big deal.

Bill has 18* on his LCA, and I'm at 22*.

 

[ktm racer 419]

Only way I could do it with the way the control arms positioned:
1. Axleside brackets are pretty much butted up against the knuckle
2. Need to clear the frame and keep the rig low
3. Want to keep the brackets on the crossmember side from hanging down too low.

I don't think it will matter on a 3 link how triangulated they are...?

I'm no expert though.

me either. but for fun i just went and played with my midarm file on my 3 link calculator and inboarded em'

roll center stayed about the same

roll axis went negative


but i dont know what they mean anyway lol. all i remember is looking up "acceptable" figures and making sure i was in the ballpark at the time i was buildin it lol.

 

[MoparManiac]

Yeah I have no idea what any of those numbers mean either haha.

 

[kastein]

My only worry would be driveshaft interference on the driver side frame end LCA mount.

I would worry about link setup buut I am retarded when it comes to that so it looks great to me! :dunce:

Any reason you couldn't put a bend in the LCAs so they hit the crossmember further out, come forward parallel, then angle out to the mounts on the axle? Aside from the obvious strength reduction and the fact that they would go everywhere when the joints rotate, that is.

 

[MoparManiac]

My only worry would be driveshaft interference on the driver side frame end LCA mount.

That was mine as well, I checked and it clears it at full droop and then some. :thumbup:

Any reason you couldn't put a bend in the LCAs so they hit the crossmember further out, come forward parallel, then angle out to the mounts on the axle? Aside from the obvious strength reduction and the fact that they would go everywhere when the joints rotate, that is.

My only concern is bolded.

I know that TNT bends their lower arms for this exact reason, but I'm not sure if having the upper arm in the y-link right at the bend gained some strength back or not.

Either way, I think this should work ok.

 

[RCman]

You'll be fine with that setup. Stop worrying about it and keep the progress going.
Those commenting haven't even cut their PVC yet. :laugh3:

 

[vetteboy]

Only way I could do it with the way the control arms positioned:
1. Axleside brackets are pretty much butted up against the knuckle
2. Need to clear the frame and keep the rig low
3. Want to keep the brackets on the crossmember side from hanging down too low.

I don't think it will matter on a 3 link how triangulated they are...?

I'm no expert though.

Yeah, pretty much as long as your joints don't bind, you probably won't notice any issues.

What it'll do vs. having them straighter...when the panhard swings the axle side to side, it'll also make it become less 'square' to the truck. In other words, picture a square compared to a trapezoid. If you move the bottom of a square over it stays parallel (as in, the shape becomes a parallelogram). If you move the bottom of a trapezoid over, the top & bottom lines aren't parallel anymore.

I don't think yours is severe enough that you'd notice it, but that's really the only strange 'physical' thing that happens.

With regards to clearing the frame...I wouldn't really keep that as a driving factor. Honestly mine was close enough that I decided to just let it self-clearance. Aside from being far less work, all I have is a little curved dent on the bottom of the frame...this seemed a better solution than chopping out and welding in a bunch of patch pieces. And obviously it hasn't been a problem.

Are you also concerned about the tires clearing the links at full steering?

me either. but for fun i just went and played with my midarm file on my 3 link calculator and inboarded em'

roll center stayed about the same

roll axis went negative

Roll center is fixed at the midpoint of the panhard, so that will stay the same.

If you draw imaginary lines along your lower links and find the point where they meet, and then draw a line from the roll center through that point, that line is your roll axis. If you keep the same angle on the arms from the side view and just inboard them, that point gets closer to the roll center so the axis tilts down more.

Usually with the arms inboard more it'll give a 'flatter' roll axis, or in other words, it'll have less flex steer. The steeper the roll axis the more flex steer you'll have. On a steering axle though you usually won't notice it at all unless you've got some really oddball geometry going on.

 

[kastein]

Are you also concerned about the tires clearing the links at full steering?

hey now! no fair!

we only give Ross crap about that :roll:

 

[MoparManiac]

Yeah, pretty much as long as your joints don't bind, you probably won't notice any issues.

What it'll do vs. having them straighter...when the panhard swings the axle side to side, it'll also make it become less 'square' to the truck. In other words, picture a square compared to a trapezoid. If you move the bottom of a square over it stays parallel (as in, the shape becomes a parallelogram). If you move the bottom of a trapezoid over, the top & bottom lines aren't parallel anymore.

I don't think yours is severe enough that you'd notice it, but that's really the only strange 'physical' thing that happens.

With regards to clearing the frame...I wouldn't really keep that as a driving factor. Honestly mine was close enough that I decided to just let it self-clearance. Aside from being far less work, all I have is a little curved dent on the bottom of the frame...this seemed a better solution than chopping out and welding in a bunch of patch pieces. And obviously it hasn't been a problem.

Are you also concerned about the tires clearing the links at full steering?



Roll center is fixed at the midpoint of the panhard, so that will stay the same.

If you draw imaginary lines along your lower links and find the point where they meet, and then draw a line from the roll center through that point, that line is your roll axis. If you keep the same angle on the arms from the side view and just inboard them, that point gets closer to the roll center so the axis tilts down more.

Usually with the arms inboard more it'll give a 'flatter' roll axis, or in other words, it'll have less flex steer. The steeper the roll axis the more flex steer you'll have. On a steering axle though you usually won't notice it at all unless you've got some really oddball geometry going on.

Sweet, thanks for the input Chris.

Tire clearance is about my only concern at this point seeing as how everything else should be good. I had the drivers side outers mocked up with a tire mounted, but couldn't really get it seated correctly because of the 1/2" studs that are on there (lug nuts were too small for the wheel).

Planning on cleaning up/assembling the front outers with the solid knuckles one night this week so I can get the tire/wheel mounted correctly and be 100% sure it's all set. When I did a rough mock up of the tire, it looked like it would clear fine at full lock.

 

[foxwar71]

Those commenting haven't even cut their PVC yet. :laugh3:

Links are ghey, I shoulda done leafs with Billy.

we only give Ross crap about that :roll:

My junk is gunna be all sorts of fawked.

 

[MoparManiac]

Suckered my father into helping me mount the last two 40s tonight.

Also, in case anyone was wondering, regular 9/16-18 60 degree conical lug nuts don't have a wide enough contact area to fully seat an H2 rim (read: the hex part of the nut just digs into the wheel).

I found out through some research that factory CTD lug nuts (like off of my '01 2500) work perfectly.

Dorman 611162
Type : Bulge
Thread : 9/16-18
Hex Size : 15/16"
Length : 1-1/32"
Seat Angle : 60 deg.
Finish : Yellow Zinc

 

[MoparManiac]

Figured out where the UCA needed to sit and made that mount. Cut the floor and fitted it up. It's probably about 5* off from straight to clear the bellhousing/starter.

Built it to be adjustable for either 6.5" or 7.75" of vertical separation. All the control arm bolts are 5/8" BTW.

Also turned the LCAs in a few degrees since they weren't pointed exactly where I wanted them, and trimmed a bit off the bottom to make them completely flat (you can sort of see this in the last picture)

Started cutting out the axleside UCA mount (will have 8" of separation). Gonna do that and the LCA brackets on the axle as well. Going to NH with my gf for the night tomorrow so I don't think I'll get anything done until Wednesday.

 

[foxwar71]

Now thats an Adv Fab approved crossmember :thumbup:

 

[ROBZ95Xj]

Now thats an Adv Fab approved crossmember :thumbup:

X2 Bitchin' work dood!

 

[rweaver138]

dammnnn those 40's look sexy... can't wait to see this thing at NAC fest... or earlier

 

[MoparManiac]

Thanks guys

Currently in N. Conway, NH watching Monday night football on a 40" plasma in a jacuzzi

 

[MoparManiac]

Had a physical this morning so I got a late start (per usual).

Cleaned up the hubs that I got back from my parts guy with new rotors/races and the 9/16" studs all set up.

That grease was like peanut butter :shocked:

All better

Mounted everything up to check for link to tire clearance at full lock. Clears by about 1/2". The link is further outboard than planned, and the tire is what I believe to be beyond full lock based on measurements.

Jealous of my gold lug nuts? Mad bling

Also cut out the rest of the control arm bracketry for the axleside.

UCA mount set for 8" of vertical separation.

One of the short LCA tabs (far right) got trimmed up to be welded to the cast portion of the diff. Going to tack everything up in the morning to check clearances again. Ross is going to come over in the evening to help me weld up the tubes on both D60s (don't trust myself).

Since I can't finish the front axle without a steering ram, I'll start working on the rear axle tomorrow once the control arm mounts are tacked in. Going to make some UBEs for it, and set it at the right pinion angle and tack those in. I might even burn them in considering they aren't reliant on anything else.

 

[5spd_xj]

very cool mannnnn

 

[foxwar71]

One of the short LCA tabs (far right) got trimmed up to be welded to the cast portion of the diff. Going to tack everything up in the morning to check clearances again. Ross is going to come over in the evening to help me weld up the tubes on both D60s (don't trust myself).


Going to make some UBEs for it

Im gunna weld boogers all over it!!!!


PS- dont make UBE's, I have an extra set of the bases. the first version I made with the holes all squared up on the 2x6, but i need to build an offset pair to clear the narrow brake flanges on my C&C 14b.