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Design, geometry and functionality of tracbar-less suspension

Kacz, the limiting strap absolutly works, in fact, now that I finally installed one, I consider it to be necessary! Well, at lleast as far as I know on long radius arm set-ups....

the difference is remarkable.......

however, I can't wait to see if there is a better way.....lookin foreward to responces.....
 
I started running a center 'sling' style limiting strap on the front axle several months ago..... huge difference.
Totally agree with Beez's experience; the center limit strap works and the difference before and after on the same obstacles was tremendous.
 
Is the benefit of the strap due to it limiting the unloading of the front, or does it somehow help pull the front back onto terra firma, and help with traction? (i.e. increase anti-dive?)
-Jon
 
By holding the front end down I'd say the answer is both.

Before I had the strap the front would unload to the point I almost went over backward on a couple of occasions and had to back off obstacles. All the time my front wheels would still be on the ground but rather than pulling up, my body would just separate further and further from the front axles until my side limiting straps were tight and it began to pull or untill I had to back off.

With the center strap it can't unload as far. This keeps more of the weight of the vehicle over the axle and thus increases the traction to the front axle. Less unloading = more traction.
 
Sounds like a good reason to run active suspension, load and unload whatever wheel you want at will.

XJguy
 
Who has drawn out something like this?


FRollAxis




I left out the last step of drawing the actual front systems roll axis between the two points on the axis itself (because it would obscure the UCA).

If your doodles look anything close to this, you can scratch out a full size analysis of your factory XJ suspension on the garage floor (and then make changes to learn why it acts the way it does when lifted).

Is this worth the effort?
 
Beezil said:
i did i did !!!!

next lesson please!
Click to expand...


Quiz:

Draw the control arm system after changing the two UCA's to a centered three link with the 3rd link behind the axle centerline (your original question).

Find the roll axis?

Extra credit:

What are your choices to level the roll axis?
What system makes leveling the roll axis easier: three-link or four-link (remember there is a vehicle & engine in there)?
 
Ed, may I please have an extension???

have to attend to some non-jeep matters over the next few days.....

will this affect my end-of-the-semester grade?

I need to spend some time under the jeep with a tape measure and figure out what version A of my planned suspension will be for a group critique....

jnj.....callin me a front row nerd?

yer just sore me and my friends beat you up and stole your lunch money....

band geek loser.
 
Beezil said:
Ed, may I please have an extension???

have to attend to some non-jeep matters over the next few days.....

will this affect my end-of-the-semester grade?
Click to expand...


No, it's your thread, but the smart boys in the back row will be targeting you for spitballs when you return (and the girls will be armed with soggy peas). Make sure your shirt tail is tucked in.

I'll be teaching a 4x4 class this weekend and also need a break to prepare.
 
Let's bring this thread back to life....

I figure the roll axis in the sketch looks ok at ride height, but at 10" of drop, it gets WAY high (~30 degrees by my crude calculations). It seems this would get very tippy in off camber situations. Do you radius-type long arm guys have this same issue?

I'd like to keep the suspension predictable in all types of terrain, even though it will be used as a trail only-slow speed rig. How can I keep the roll axis flatter given the limited space for the triangulated arms, or am I over-thinking the whole design?

Thanks, Jon
 
Sorry for my inexperiance, but has anyone ever experimented with a watt's linkage style track bar? Fairly common on older roadrace cars, could it be adapted to a 4 wheelin application?
 
A watt's linkage in the front would require full hydraulic steering in order to keep bump steer out of the equation. It also complicates the front geometry, which reduces the primary benefit of a triangulated front 3 or 4 link-- simplicity, and NO track bar.

-Jon
 
also, the arms on the linkage itself would have to be pretty big to allow for droop and stuff.......

this thread back to life?

cool.

this coming week I GOTTA-HAFTA start designing, cause I wanna hang the new front axle in the next few weeks.......

if this thread dips to the bottom, hopefully whatever I come up with will get Ed's attention.
 
Would it be out of the question to just coppy Teraflexes LCG kit? im wondering because it is triangulated and seams to work. read about it in i believe JP and when i met Dan Mick he had one of there chassis waiting for the body on the other side of yard. so im thinking it may simpilify but that may not be what u want to do.

WIll
 
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