scale long-arm upgrade
 

I have seen alot of builds with 4-linked axles. Every time, i see the upper and lower control arms attatched to the frame seperately. There are some 1:1 4-links out there like that, but there are also ones such as the Rubicon Express and TnT customs long-arm kits (for jeeps) where the upper arms are attatched to the lower arm. Has anyone done this on their scale rigs to give it that extra scaleness? It would also decrease binding. Since it may be hard to describe this in text, here's a picture of what i'm talking about...
http://i35.photobucket.com/albums/d1...5/long-arm.jpg
If i had the money and skills to build a sweet rig like some of yall's, i would deffinately do this. If anyone would like a more detailed or different angle of this picture, let me know.

P.S. - I posted this in the scale section because it seems like something that would give a rig (especially a wrangler) a nice scale/realistic touch.

That's kinda like a 3-link, except the top part isn't integrated.

I've tried it, but it didn't work too good. The rod ends on the lower links moved too much, which allowed the axles to move side to side. Triangulation wasn't the problem either, I had plenty built in to both the upper and lower links.

most 3-links i've seen here mount the upper control arms to the frame too... maybe i did miss some.

most of those kits run a track bar and only have pivot balls (heims at one end) they also dont triangulate at all, the track bar keeps it all centered

It is not a 4-link set up. It would have to use a trac-bar to center it. It is also a very similar set up to a front Ford radius arm set up, which many consider a 2-link (depending on whether you want to call a lateral bar a link).



btw, I am in the process of designing my scale EB right now, which will use a similar set up on the front

I think it would be pretty cool for a scale rig, just integrate a panhard bar.

http://www.rubiconexpress.com/dynami...p?folderid=185
read the 2nd kit down's description. 5.5" Long arm kit. Deffinately a 4-link. the control arms mount in 4 places on the axle unlike a 3-link that mounts in one spot above the axle and the 2 lower links. This kit isn't that great of a long-arm kit, but it's the design that i'm talking about. Yes it uses a trac-bar to center it mainly because it has a coil sprung suspension.

yeah i understand what you are saying its not a true four link.... anyway coil springs and coilovers like we use still have to be controled with a track bar....

That's a ladder bar suspension. A 4 link is suppose to keep the pinion angle right throughout the suspension cycle.
The ladder bar the pinion angle is fixed and changes angle while cycling the suspension.

could you explain that a little more? I'm trying to picture the differences in my head, but the differences in where the upper links are mounted frame side (as in not to the axle) are not registering a difference in pinion angles :x. It seems to me that it's the opposite of what you're saying... but I know i'm wrong... please explain...

Here are some simple drawings.
The first the four link. The pinion angle dose not change through out the entire suspension cycle.
The second is the ladder bar. The pinion angle is fixed makeing it change as the suspension cycles. When it dropes the pinion is pointing upward. The compress the suspension past horizontal and it's pointing towards the ground.

i dont get it ??
is it good for crawling ?

Crawling it doesn't matter. You will only notice a differance at 80mph hitting bumps and jumps.

Wow, when i clicked back on this thread to read your response, it clicked to me before i got down to your post. Thank you though, those pics do explain it well. Are there any real disadvantages to running this "ladder bar" suspension as opposed to a true 4-link that would make it not worth trying? I figured if it worked for jeeps in real life, it would work in R/C. Reason being it eliminates 2 links to the frame to interfere with axle twisting/ traveling. But i guess this may be one of those things that doesn't translate precisely into the r/c world from real life. :-(

the pinion angle doesnt change as much as the caster angle changes... there is a big change in caster angle as the long arm style kit travels... that is the important difference....

Yeah didn't someone try this already? I think they lost most of their flex???? Uhhmmmm not sure?:-(

does it matter if say the right link is an iunch in from the frame rail but the left one is and inch and a half or so from the frame rail.




cause on the truck im working on the mounts for shocks adn the links cant be ?symetrical?? i think is the word . because on the left side the drive shaft goes right where the right side link will be
http://i22.photobucket.com/albums/b3.../jun04_004.jpghttp://i22.photobucket.com/albums/b3.../jun04_003.jpg

It should not make much of a differance on it. It would be best to just mount them the same though.

that would make a big difference... the geometry of the front end will limit travel on one side..