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Author Topic:   4/2 vs. Swingarm 2
Dirt Roller

Total posts: 14
posted October 25, 2005 09:51 PM  
I am looking at changing my 3 link over to 4 on LR and 2Link on RR or doing Swing (no z-link) on LR and 2 link RR. I run a metric front with 750# Rf and a 650 or 700 LF. What spring rates would you guys run on rear. I will be racing 3 tracks next year. A big 3/8 high bank that gets slick quick, a 1/4 banked thats stays pretty tacky, and a big fast 1/2 thats stays pretty good. I plan on messing with the front roll center too. Any help would be great. If I do the 4 link on the LR I will only be floating the links and not the shock or slider.

Dirt Forum Champ
Total posts: 753
posted October 25, 2005 10:14 PM  
Man, your racing on about every different type of track there is, aren't ya' LOL!

I run the 4-2 but I've never ran a swing-arm so I can't help you much with the swingarm. But if you run the 4-2..... you might find that with the LR spring clamped up front the car will be too tight on exit and too erratic. I say that because the 4-2 really increases the forward bite and tightens the car a good bit. But you can try it and see how it does. Your panhard bar also has a lot to do with how erratic the car will be, are you running a j-bar, shorty bar or long bar??? If you decide to float the LR on the cage behind the axle then start with rear springs: 225 LR 200RR if you clamp the LR spring then increase its rate to 250 on the LR and 200 RR.

Now as for the front roll center. Do you know where it is now?? And where are you planning on putting it? 3-4" above ground and 3-4" left of centerline is usually a good starting point. But on higher banked tracks the r/c can be further to the right due to the increased downforce of the banking. So when you map out the r/c and place the upper arm pivot points, I recommend that you install brackets with at least two holes in them. Meaning one hole on top of the other so that you can raise/lower the upper arm pivot points. That way you can change the r/c easily between different tracks if neccesary. By having the LF pivot lower than the RF it will move the r/c further left. And vice-versa.

Hope that helps!!

Dirt Roller

Total posts: 14
posted October 25, 2005 10:23 PM  
I am running a short panhard bar around 12". I have 14" trailing arm on right and 12" on left. I don't know where the front roll center is right now so I will check it first.
Thanks for your help.

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