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View Full Version : panhard bar length?



ashurst21
03-26-2011, 03:18 PM
the new rules we have to run require 20 trailing arms min 20 solid pull bar max 20 panhard bar min behind the axel. i know you have to have a longer panhard bar then your trailing arms to achieve the bite you want. we used to have 15 on the left and a j-bar 22 3/4 so whats the magic formula to figure out what size panhard bar i need?

Dirtrunner35
03-27-2011, 07:44 PM
I know you have to have a longer panhard bar than your trailing arms to achieve the bite you want. Who says this ?

ashurst21
03-28-2011, 12:24 AM
i read that some where on here, are you saying that it isnt true if so enlighten me i wanna know what the magic number would be. 20'' trailing arms 20'' solid top link and a min 20'' rear mounted panhard bar. i am sure there is some formula to figure out the correct length.

bushracing67
03-28-2011, 09:07 AM
i believe when the bar is mounted behind the rear you want to make it as long as possible to slow down the gain of angle, j-bar/straight bar mounted in front is normally shorter so that it reacts quicker to losing angle

my first car was a truck arm and i had no idea what the hell i was doing at the time, but my panhard mount on the rear broke and i had made new mounts that took the bar from the left frame rail to about as low
(3-4" below the bottom of the axle tube) and as far right (about touching the rotor) as i could get on the rear end and it worked way better than the old mount which was higher and in a bit from the right tire

propit21
03-28-2011, 10:13 AM
also on the same subject by moving the panhard bar to behind the rear in its also going to move the rear roll center back in the car, when doing this is there going to be a noticable wieght tranfer feel or is it all going to be the same.

hogracer3d
03-28-2011, 08:16 PM
Who in the he'll would have a stupid rule like that? Lol

The AFCO tech pages, have a plethora of information, I hear

propit21
03-28-2011, 10:54 PM
don't know, must have been a leaf spring guy... how the car coming also you wouldn't have any pic of you rear panhard bar would you?

hogracer3d
03-29-2011, 07:53 AM
No pics that show it very well,but I can tell you it's right on the minimum, at just over 20", and that we made to mimic a J-bars pick-up points.

We can't really tell any difference between it and the front mounted old J - bar

Our lowers ( stock A body GM) are about 22-1/2"

propit21
03-29-2011, 01:32 PM
we are trying to do the same, for the panhard bar keep it the same as our j-bar, we were thinking about throwing the j-bar on the back for fun and see what they say, it would just show how much they really understand.
we already got our 20 inch swedge trailing arms in place and they are right at the min of 20 inches except for the right being 20.5 inches to get it where we need it. all we need now is to finish up the panhard bar mount on the rearend and get the soild upper in place and we are wcss legal for now. haha

we plan on racing this weekend over in az and going to try a bunch of test stuff and see how it all goes.going to be messing around with springs/shocks/ angles and setup stuff to be ready to run with you big boys up in sms. i think we might do the nationals to.

hogracer3d
03-29-2011, 05:14 PM
Big Boys hell, you won the Turkey..............

propit21
03-29-2011, 06:47 PM
you guys won the nationals and the turkey and everything in between haha

Dirtrunner35
04-02-2011, 09:06 PM
It would be too hard to put a longer bar in front of the axle, so that's why it's in the back. A longer bar has the rear roll center more in the middle of the car and has a lower roll center, depends on how it's mounted. Also, less weight transfer. I tried it both ways and always like the j-bar in front. I went to a short bar and liked it better than a j-bar. The short bar had the roll center even lower than the j-bar.

With the RR trailing arm longer, it limits the rear steer even more over a shorter arm.