Roll centers using 4 link rear, 3 link & panard front

[AFeral]

Currently helping a friend build his suzuki Sierra buggy. For the rear we have built a dual triangulated 4 link. For the front we are building a 3 link with panard, ie two lowers one upper and the panard. Heres what i know for the rear, correct me if i'm wrong please.
Hieght distance between the lower and upper link points on the diff should be approx 1/4 of the tyre size.
Lower links on the chassis should be mounted as low as possible.
The hieght of the upper link brackets for the chassis control the pro-anti squat. We've made that adjustable.

For the front ?
Lower links are the same length as the rears and run parrellel too the chasssis.
The upper link is the same length as the one of the rears again running parrellel too the chassis.
The height differance on the diff between upper and lower links is the same as the rear 1/4 of the tyre size.
The upper chassis link point is adjustable too.

Been trying to fit the panard on the front. My understanding is the panard should be mounted the same hieght above the diff as the rear rear upper links. This would keep the roll centers the same on the front and rear ? Is this correct. Or can I just mount it lower on the diff making it a lot easyer to fit ?

Thanks for any input or correction of my suspention knowage.

[Giggles83]

Pretty sure theres a 3 link calculator as well

[TheBigBoy]

Its not so much the height above your diff. Its more the angle and length of your panhards. You can drop your panhard within reason, solong as the angle from point to point (front and back) are the same. But a 3 link front is very forgiving, its not like a 5 link.

Here check this out... And the ratio's
http://www.actionjackson.com/cruiser/mods/20060110.asp" onclick="window.open(this.href);return false;

Hope this helps

Even at 70.5% with a 3 link front. The castor is correct at drive height. Its just works like a roller coaster ride for your caster during the suspension cycle

[foxracing_is]

There is nothing to say that your vertical separation on the axle end should be approx 1/4 of the tyre size. What you can say is that the less separation; the more force is applied to the suspension components.
Personally I run as much vertical separation as I can while still keeping my pinion angle, anti-squat, roll-center, axle recession, and bump travel where I want them.
Summary: Less vertical separation requires stronger components.

I'll take the next two together.
'Lower links on the chassis should be mounted as low as possible.'
'The height of the upper link brackets for the chassis control pro-anti squat.'
Lower links should only be mounted as low as possible if that gives you the desired suspension geometry.
Your anti-squat is controlled by both link angle (uppers and lowers) and the theoretical convergence point of the upper and lower links.
Example A: A vehicle with 8" vertical separation on BOTH the chassis and axle side would be considered to have 0% anti-squat; IF the arms were parallel to the ground (this is wrong. but it is the easiest way to make you understand).
Example B: A vehicle with 8" vertical separation at the axle and only 6" separation at the chassis may actually have a LOWER static anti-squat % than example A; IF Example A's control arms were at a larger angle (who knows how much larger) when anti-squat is measured.

In regards to your Panhard question. I think the answer is 'no'.
IF you want your roll centers to be the same at a static height you will need to place the vertical center of your panhard at the same height as your rear roll center. If you place the axle side panhard mount at the same height as your roll center you will most likely end up with a higher front roll center; unless your chassis side panhard mount is lower than your axle side panhard mount and can place the vertical center of the panhard at the same height as your rear roll center.

[uninformed]

keep the RC the same front and rear is a matter of choice. For example, Landrovers have a higher rear RC where as a Nissan has a lower Rear. May have something to do with the COG above the particular RC....in a speed type situation and Lower front than rear, will make the chassis "Loose" with the rear tending to let go first.... RC will also change the suspenion to body movement ratio and stability on side slopes etc. RC for a Panhard is the intersection of it through the chassis centerline when viewd from the front.

Anti squat or anti dive in the front is not only the link geometry but involes the COG and wheelbase....Anti dive also has front to rear brake bias involved....

[want33s]

Can anyone say if the panhard HAS to be parallel to the front axle or is it possible to have it at an angle to the diff housing....
IE: The diff end of the panhard further to the rear than the chassis end.
What difference (if any) will it make?

We could run it parallel but it would require a bend and we don't want to do that as we'd like to keep all three upper links and the panhard the same so I only have to carry one spare upper and one spare lower link arms.

[foxracing_is]

It can be at an angle.
Ideally your Panhard bar should be perpendicular (90* angle) to your control arms, when viewed from above looking down.

Basically don't put it at 'too much' of an angle.