Matt16

Could someone explain to me roll centre in relation to the panhard rod. Some literature suggests you want to lower your roll centre, but this doesn't fully make sense to me. Something just isn't quite clicking for me.

abecedarian

if you think of the roll center as the longitudinal center of gravity it may make more sense. though not technically correct... if you went around a corner at speed, it would be the point / axis around which the vehicle could be seen to 'pivot' on when leaning.

Hypoid

Lowering your roll center is good, but keep in mind we drive trucks, not sports cars. Handling was compromised in tradeoff for many things in the design phase.

The above picture does show the correct way to find the roll center in a live axle suspension.

Your school library may have a copy of Milliken & Milliken's "Race Car Vehicle Dynamics". Most of the text is spent with independent suspension, but there is some beam type axle info there too. There are other texts available that I can't comment on, but "chassis setup" "vehicle dynamics" and such are good search terms.

You probably know this, but if you change the ride height of a vehicle equipped with (a) panhard(s), the panhard either needs to be lengthened or one of the mounting points changed (frame mount dropped) as the panhard is usually set at or nearly at horizontal from the factory. Without, the whole axle will be offset from the chassis at ride height.

Matt16

Next question is whether a panhard drop which would lower the roll centre maybe 2" would be noticeable of if it is a waste of money with this angle panhard?

tc

Well, the way I understand it, the roll center is the average height of the two pivot points for the panhard bar (interestingly, regardless of the other links). The roll center is what makes the vehicle feel tippy. Lowering my roll center 2 or 3 inches has resulted in a significantly more stable vehicle IMHO.

The other thing to consider with a panhard bar is the side-to-side motion of the axle as it articulates. The more level the panhard bar, the less this is a problem.

I guess that is a long way of explaining that a panhard drop bracket would be money well spent.

Matt16

Interesting. I will look into getting one. Prior to now, I assumed as long as you weren't hitting the gas tank with the DS, you didn't need a panhard drop.