does the panhard bar angle affect handling?

[351ciofgrunt]

Got a GQ that has been raised and was just wondering if it would handle better if the panhard bar was brought back to level, either by raising the mount on the diff or lowering the mount to the body?

[PGS 4WD]

They bump steer more as the arm flattens under compression and shifts the body centreline in relation to the diff centreline.

Cheers

Joel

[lay80n]

The panhard rod height also effects the roll centre. The roll centre is roughly the centre of the panhard rod. Bump steer will only happen if the angle of the panhard and the angle of the drag link are different.

Layto....

[Gwagensteve]

Which means that lowering the chassis end lowers roll centre, and raising the axle end raises roll centre.

[PGS 4WD]

The panhard rod height also effects the roll centre. The roll centre is roughly the centre of the panhard rod. Bump steer will only happen if the angle of the panhard and the angle of the drag link are different.

Layto....

Unfortunatly even with stock angles the pan hard and steering arm don't run parallel as the mount points are not directly vertical above each other.. the angle between the arms must vary due to this even though they are parallel when horizontal at stock height.

You need to imagine as the pan hard angle increases due to lift the steering arm becomes effectivley shorter (horizontally) causing the front wheels to deviate (right with lift, left with compression until the arm is again horizontal), the angle of the pan hard in relation to the steering arm dosen't stop this, get into a shorty with a 3" lift, hold the steering straight and drive at a reasonable speed over speed humps, the car goes left under compression and right under lift provided the steering arm dosent move from the straight ahead position. This is why we need adjustable pan hard rods in lifted vehicles to centralize the body over the diffs. It feels more pronounced with a shorter wheel base.

Cheers

Joel

[65Mog]

I've got a GQ with a 3 inch lift and the chassis panhard mounts have been lowered 3 inches, I was also going to fit a GU steering box and reverse the taper in the pitman arm to lower the steering as well, but I didn't notice any difference in how it steered so I never worried about it. I'll get around to it one day, but only when the standard steering box is worn out.
The flatter you get the Panhard bars the better they drive, there's no doubt about that.

[Hobzee]

Joel is onto it ...

But wait , there's more - imagine in a perfect world a panhard is dead level. Exert a sideways force (the job of a panhard) and the tendancy is to stay level. But lift one end and get say a 15 degree slope and then exert that same sideways force - the tendancy is for the high end to go higher and create a steeper angle. When cornering your 3" lift can become a 5" lift without noticing. The steering arms get shorter and steering is affected, not to mention shocks topping out that were already a bit too short in a 3" lift, rear wheel steer with the back diff shifting sideways, etc etc.

In a perfect world panhards need to be always level.

If you lower the chassis mount watch you dont twist the chassis under load so cross brace it to the other side for anti twist strength. But then note your panhard is lower to the ground and may snag. May be better to lift the diff mount but then watch for clearance on floor, fuel tanks and exhaust, etc. This really ought to be then engineered ..