ntsqd
heratic car camper
There is an important yet not often considered aspect worth thinking about. Drive-shaft plunge. Where the frame pivot is placed can have a very large influence on plunge. The most ideal location (with regard to just this aspect) would result in no plunge or extension of the drive-shaft thru the whole travel range. The lone desert racing rear 4 link that I've designed had this as a high priority concern from the team owner. He wanted no plunge/extension in 24" of wheel travel.
There's a couple reasons why this is important.
Ride quality at road speeds will suffer with excessive plunge because it is a resistance to movement. Makes the suspension ride that much harsher.
Articulation under power will also suffer for the same reason, even though they're designed to move under load they are not friction-free under load and the further they have to move the longer it will take, which will slow down the axle's movement.
And that's not to mention what those plunge-extend loads do to the U-Joints and output shaft bearings. To give an idea of the size of those loads I have seen a drive-shaft that would hydro-lock at desert speeds. It tore up the transmission in less than 100 miles. There were two causes, the primary was way too much grease in the slip-yoke (& a welded weep hole to keep dirt out) and the second was a suspension that required about 6" of plunge travel in the drive-shaft.
There's a couple reasons why this is important.
Ride quality at road speeds will suffer with excessive plunge because it is a resistance to movement. Makes the suspension ride that much harsher.
Articulation under power will also suffer for the same reason, even though they're designed to move under load they are not friction-free under load and the further they have to move the longer it will take, which will slow down the axle's movement.
And that's not to mention what those plunge-extend loads do to the U-Joints and output shaft bearings. To give an idea of the size of those loads I have seen a drive-shaft that would hydro-lock at desert speeds. It tore up the transmission in less than 100 miles. There were two causes, the primary was way too much grease in the slip-yoke (& a welded weep hole to keep dirt out) and the second was a suspension that required about 6" of plunge travel in the drive-shaft.