There have recently been some confusing discussions regarding the effect of variations of the Coupling Load, on tandem-axle 'vans, depending on whether the suspension system is Load-Sharing or NON-Load-Sharing.
With "Load-Sharing (Tandem-Axle) Suspensions" the Ball-Loading stays virtually the SAME, regardless of the height of the Coupling.
With "NON-Load-Sharing (Tandem-Axle) Suspensions" the Ball-Loading VARIES with the HEIGHT of the Coupling above the ground.
RAISING the height of the Coupling will INCREASE the Ball-Loading.
LOWERING the height of the Coupling will DECREASE the Ball-Loading.
On a typical caravan with an ATM Rating of 2,500 kg - and with an Empty Ball-Loading of around 250 kg - the Ball-Loading will vary by around 30 to 40 kg - in the corresponding direction - when the height is varied by around 80 mm, in each direction.
A caravan with a NON-Load-Sharing Suspension system, should be LEVEL (in a side view), so that ALL wheels / tyres have an EQUAL loading.
There have recently been some confusing discussions regarding the effect of variations of the Coupling Load, on tandem-axle 'vans, depending on whether the suspension system is Load-Sharing or NON-Load-Sharing.
With "Load-Sharing (Tandem-Axle) Suspensions" the Ball-Loading stays virtually the SAME, regardless of the height of the Coupling.
With "NON-Load-Sharing (Tandem-Axle) Suspensions" the Ball-Loading VARIES with the HEIGHT of the Coupling above the ground.
RAISING the height of the Coupling will INCREASE the Ball-Loading.
LOWERING the height of the Coupling will DECREASE the Ball-Loading.
On a typical caravan with an ATM Rating of 2,500 kg - and with an Empty Ball-Loading of around 250 kg - the Ball-Loading will vary by around 30 to 40 kg - in the corresponding direction - when the height is varied by around 80 mm, in each direction.
A caravan with a NON-Load-Sharing Suspension system, should be LEVEL (in a side view), so that ALL wheels / tyres have an EQUAL loading.
Hi Possum...interesting post,with lots of good information! It also should be noted that,in addition to it being critical that a non-load sharing suspension van be level,it is equally important that the tyres on the front axle of such a suspension be run at a lower pressure than that in the tyres on the rear axle of such a suspension.Usually 3 to 5psi lower is sufficient,but the lower pressure allows the tyres on the front axle to shuffle. If this is not done,the van is more likely to pivot on its front axle,thus effectively increasing rear ovehang,encouraging yaw,and making the van far more unstable.Cheers
Hi Possum...interesting post,with lots of good information! It also should be noted that,in addition to it being critical that a non-load sharing suspension van be level,it is equally important that the tyres on the front axle of such a suspension be run at a lower pressure than that in the tyres on the rear axle of such a suspension.Usually 3 to 5psi lower is sufficient,but the lower pressure allows the tyres on the front axle to shuffle. If this is not done,the van is more likely to pivot on its front axle,thus effectively increasing rear ovehang,encouraging yaw,and making the van far more unstable.Cheers