I dont know why. And do some reading about the geometry for them.
Designing And Tuning The 4 Link Rear Suspension
3 link suspension vs 4 link. Even the heims are all still original. Most guys dont need that much adjustability. Poor front or rear geometry on a link suspension will make cornering exciting and emergency handling downright dangerous. Theres no better method to setting the roll center height and keeping an axle laterally constrained than a track bar period. 4 an item that may not be a large factor but still should be considered is at full suspension droop. 3 the 3 link is part of a sway bar system and putting a 4 link on a truck that came with a 3 link will require a bigger sway bar because there will be more body roll.
They are simple to a fault. All too often track bars are made out to be an enemy and thats just not the case. The 3 link setups will have more side to side axle movement than the 4 link setup. He didnt say triangulated 4 link but did say he was looking for lateral control so im assuming he was thinking parallel bar 4 link. I researched a full year on pirate4x4 prior to tackling my rear 4 link suspension on my fj40. I still run the 3 link on my mostly stock scx10 with no problems but on my dual motor rig the 3 link just had way to much movement.
And as far as the parallel 4 link goes yer right they have been mostly geared towards the drag cars or pro street trucks and cars. The articulation will also be smoother with the 4 link. 3 link rears are very cool and if executed correctly will perform even better than a triangulated 4 link. It got one minor adjustment but has largely worked. A 4 link suspension is geared for adjustability. You will also get axle twisting more with the 3 link.
And to get that you need some tall brackets. A 3 link will be fine just gotta make sure its really stout for the upper link and mounts.
Gallery of 3 Link Suspension Vs 4 Link
