Axle over leafs vs axle under leafs

Just a general question on pros, cons, reasons to have one setup over the other.

I've noticed certain vehicles have the leafs over the axle (tacoma for one obviously, and other pickups), and I've also noticed vechicles like a Nissan Xterra has the axel over the leafs. I'm sure there are more vehicles like that, but there is always one on my street that I tend to notice everyday.

I've also noticed that MPJ2's build has his new leaf pack going under the axle (nice build btw, very impressive!). Granted he's got a specific purpose for the components in his setup.


So I'm curious what makes an axle under leaf setup good, and when/why would you get an axle over leaf setup.

John

 

The main reason - being spring UNDER axle greatly reduces axle wrap.

Although - the rear suspension isn't nearly as critical as a vehicle having spring under in the front (for those with solid axles up front).

Early Jeep Wranglers were spring under axle from the factory - front & rear.

Overall - the suspension flex (for offroad) isn't as good with spring under axle as it is with spring over axle. This is a huge debate in the Jeep Offroading world.

With my own Jeep build, we swapped out the axles and stayed spring under the axle - because the overall drivability and controllability (steering, allignment, death wobble, etc) is MUCH better when your spring under. My jeep has 35's (6" lift) and we can drive it on the highway at 70mph without any problems. Most offroading Jeepers convert to Spring-Over axle because it gives such huge flexibility for offroading. But - at the same time, they loose some drivability/controllability. Any setup can be fine tuned to work to your expectations. It all depends on what you're looking to do with it.

In terms of Toyotas/Tacomas - I wouldn't bother wasting the time/money to go SUA on a SOA tacoma. I personally don't think the benefits would out-weigh the cost & effort to do it. But that's me.

 

Excellent info. Thanks for the explanation. I'm certainly not changing my Tacoma, I'm just wondering the thought process between the different setups that I see on different vehicles.

Thanks for the insight!