The heavier the arch in the leaf spring the worse the spring rate is going to be, flatter leafs just flex better. Spring over usually flexes very well because it uses less arched leafs but requires a lot of fab. work. Not only do you have to flip the perches, steering geometry needs to be corrected, axle rap needs to be adressed... ETC. The beauty of a bolt on kit is all the engineering has been done for you. A bolt on kit will have all the new brackets and extension pieces need to get the jeep to handle properly. If you are not good at fabricating parts I would suggest a bolt on spring under kit. If you are good fabricator, go spring over. I feel if you are going to go spring over, you might as well go one step further and convert to coil springs. Coil springs are a lot more linear than leaf springs, so the ride is very good and because the suspension must be link axle wrap is eliminated.

Going to coils was actually a thought but I think if I do it'll only be in the front. The fab work is the least of my worries. The jeep is down to the frame right now, and I've been welding reinforcements in and fabbing up new mounts for everything. My goal before assembly was to make sure that nothing was left to hangup under the chassis. It all flows now. As for the axles, if I were to coil the front how do I match up the coils to a spring over rear? Or will I have to fab that too?

i would do a spring over front and coils in the back. there's alot of stuff up front to try to build a link suspension around. your big gain with the coils in the back is departure angle and maybe a little wheelbase stretch if you choose to build it in which would give you a longer rear driveshaft. for some, the extra wheelbase is useful and/or necessary for the trails they run. a front link suspension will gain you little over leafs for approach angle if you have a winch and bumper on the front. my approach angle with an 8274 tucked tight against the grill and a bumper to mount it to is about 68 degrees to the bottom of the bumper. my shackles are forward of the bumper a little bit so my actual approach angle is only 60*. if i ran stock yj leafs instead of offset waggy's, they would mount behind the bumper and and not hinder my approach angle compared to coils. leaf springs are simple and hard to screw up.



rear shackle length or coil spacers, whatever works. keep in mind that a rear spring over WILL require a traction link to minimize/eliminate spring wrap with flat, soft springs like stock yj's.

there are positives with leafs in the rear also the main one being handling characteristics both on and off the trial.

Coils are vastly superior to leafs. The only reason I see to run leafs is simplicity and low cost.

With leafs the spring does both the locating of the axle and the supporting of it. Also the way the spring is set up the travel is not linear. Since the thing that is locating the axle is a spring it can change shape easily, axle wrap. If you make a ladder bar to control axle wrap, it usually binds up somewhere. Also youÆll be linking the suspension so you are fairly close to being able to run coil springs.

Coil springs only hold up the axle, the control arms locate it. Because the locating arms are not made of a spring material and are very firm, no axle wrap. You can also design the geometry whichever way you want. You can keep the caster near the same through the whole range of travel, or keep the pinion pointed at whatever you want. The spring design allows for a very linear spring. Also instead of adding more arch to get more lift you just add more coils. By adding more coils you arenÆt changing the shape so you get more height with about the same linearity.