planman

The axle travels in an arc as it articulates.

A really long upper front extended bumpstop is more likely to get caught in the spring as the spring bows. Also, installing front lowers helps with spring retention if your shocks are slightly long.

For the rear, the primary reason is that it is just easier to bolt an extension to the lower pads on the axle. There are already holes available for bolts.

Finally, the longer the upper extension, the more susseptible it is to damage from leverage.

FreedomJeep13

Man Great write up and a Great read. Thx for taking the time to put this info out. I've will wind up reading this more than once. Thx again!!!

GJeep

When someone agrees with most of what you said, but points to exceptions to your "rules", using logic could have been a better reaction than getting nasty.

I've offroaded Jeeps, and quite a few of other 4x4s, including H1 and larger. Add tactical driving, and some dirt road rallying -- enough to have a pretty good feel of a vehicle.

When I compared the stock Rubicon to its' later behavior with 4" lift and 35"s, there were only 2 things I didn't try. One is snow, the other is getting to the verge of flipping sideways.
Except for these two which I didn't try, the 4" lifted Rubi with 35"s behaves quite better than the stock, in spite of its' higher COG.

"Throw those same 35's on a stock suspension with trimmed fenders and everything I said would still be true" -- That would have kept the stock suspension, with which the Jeep didn't behave as good as with the lift...

If side slopes are the only case where the lifted Rubi is somewhat inferior vs a lower lift, the improvement in every other aspect covers for it.
The whole difference between 4" and 2.5" lift is just 1.5", which isn't much anyway, and can't make a dramatic difference.
On the other hand, there were reasons to take 35" and not 37", such as avoiding re-gearing and strengthening of some parts, and avoiding the higher stresses on the steering system and the brakes.

My point is simple: You don't need to become nasty if someone agrees with most of what you say but not all.
You laid it out very nicely, offered an excellent direction to many, and saved them money on the way.
However, it is not necessarily the only way to improve the Jeeps' capabilities, without compromising its' behavior, and even improving it.
A good 4" lift with 35"s, the right coil/shock combination, and proper tuning of the suspension, can result in very good on & off road behavior, and the added 1.5" (from 2.5" to 4" lift) isn't enough to wash off other benefits.

planman

GJeep,

Anecdotal experience doesn't change physical science, physics, and geometry.

Control arm angles and geometry change center of gravity, squat/anti-squat, brake dive, traction on steep climbs and off-camber situations, etc.

There is a good amount of great information on the subject on pirate4x4.com, along with a calculator for people who are making custom length links (control arms) and mounting points.

A jeep with 12" travel shocks with 2.5" dual or progressive rate springs that can handle the shock length, with the minimum bumpstopping required to prevent the shocks from bottoming out, and control arms with flex joints or heims, using stock control arm mounting points will outperform a jeep with a 4" short arm, 10" travel shocks, using stock mounting points, with 4" extended bumpstops--all other things being equal (ie tires).

The less steep angles will allow the lower lifted jeep to keep better traction on steep climbs and decents, and through off camber situations.

The less steep angles on the lower lifted jeep will have less brake dive on hard stops. It will corner better also.

It will have more traction off-road because the suspension will articulate better and keep the tires on the terrain.

There will be less axle wrap on steep climbs.

Anecdotally, this might not change the trails and obstacles you chose to do, but it would increase the finesse and ease with which you do them.

These are the kinds of points we were meaning to make here. Not beat people up.

ABENDX

GJeep... DIRTMAN's (and PLANMAN's) advice and write up is sound; furthermore, it goes a long way to stopping the "what lift" type of posts (if he could only figure out how to squash the "what color" threads).

Sure, you are right that there is usually more ways than one to skin a cat. Sometimes the wrong way will actually work. DIRTMAN is attempting to spell out the right way to do things within the limits he set and giving specific JK advice. I certainly wish this was out there when I started with my JK. I'd have saved a ton, probably gone through less rebuilding, and would have understood quite a bit much sooner than it took me to figure it out on my own.

Mad Dog 21

Wow, great info for a boot. Thanks for all the info that I wasn't sure about.

espi

Thank you for this write up. I am currently running 285/70/17 duratracs and want to add a front bumper and winch about 200lbs. My question is should I get a leveling kit or a 2.5" lift? I was looking at the Eibach Leveling Lift Kit or the AEV 2.5" lift. This is my DD and I don't do any rocks mostly trails and beach. The max tire size I would go up to is a 285/75/17. I am leaning toward the leveling kit to offset the bumper and winch and give a small lift.

planman

You will want stiffer front springs, not a coil spacer solution or a typical leveling kit that uses front coils.

The AEV coils usually are designed to be able to handle heavy AEV bumpers.

jadmt

After reading most of this I think I am happy with my choice. I went with AEV 2" kit, I have stock bumpers and will probably stay stock bumpers for a while. I am going to go with a lighter winch with synthetic line so no more then about 60-70lbs. My 120lb daughter sat on the bumper and it sagged by about 1/4" is all and with my 200lbs about 1/2". It has stock 18 springs up front and 60's in rear. I have plenty of room if I decide to go from 33's to 34's on tires. I enjoy the power of the 33's with the 4.10's tho.
thanks for all the great info.

espi

Thanks Planman,

The leveling kit I was looking says it uses progressive springs and not spacers. I figured it would be more like the AEV progressive springs and handle the extra weight. I have a 4 door and with my stock setup 17 & 58 Springs when I stand on my front bumper around 200lbs It drops 1" and the front is already 1" lower than the back. I like the idea of spending less money as it keeps the wife happy and more money for other upgrades.

Espi