View Full Version : Cooking up a BB Lift.... Questions

March 29th, 2005, 13:53
So I've got half of a Procomp 2.5-3" lift.. The rear half including the shocks and the add a leaf.

It looks like it uses a partial length add-a-leaf for the lift judging from the website I'll double check the leaf pack sitting in my garage after work... the leaf pack I grabbed from the yard is off a 2000 XJ... Instead of separating the leafs I just grabbed the whole pack figuring newer leafs is always a good thing.


Now I'd like to install the rear lift and match the height in the front with some bits from ?????

I have a few questions before I decide how I will do this.


Add a leaf rear lifts tend to make the rear stiffer and flex less because they achieve the lift by increasing the spring rate. For the price I can hardly complain about that..

1.) Do add a leaf lifts contribute to causing the stock leaf pack to sag? remember I am using a leaf pack froma 2000 not my old 91's (which are actually not sagging at all at stock ride height)

2.) Any other downsides associated with a partial length add a leaf i should consider?

3.) In my searches I found ProComp Budget lifts are known to sag in the rear.. How much? any related damage to other components?

4.) I will be running 29-30" tires for the time being.. stock wheels. I suspect there won't be any rubbing since there isn't any now... confirm?


For the front I'd like to just get some cheapo spacers from Rustys or RRO

1.) Do you think I'll need more than a 2" lift for the front to match the rear? rusty's had 1.75" spacers and .25 Spacers so I could get a few extras so I can adjust to match my rear sag.

2.) Will the difference in front and rear spring rates make the nose dive worse than stock? Is the handling bad enough that I would be better off getting stiffer front coil springs for the front 2" lift?


Alternatively I could call the AAL Rear I got at the yard a 25$ loss and pick up the RRO complete kit for similar results and more $$ invested...

Honestly I'd rather spend my money on a set of Tomkin Front tow hooks and brackets and a D Shackle for my rear reciever hitch.. but if it's going to handle all scary with the AAL in the rear and stock coils and spacer in the front... money spent on the RRO Kit would be WELL spent as this is my DD..

I did alot of searching so far and will keep it up..

any info on procomp rear AAL sag, and road handling on BB lifts using front coil spacers and AAL in the rear would be highly appreciated...

March 29th, 2005, 14:14
I lot of people use spacers and AAL to lift their vehicles and I can't see why it will affect the handling of your XJ much. I'm not sure about the Procomp AAL but I had a Trailmaster one in my XJ (from the 4" lift) and it did stiffen up the ride, ALOT. The other problem I had was that since the AAL was increasing the spring rate of the rear pack after about a year of wheeling hard my rear springs were beginning to be bent, and right now I'm in the process of putting new leafs in. If you're only looking for a BB maybe you want to look into the traditional spacer and shackle kits available from almost everyone. Just my .02

March 29th, 2005, 14:24
I guess my concern on the handling is the AAL will be alot stiffer than a stock rear leak pack

The front with the poly spacer will have the same spring rate but still be taller..

This would mean more leverage on the front springs from the height increase but the same spring rate..... I would think that would cause more front body roll and nose dive under braking than a longer, stiffer front coil from someplace like rustys....etc.

EDIT:: Alternatively it should allow a softer front spring for more flex... (probably uneven with the rear though)

March 29th, 2005, 16:23
Just lifted mine with ZJ front coils (Carquest CC784's) got 2 1/2" out of em, supposively they are about $70 in the US paid $135 Canadian for em, sweet ride out of then also. The rear has thus far been alot of trail and error to find the right lift height with the various leafs i have available to me. Cosodering the cost of a set of spacers and that you have to take the coil springs out to put in the spacer......seriously consider new springs