Hi guys,

Anyone here install an add-a-leaf to the rear of their X? My X is lifted and I have 6" of blocks in the rear. I'm trying to minimize the block height. I found a set that claims 2.5" of added height but I figure with the weight of the X you'd be lucky to get 1.5". Another twist is I'm looking into some B codes for the rear which I read will increase ride height about 1". So, B codes and 1.5" of add-a-leaf may net me a max of 2.5"...I'd be stoked if I could reduce my block height from 6" to 3" or so.

Comments???

SW

 

I would think about getting the B's re-arched and either eliminate the block or go to a stock 2". I've got a set of A's to go on when the X can sit still for a couple of days and it's no 30* out. The B's also have a softer spring rate than the stockers.

2001 Excursion
SPRING SPECIFICATIONS — REAR LEAF

Series/Model Combined Rating @ Ground (lbs.) Number of Leaves Total Thickness @ Pad (in.) Length (in.) Width (in.) Deflection
Rate (lbs. per
in./ spring) Rating Each @ Pad (lbs. per spring)
4x2 5250 6 2.5 58.08 3.00 410 2275
4x4 5250 7 (1) 3.16 58.08 3.00 410 2275
(1) 7th leaf is an anti-windup leaf.

2002 F-250
SPRING SPECIFICATIONS — REAR LEAF
Super Duty Series/Model Combined Rating @Ground (lbs.) Number of Leaves Total Thickness @ Pad (in.) Length (in.) Width (in.) Deflection Rate (lbs. per in./ spring)(1) Rating Each @ Pad (lbs. per spring)
Main Leaf Only (Refer To Auxiliary Spring Charts Below)
F-250-350 SRW Pickup 6830 5 2.94 58.1 3.00 320/670 2998
(1) Pickup and Box Delete models include two-stage, variable rate springs. Chassis Cab models and Class A Motorhome Chassis
include single-stage, constant rate springs.



Using the above info I have come to the following conclusions:

The 4x2 and 4x4 X's have the same spring, and it's 2.5" thick w/6 leafs.
X's have a single rate spring of 410# per in., max of 2275# ea and 4550# pr.
250s and 350s have the same main spring. (2002), and it's 2.94" thick, overloads vary.
Fs have a 2 stage spring rate 320/670 # per in., max 2998# ea and 5996# pr.
If the As are 2" taller at rest and .44" thicker, unloaded that's 2.44".

Curb weight of an X rear is 3626#, and an F250 rear is 2391#. Thats like putting 1235# into the bed of the F250. Depending where the 2nd stage starts, that would drop the f250 1.93" in the back if the rate was still 320. Where does it start?

Based on curb weights, the sprung weight of the X is about 2826, and the F 1591. So the stock X pushes it's springs down 4.42", and would push the F's springs down 5.67" at the very worst. But the F's springs are thicker, so we take back .44" and I have lost .81" The arch is greater, so as long as the arch is different by more than .81" (more like 2") I should net 1.19".

In all fairnes, the secondary should start after the first 600#, so it would be more like 5.15" instead of 5.67", that puts me .29" below stock not including arch. 2" arch and it's up by 1.7".

From all I can find, The A's are the B's with different overloads on them, which I did not factor and I know I cant use.

 

WOW...that is some info. I wish I could understand it a little better. As far as the B codes being softer, I keep hearing of alot of folks saying the opposite. They are supposed to give a superior ride and not be so squirrely when towing like the stock X springs. The X's suffer from a gnarly case of axle wrap and the super-soft rear spring doesn't help. I actually tow 9500# with mine, so it's not a grocery getter.


What rig to the A codes come on?

Thanks,

SW

 

As i got are off a '02 PS 4x4 extended cab. That chart is in an excel file so it doesn't paste so well. But the fields do line up. The f250's are softer on the first stage and firmer on the second. The big differance is the bottom leaf. that's why the deflection is higher on the X but gross is higher on the 250/350.

 

I saw my post quoted on another site(tds). On that site since you are a member search that forum for posts by bruce1954. If he can't help you no one can.

Why did you strip my name when you copied my post?

 

relax dude...not trying to steal anything from anybody. I honestly didn't think it was that big of a deal. Is it? There is alot of confusion regarding differing height by swapping code springs.


As you know the search function sucks *** over there and I want to get as many actual users comments as possible to avoid making a mistake. Do a search and you'll see as many theory's as there are people on TDS.

Thanks for your input, and I"m sorry if I didn't quote you...I think??

SW

 

No, you're ok, sorry if that read a little harshly.

I'm serious about bruce 1954. He has done extensive research on this, and I'm sure if you found the height chart, he made it. He will also tell you that your results may vary by an inch. Either way, that's too much block IMO, and if it were me I would like you be trying to reduce or eliminate it. I have heard of guys rearching springs and loosing the block all together but have no first hand info.