FJ40 or FJ55 Spring Packs for SOA: which is better?

Discussion in '40- & 55-Series Tech' started by truggier, Nov 20, 2005.

  1. truggier

    truggier

    Messages:
    289
    Likes Received:
    7
    Joined:
    Oct 18, 2005
    Location:
    Camp Verde, AZ
    I've been agonizing about this decision for while now and read up as much as I can. However, it's still not clear to me and I would appreciate some opinions.

    Any of you who recognize my handle may realize that a few short weeks ago I was hanging tough by my decision of staying SUA with a MAF shackle reversal and 2.5 OME spring lift. However, after hearing enough people tell me to go SOA while I've got the cruiser torn down this far ('cuz I'll just want to do it later anyway), I decided to ditch the previous idea and go SOA in the front with a shackle reversal and do a 4-link suspension in the rear, both compliments of Proffitt's.

    Now, regarding the front SOA...which is better, flipped stock FJ40 springs or stock FJ55 springs? The pros/cons in my mind for each are:

    FJ40 spring pros (flipped): Moves the axle forward approx. 3.5" for better approach angle and longer wheelbase. Also, since they're shorter, the rear shackle hanger doesn't need to be moved further down the frame, and the lift of the rig increased accordingly by approximately one inch over the 5.5 inches of lift that the SOA is already providing (the lower the better IMO). Lastly, if the springs are less 'flexy' than FJ55 springs, I'm guessing the rig won't lean quite as much on turns for on road manners.

    FJ40 spring cons (flipped): Less flex. Front shock towers, bump stops need to be moved?


    FJ55 spring pros: More flex. No need to move shock towers, bump stops.

    FJ55 spring cons: Keeps axle in stock location. Rear shackle hanger is moved and lift of rig is increased. Leans more on curves.



    So...which is better? I realize this is largely a matter of opinion and preference. Also, it I'm wrong about some of my assumptions above, please let me know.
     
  2. truggier

    truggier

    Messages:
    289
    Likes Received:
    7
    Joined:
    Oct 18, 2005
    Location:
    Camp Verde, AZ
    Forgot to say, this is on my '66 fj40.
     
  3. inkpot

    inkpot SILVER Star

    Messages:
    13,026
    Likes Received:
    2,508
    Joined:
    Jan 30, 2003
    Location:
    Chandler, Az.
    Howdy! Where are you located? I have a set of FJ-55 springs available in the Phoenix area. John
     
  4. truggier

    truggier

    Messages:
    289
    Likes Received:
    7
    Joined:
    Oct 18, 2005
    Location:
    Camp Verde, AZ
    Hey John. Go figure, I'm in Arizona too, Camp Verde to be specific. Are the FJ55 springs fronts or rears?
     
  5. inkpot

    inkpot SILVER Star

    Messages:
    13,026
    Likes Received:
    2,508
    Joined:
    Jan 30, 2003
    Location:
    Chandler, Az.
    Howdy! I have both sets. They are the original stockers from my 76 Piggy. They are in fairly good condition. I have a habbit of running with way too much weight onboard, so they did get flattened out some, but they still have some arch to them. I switched to the SOR heavy duty set, and those are holding up a little better. I think they would work just fine on an FJ-40. I had them sold to a guy in Texas last year, but the freight was just way too much for 1500 miles. PM me or reply to tlc76@cox.net of your interested. John
     
  6. Josie'sLandCruiser

    Josie'sLandCruiser Stop calling it a "FJ."

    Messages:
    5,173
    Media:
    10
    Albums:
    1
    Likes Received:
    182
    Joined:
    Feb 4, 2005
    Location:
    Seattle, USA
    Hi All:

    Are you speaking of stock 40 Series front spring versus stock 55 Series front springs? I believe they are about the same length; the FJ55 is known for a short front drive shaft.

    If you are speaking of mounting rear springs in the front, the 55 Series rear springs are longer than the 40 Series rear.

    Regards,

    Alan
    Seattle
     
  7. truggier

    truggier

    Messages:
    289
    Likes Received:
    7
    Joined:
    Oct 18, 2005
    Location:
    Camp Verde, AZ
    :doh:

    Sorry, I mean the rear FJ55 spring packs.
     
  8. snailwagon

    snailwagon

    Messages:
    1,042
    Likes Received:
    4
    Joined:
    Jun 11, 2004
    Location:
    high desert, ca
    I guess whichever is better is really your call, you summed up the pros and cons, now which one outweighs the other? So given your potential setup, having that front axle moved up a bit would be nice, especially since you have an SR. But then you might want to match the front and rear suspension a little better, which the 55 springs would do. Or you order a pair of custom length springs, around the length of rear 55 springpacks, with the springpin moved forwards a bit. Oh, decisions.
     
  9. truggier

    truggier

    Messages:
    289
    Likes Received:
    7
    Joined:
    Oct 18, 2005
    Location:
    Camp Verde, AZ
    Thanks to everyone for all of the input so far.

    I noticed that in Woody's articles and posts, he mentions several times that it was necessary to lift the front end about an inch to properly accomodate the rear 55 spring packs with the front SOA. Does anyone know if it's really necessary to do this? Couldn't the shackle hanger be located further up in the frame or shorter shackles be used?
     
  10. Planet_X

    Planet_X

    Messages:
    190
    Likes Received:
    0
    Joined:
    Feb 8, 2002

    Maybe we are talking about the extension of the front frame horns-1.5" ?

    Stock springs seem to do a good job infront, its the backend that does not like to move so much. Inboarding of the rear spring packs or widening the rear axle seems to be the obvious fix for the rear.
     
  11. truggier

    truggier

    Messages:
    289
    Likes Received:
    7
    Joined:
    Oct 18, 2005
    Location:
    Camp Verde, AZ

    I'm using the Proffitt's kit for the front SOA, which doesn't extend the frame horns. Therefore the rear shackle hanger needs to be located further down the frame and is lower since the frame curves down at this point. To keep the spring level, it then becomes necessary to lower the front fixed hanger about an inch. The net effect is raising the front end an inch over what the SOA provides, which I'm not keen on.

    Maybe lowering the front fixed hanger is not necessary...has anyone ever run on front springs where the front and rear spring eyes are not level - the rear spring eye is about an inch lower?

    Regarding the rear, I've decided to go with a 4 link for that. I'm pushing back the rear axle as far as it can go without cutting around curve of the fender...should give about a 103" wb.
     
  12. woody

    woody unhelpful spotter Staff Member Admin

    Messages:
    10,881
    Media:
    317
    Albums:
    8
    Likes Received:
    2,793
    Joined:
    Jan 15, 2002
    Location:
    Toquerville UT
    IMO, there is little reason to keep the spring level...the rear FJ55 packs installed on my front suspension are done similar to the Proffitts kit (and I'm redoing it this winter with their tab) and the rear is thru the frame. I've redone mine 4-5x since the online writeups, and it's definitely low.

    The KEY problem is your power steering...a Scout pitman will contact the spring pack on compression, but a mid-bump-stop just ahead of the pitman swing will limit that.

    Run GM Sag and it's a non-issue...however, my tie rod would contact the frame even when it was clearing the packs by 1/4"....it's TIGHT, but doable.
     
  13. Planet_X

    Planet_X

    Messages:
    190
    Likes Received:
    0
    Joined:
    Feb 8, 2002
    Myself I am shooting for keeping the spring hanger side (positive/non shackle side) lower than the shackle (negative side). Factory looks like they (toyota) get close to keeping the springs level.

    The SR's I have seen, seem to get the slope of the springs backwards, esp. with the flush spring hanger mount, even with bushing for the shackles up in the frame.

    I did order a set (just the front) of SOA specific Alcans w/ eyes reversed/stock measurements. When they show up I'll post anything specific.

    The steering is as Woody, states something to account for, myself I could use a longer pitman arm or move axle even farther forward, but this looks pretty odd when running stock fenders.


    The orientation of the front spring hanger vs. shackle end up or down is coming from a circle track tech leaflet. Do not really know how much of that information applys to our applications.
     
    Last edited: Nov 21, 2005
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.