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3.5 or 4.0s in the Rear

Discussion in 'Ford Raptor Problems and Questions Forum' started by Clockton, Dec 2, 2018.

  1. Clockton

    Clockton Full Access Member

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    I am upgrading the OEM suspension and going through the bed. I have some that say 3.5s are the way to go and others that say go 4.0. Probably doing 5k+ miles a year Offroad and 10-15k on pavement

    Pros and Cons for each?
     
  2. zombiekiller

    zombiekiller EXO Crewmember

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    go 4.0s. for the price difference between the two, you get a TON more beef (shaft diameter, etc.), larger fluid volume, less potential to break and more adjustability.

    I love mine. plus the 3.5s don't say King Kong on them like the 4.0s.
     
  3. Clockton

    Clockton Full Access Member

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    I don't think these trucks have enough weight to really move the 4.0 beef and so they will be tough to get into the sweet spot. Some 6100's are running 3.5s which is the direction I am leaning
     
  4. zombiekiller

    zombiekiller EXO Crewmember

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    the 6100 that I had my hands on last week is running 4.5s.

    Yes, it is a lot of fluid but my truck with the 4.0s is full "dirt Cadillac" with the long compression out 3 turns , the medium length in 1 turn and the short, prep-bump in 4 turns.

    I set my king bumps to 90 psi ( they come at 200) and I'm now pretty dialed with 2 spares, all my tools and all my recovery gear in the truck, plus a cooler with a case of beer and 3 bags of ice.

    3.5 or 4.0 as far as " moving beef" is immaterial. Its all about what pressures you're running and getting the compression and rebound dialed.

    more fluid = cooler fluid = less shear = longer time between rebuilds + the ability to hit whatever you want.

    I also went 18" stroke in the event i decide to go sprung under at a later date.

    That being said, once i put extended shackles on the truck, it sits level with a full loadout ( non-HD deaver +3s), I gained almost 4 inches of droop and my SDHQ stainless brakelines are terrifyingly too short. I'm going to get a set of rears made that are 5" longer than the sdhq lines. Once theyre in, I'll measure from full bump to full droop, but I think it'll be in the 24" of wheel travel realm.
     
  5. Clockton

    Clockton Full Access Member

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    I think I am going with SVC and Shaffers Offroad advice on this one. 3.5s with valving that SVC has figured out. Thanks for the detailed input


    IMG_7435.jpg
     
    Last edited: Dec 3, 2018
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  6. zombiekiller

    zombiekiller EXO Crewmember

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    all good. my entire suspension is SVC. wait until you see the difference between 3.5s and 4.0s in person. it is kind of crazy. For reference, i have 3.5s on the front of my truck and 4.0s on the rear. ( 2.5" coilovers in the front supporting the truck).

    Regardless, you're going to love the difference in the truck going to a bypass rack. the svc dudes are a rockstar crew.
     
  7. RDFTS

    RDFTS aka Rick Supporting Member

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    That right there is a reason to go bigger, nobody likes when all your beer is popped.
     
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  8. Don N

    Don N Full Access Member

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    Old post, but one of the possible options I am deciding between right now is 3.5 vs 4.0 in the rear. What did you end up going with and how did it work out for you?
     
  9. Bowewelding

    Bowewelding Full Access Member

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    With my +3 sd deaver and +2" rpg shackle it sits level and with the 16 x 3.5" shock its supposed to pull 18" of wheel travel. It would of all been on by now but i had to lemon law the 17 i had, and now shopping for a 2020. Also have +6" rpg brake lines. Gonna do the live valve delete and install all these goodies that are just pialed up in the garage for now. Can't wait, I'll count travel numbers when I install it all. 24" of wheel travel sounds like alot even with 18" stroke shocks but i don't know for sure
     
  10. Bowewelding

    Bowewelding Full Access Member

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    Very clean set up..how long are those shocks and how much travel are you getting at the wheel??? Im kicking around the idea of the bolt kit from rpg and running my oem 3.0 king but there's contradicting travel numbers out there on the interweb
     

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