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Up for new tires contemplating 39s

Discussion in 'Ford Raptor Wheels & Tires Forum [GEN 1]' started by PorterW1111, Apr 26, 2020.

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  1. PorterW1111

    PorterW1111 Full Access Member

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    Bought the truck awhile back and immediately put 37 grabber x3s, did the standard mid perch, cut pinch welds and correct wheel offsets. Have had it with no issues that way since then. But there has been alot of new since then so now that I’m up for new tires I’m think why not go 39”s...

    New to the truck since 37s: icon stage 4 suspension, frame cut front and rear bumpers, advanced fiberglass +2/2 fenders, 4.88 gearing, kHc slot delete, 17” icon rebound series wheels and a brand new PS pump w/larger reservoir.

    I’m not worried about having to cut and fabricate the firewall, though curious how much it needs to move. Wondering opinions and thoughts of 39s on a gen1 screw, looks, power loss, worth the extra work?, anyone that has a hookup on a set of 39s. 17” rim....
     
  2. 500mag

    500mag Full Access Member

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    I say go for it. 39" KM3s would look awesome....
     
  3. PorterW1111

    PorterW1111 Full Access Member

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    Did we just become best friends?!....lol
     
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  4. PorterW1111

    PorterW1111 Full Access Member

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    I’m curious though about the 13.5” width. I like how tall the 12.5 37”s look wondering if the 39”s will look fat?
     
  5. 500mag

    500mag Full Access Member

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    Not at 39" tall. There is one on here with those tires.
     
  6. PorterW1111

    PorterW1111 Full Access Member

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    Done! 39s ordered. And a pack of sawzall blades haha
     
  7. 500mag

    500mag Full Access Member

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    Looking forward to the pics.
     
  8. zombiekiller

    zombiekiller EXO Crewmember

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    you're gonna want a secondary bypass with those 39s.

    and, more than likely, you're going to need to not just cut the firewall, but also plate it.

    Ive seen one gen1 running the km3 39s. It was a mid-travel truck. he had a gen2 conversion one piece.
     
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  9. PorterW1111

    PorterW1111 Full Access Member

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    Curious what would make 39s need a secondary more than any other tire size? The suspended weight (the truck) is the same. Up force could be a little more as there could be more Upward momentum since they are heavier ? But not sure a 37” at ~75lbs and a 39” at ~85lbs would be that different

    for the firewall yes I fully plan to cut move and weld back in place.
     
  10. zombiekiller

    zombiekiller EXO Crewmember

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    you're going to be able to go faster, hit bigger holes and hit them harder. Combine all of this together and you're going to need more fluid volume and valving. The dynamics of the larger tires are also going to beg for the extra control that the secondary bypass offers.

    It isn't just about the tire weight. If anything, tire weight would kinda come in last place for the "why".

    The only rigs on 39s that I've seen NOT run a secondary bypass are substantially lighter trucks or rock crawlers.
     
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