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Anyone running 39 km3 on their tundras?

Discussion in 'Wheels & Tires' started by channlan, Jan 27, 2021.

  1. Jan 27, 2021 at 10:13 AM
    #1
    channlan

    channlan [OP] New Member

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    Just curious if anyone has run 39 km3s on their tundras? I'm running 37s without any issues but I think our trucks would look awesome with a little bigger tires.
     
  2. Feb 12, 2021 at 11:28 AM
    #2
    Fillup21

    Fillup21 New Member

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    Have you had any running with the 37’s?
     
  3. Feb 12, 2021 at 11:30 AM
    #3
    GreatBallsOfFire

    GreatBallsOfFire "I wanna go fast" - Ricky Bobby

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    I think there are a couple of dudes running 40s but I’m not sure what sorta lift that would take. I can just barely fit 37s... 39s would be awesome but without some major mods I won’t be even close to clearing the body mount.
     
  4. Feb 12, 2021 at 3:38 PM
    #4
    channlan

    channlan [OP] New Member

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    I have some rubbing at full stuff but nothing serious. Been running it for about 6 months.
     
  5. Mar 10, 2021 at 2:04 PM
    #5
    BlackSheep

    BlackSheep caffeinated member

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    I've been on 37s for a couple years now...really wanting to try out 39s. I'd need gears for sure, cuz I'm still on stock 4.30s, and a high clearance front bumper, but I think I'd clear the UCA and the cab mount. I agree, OP, 39s on these trucks would look awesome.
     
  6. Mar 10, 2021 at 2:16 PM
    #6
    Getmeacoors

    Getmeacoors From the far Norcal

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    38 13.5 20 toyo mt. But I have about 8 inch lift. No rubbing unless fully stuffed and full turn on body mount but minimal. Wouldn't rub if I did the bmc better but it was my first attempt
    20190830_163144.jpg
     
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  7. Apr 16, 2021 at 1:51 PM
    #7
    Cruzer

    Cruzer Wheeling Full Size

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    Was thinking 40s but then read all of the mods needed and the potential steering rack issues so I just started looking at 39s (39x13.50r17 on 0 offset). Did a quick google search and it looks like KM3 are the only 39s out there.
     
  8. Apr 17, 2021 at 1:05 PM
    #8
    Half Assed

    Half Assed me ne frego

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    Kanati makes a 39x12.50r17
     
  9. May 5, 2021 at 6:08 PM
    #9
    Cruzer

    Cruzer Wheeling Full Size

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    I pulled the trigger. KM3 39x13.5r17
    I trimmed the rear section of the front fenders, and the front of the rear fenders. No rub in full lock.

    40A5EB99-99FE-4733-8F79-DFA5726AD144.jpg

    688F1BF8-D3BD-433A-879F-6A83B21B3CA0.jpg
     
  10. May 5, 2021 at 6:30 PM
    #10
    BlackSheep

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    :eek: That’s the sexiest thing I’ve ever seen, even if it’s white :boink:
     
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  11. May 5, 2021 at 6:48 PM
    #11
    BlackSheep

    BlackSheep caffeinated member

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    Think I could fit those with 3" front lift? :monocle:
     
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  12. May 5, 2021 at 6:51 PM
    #12
    kidrman

    kidrman New Member

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    I don’t see why you couldn’t, just a little trimming. Jk
     
  13. May 5, 2021 at 7:52 PM
    #13
    channlan

    channlan [OP] New Member

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    That looks so good. You running any spacers?
     
  14. May 5, 2021 at 8:55 PM
    #14
    Cruzer

    Cruzer Wheeling Full Size

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    Thanks! No spacers. The 13.5” wide tires on 8.5” wide wheels stick out nicely.
     
  15. May 7, 2021 at 5:54 PM
    #15
    BlackSheep

    BlackSheep caffeinated member

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    God, I keep staring at this pic. I gotta do this. I need to put more miles on my truck, at the rate I’m going, I’ll have my current tires another four years :rofl:
     
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  16. May 7, 2021 at 6:21 PM
    #16
    Cruzer

    Cruzer Wheeling Full Size

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    At least I'm not the only one staring at it :rofl:
     
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  17. May 8, 2021 at 5:33 AM
    #17
    BlackSheep

    BlackSheep caffeinated member

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    @Cruzer a few questions...
    How hard were those 39s to balance?
    Is the ride alright?
    How’s the contact patch with 13.50” tires on 8.5” wheels?
    What psi do you have them set at?
    How’s the throttle response feel with 5.29s?
     
    300BLK likes this.
  18. May 8, 2021 at 6:32 AM
    #18
    Cruzer

    Cruzer Wheeling Full Size

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    The shop didn’t seem to have any issues balancing them. They feel great on the road, I’ve gone up to 90mph with no issues. The max psi on the tire is 45lbs so I drive around with them at 35lbs. The ride is smooth, I don’t really feel any bumps with so much tire. It’s very quiet for MTs, the most quiet MTs I’ve had so far. Definitely can’t take corners like I did with 37s.

    I usually air down to 12lbs and my previous tires (STT Pros, X-MTs) they will noticeably flatten out (on 37s) especially the front wheels. I aired down to 12lbs on these KM3s and it was hardly noticeable BUT when I hit the obstacles they we’re definitely soft, pliable, and wrapping itself around the rock/tree log. My belief is that with narrow wheels and wide tires that it is harder to pop a bead because the tire, in its pre-mounted state, is about the same width as the wheel at the rim so it’s not trying to retract itself like it is on a 10 or 12” wide wheel - just my theory.

    I think throttle response is great. When I step on the pedal from a dead stop it just goes.
     
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  19. May 8, 2021 at 6:58 AM
    #19
    BlackSheep

    BlackSheep caffeinated member

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    Thanks for the response :thumbsup:

    My RWs are 8” wide I believe...wonder how that would work out
     
  20. May 8, 2021 at 6:59 AM
    #20
    Cruzer

    Cruzer Wheeling Full Size

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    Most 13.5 wide tires recommend the minimum width to be 8.5" wide. Might not be safe on 8"?
     
  21. May 8, 2021 at 7:05 AM
    #21
    BlackSheep

    BlackSheep caffeinated member

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    Yeah that’s what I was thinking...my 12.50s on 8” wheels are about as wide as I can go I think.
     
  22. May 20, 2021 at 6:00 PM
    #22
    channlan

    channlan [OP] New Member

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    @Cruzer if you were to go 40s were would it rub? I'm thinking of skipping 39s and going straight to 40s.
     
  23. May 21, 2021 at 7:04 AM
    #23
    Cruzer

    Cruzer Wheeling Full Size

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    Yes, I think it would rub.

    These KM3s are not as square as most MTs, they are actually coned in where the tread meets the sidewall. Here were my 37" MTs, you can see its pretty square at the corner.

    IMG_6519.jpg

    Here are the KM3s
    cornertire.jpg

    Here it's more noticeable. If it wasn't coned in it would be close to the top of the rear fender.
    cornertire2.jpg

    Also, with bigger tires come bigger problems. I took it out on the trails on its maiden voyage and damaged my front diff :mad: Wasn't expecting that, thought I would break a CV axle first, which I would have preferred.

    To beef up the front end I ordered RCV axles ($2k), I'm having large chromoly inner tie rods made, already have the CB outer tie rods. But we can't do sh!t about beefing up the front diff internals.
     
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  24. May 21, 2021 at 7:09 AM
    #24
    BlackSheep

    BlackSheep caffeinated member

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    Yikes...not an inspiring start to your ride on 39s. Gives me a little pause about going that route myself...
     
  25. May 21, 2021 at 7:27 AM
    #25
    channlan

    channlan [OP] New Member

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    What kind of damage was done to the diff? I thought that the 5.29 gears would be enough to compensate for the heavier tires.
     
  26. May 21, 2021 at 7:30 AM
    #26
    Cruzer

    Cruzer Wheeling Full Size

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    I'm taking it to the shop on Monday but I'm thinking a spider gear is shot.
     
  27. Jun 13, 2021 at 4:42 PM
    #27
    Cruzer

    Cruzer Wheeling Full Size

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    Thought I'd give this thread an update.

    Turns out I snapped a stub shaft and the crazy thing is that Toyota does not sell this stub shaft. You would have to buy a whole front differential assembly, which would include the stub shaft. I was lucky that I had a spare differential laying around.
    IMG_6749 (1).jpg

    Since fixing this issue 3 weeks ago I have broken 3 CV axles and a steering rack. Thinking about going big? Might want to think again.
     
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  28. Jun 13, 2021 at 6:10 PM
    #28
    BlackSheep

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    Damn that’s crazy. Are you going to drop back to 37s?
     
  29. Jun 13, 2021 at 6:20 PM
    #29
    Half Assed

    Half Assed me ne frego

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    Damn. That's why I ordered 37s for mine.

    Bigger isnt always better, I learned that the hard way too.

    And 13.50s on a 8" wheel i would run that. Ive run 12.50 on a 6" wheel no problem. There will be a crown to the tread though, i just lowered tire pressure.
     
  30. Jun 13, 2021 at 6:30 PM
    #30
    YotaMan

    YotaMan Silver Bullet

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    All this convo, maybe I'm in the wrong place or just fucking stupid

    But what lift are ya'll running with these 39's? Haven't seen that mentioned
     

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