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39.5 on a fj40?

Discussion in '40- & 55-Series Tech' started by godzilla, Apr 28, 2003.

  1. godzilla

    godzilla

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    What size wheel do I have to run with 39.5 boggers , what backspacing do I order, and will they hit the leaf springs. Has anybody done this before? I have a 71' fj40 with a soa lift and mini truck front hubs. Thanks
     
  2. woody

    woody Internet Fireman Staff Member

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    3.5" backspacing is your minimum, but with that size tire I'd consider pushing it to 2 or 2.5" I run 2" BS on my Allieds with 14.5 wide SX's and like it.

    What width are the 39.5's? Most commonly, 10" rims are used for anthing up to 15.5/16.5 wide, but you could go to a 12" rim if you really wanted the added width.n My 14.5's are on 10" rims, ideally I'd have found a set of 9" rims.

    Section width x .66 = suggested offroaders rim width.

    15.5 x .66 = 10.23 ~ 10"
    14.5 x .66 = 9.57" ~ 10"
    12.5 x .66 = 8.25" ~ 8"
    10.5 x .66 = 6.93" ~ 7"
     
  3. CruisinGA

    CruisinGA

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    Sorry to ask such a stupid question, but what exactly is backspacing, I know it has something to do with edge of wheel distance from centersection or the part of the wheel that bolts to the axle. I also know that 3.5" is ideal for most cruisers, but if that was "minimum" then wouldn't the number get larger instead of smaller? Just a quick little explanation would be nice, really appreciate it guys, this has baffled me and theres no one else I can ask. (None of my friends/family are much into wheeling) :-/
     
  4. woody

    woody Internet Fireman Staff Member

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  5. SpaceGhost

    SpaceGhost

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    I ran 38"s on my cruiser with leafs. 8" rims, 3.5" bs and yes they hit the springs. 2" of bs or maybe 10" rims and 3"s would have cleared. You can adjust the steering stops to avoid contact, but what fun is that? Oh and goodbye birfs.
     
  6. MD11Fr8Dog

    MD11Fr8Dog CM09 Eight Ball winner

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    No such thing as a stupid Q!! Here ya go!!

    [​IMG]
     
  7. CruisinGA

    CruisinGA

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    GREAT! :bow: JUST what I needed. That should go in the general Cruiser information page. So less backspacing equals wider footprint?
     
  8. MD11Fr8Dog

    MD11Fr8Dog CM09 Eight Ball winner

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    Not exaclty footprint, as in tire footprint, but width of your stance increases and less rubbing issues on the insides of the tires
     
  9. cruiserhk91

    cruiserhk91

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    backspacing won't be the issue here. using a stock width 40 axle you won't be able to turn full lock right or left with larger than 37" tires. the tires will hit the leaf spings. add about 6 to 8 inches to the width and you can run normal backspacing.
    running extreme offsets in the rim will increase the "scrub"
    while turning putting excessive loads on your steering components, perhaps to the point steering becomes impossible in very rough terrain