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wheelbackspacing

Discussion in 'The Garage' started by TXsizeK5, Feb 5, 2003.

  1. TXsizeK5

    TXsizeK5 1/2 ton status

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    what is stock backspacing ?

    4 in the front 2.5 in the rear right? thats what ive herd. If i have 10bolt front and 14bolt rear will the back tires stick out further with teh same backspacing? Thanks,
    dC
     
  2. heavy4x4

    heavy4x4 1/2 ton status

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    No, 4" front and back...it's not different, otherwise you'd have to switch the front tires onto the rear rims when you rotate the tires.
    Now, if you went with the spacing you said....you'd have the same width out back as you do up front.
     
  3. TXsizeK5

    TXsizeK5 1/2 ton status

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    wouldnt you have less width with 2.5 back and 4 front?
     
  4. heavy4x4

    heavy4x4 1/2 ton status

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    Well, the rear axle is 3" narrower than the front, so let's do some math.
    Let's say we want to match the width up front exaclty when it's running rims with 4" backspacing. To do this, most people would run a 1.5" spacer on each side of the rear axle - then mount the 4" backspaced wheel/tire on the spacer. This would line up front and rear widths perfectly. Now, if you were to put rims on the front with 4" backspacing and 2.5" on the rear - that would move each rear wheel out 1.5", thus matching the fronts width.
    Make sense to you? I can never tell if my explanations are easy to follow. /forums/images/graemlins/smirk.gif
     
  5. TXsizeK5

    TXsizeK5 1/2 ton status

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    hmm i still dont udnerstand... maybe i dont know what backspacing does? /forums/images/graemlins/confused.gif /forums/images/graemlins/crazy.gif
     
  6. MEPR

    MEPR 1/2 ton status

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    my understanding of backspacing is how far the center of the wheel is in from the outside edge.
     
  7. GMtrucklover

    GMtrucklover Registered Member

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    naw thats offset. Backspacing is if you were going to set the wheel flat on the ground, top side up, and stick a tape measure from the ground to the backside of the wheel. Thats back spacing.
    If you were going to set the wheel on the ground facing down ward and stick the tape measure from the ground to the face of the wheel that is off set.
    Off set will change with different wheel withs, going from an eight" to an ten" the off set will vincrease 2". You have to becarefull when messing around with backspacing. Chevy chose the 4" very carefully when engineering the blazers if you go with to little it will go through bearings fast and handle like crap. If you go to much it may rub on tie-rod ends and also handle like crap. /forums/images/graemlins/thumb.gif
     
  8. ZonkRat

    ZonkRat 1/2 ton status

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    Backspacing is from the mounting surface to the inner edge of wheel{towards inside of truck}.Offset is where the mounting surface is in relation to the width of wheel.If wheel is 8in wide and mounting surf.is 4in from either edge it has 0 offset.8in wheel with mounting surf.2in from inner edge has 2in positive offset.8in wheel with mounting surf. 6in from inner edge has 2in neg. offset.Hope that helps. /forums/images/graemlins/crazy.gif /forums/images/graemlins/truck.gifer in TENN. /forums/images/graemlins/thumb.gif
     
  9. ChevyCaGal

    ChevyCaGal 3/4 ton status

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    I thought I understood it but now I am confused...

    Anyone have a unmounted tire they can take a didgi pic of it and then draws lines on it with MS Paint or something that would make it clear with an actual visual?
     
  10. balzackks84

    balzackks84 1/2 ton status GMOTM Winner

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    /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif

    This is backspacing

    [​IMG]

    Offset is if the mounting surface is in the midle of the rim then measure how far away from center that is. IE: If you had a 10" wheel with 3" BS your offset would be 2"
     
  11. Topdown

    Topdown 1/2 ton status

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    I have an unmounted wheel and can take a pic of it, but after reading this post, I am confused too. I think the deal is this... someone correct me if I am wrong.

    to make it simple lets say wheel center = where the wheel bolts on. So...

    from BACK of wheel to wheel center is backspacing.
    from FRONT of wheel to wheel center is offset.

    yes?

    -Ryan /forums/images/graemlins/k5.gif
     
  12. balzackks84

    balzackks84 1/2 ton status GMOTM Winner

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    Wheel offset is measured from mounting surface to center of rim. Thus the title "offset" from center. Lemme try this again. If a 10" wheel has NO offset that means it has 5" backspacing. If a 10" wide rim has 2" offset it has 3" bakcspacing (now im not too sure on which way that would go and if negative or positive would denote whether it went in or out /forums/images/graemlins/tongue.gif) But thats the jist.

    If im wrong so be it but im pretty sure on this one.

    And to keep with the original post the stock GM rims had the same backspacing. Probably 4" but im not sure. People have different BS in order to compinsate for the shorter width of GM rear ends. But like said before if you wanted to rotate tires with different BS you have to actually dismount and remount the tires on your rims.
     
  13. Topdown

    Topdown 1/2 ton status

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    gotcha... now it makes sense. Thanks!!

    -Ryan /forums/images/graemlins/k5.gif
     
  14. Shaggy

    Shaggy 3/4 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    from BACK of wheel to wheel center is backspacing.
    from FRONT of wheel to wheel center is offset.

    [/ QUOTE ]

    <font color="green"> Close, you got the backspace part right, it's measured to the surface that meets the hub, the part that touches the part of the truck that the wheel bolts to. The inside face of the wheel center. I'll refer to that as WMS for wheel mounting surface.

    Offset seems to be the one throwing people for a loop here. OK, let's say that we have a 10" wheel. If it had 5" of backspace it would have zero offset. Zero offset means that the WMS is the same distance from both the inner and outer edges of the wheel.

    If the 10" wide wheel had 4 inches of backspace it would have 1" offset, since the WMS is 1" closer to the inside edge of the wheel. You with me? The center of the wheel is 5" from the inside edge, 5"(half the width of the rim) minus 4" (the backspace) equals 1" of offset.

    OK, so that's positive offset. Negative offset would be if the distance from the WMS to the inner edge of the rim is farther than the distance from the WMS to the outside edge. So a 10" wide wheel with 6" of backspace would have 1" of negative offset. 5"(half the width of the rim) minus 6" (the backspace) equals -1" of offset. Get it? /forums/images/graemlins/thumb.gif

    *EDIT*
    Damn, must be typing slow tonight... /forums/images/graemlins/crazy.gif
    </font color>
     
  15. ZonkRat

    ZonkRat 1/2 ton status

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    Heres a couple pics that might help.They are from Oct.97 Petersons.don't know how to put in post.Look in Member Galery in ZonkRats pics.
     
  16. ZonkRat

    ZonkRat 1/2 ton status

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    Not to change subject,but,how do you move pics from members to posts.Just put 2 there for this and would like to know. /forums/images/graemlins/thumb.gif
     
  17. balzackks84

    balzackks84 1/2 ton status GMOTM Winner

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    [​IMG]

    [​IMG]

    Go to your pics, right click on the pic, go down to properties, highlite the address of it, right click again, select copy, come back to reply page click on the <font color="blue">Image</font color> tage and paste address. /forums/images/graemlins/thumb.gif
     
  18. ZonkRat

    ZonkRat 1/2 ton status

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    Thanks.I'm new to all this.I'll learn it eventually /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  19. balzackks84

    balzackks84 1/2 ton status GMOTM Winner

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    When stuff doesn't work just pee on it. Works every time. /forums/images/graemlins/thumb.gif
     
  20. ZonkRat

    ZonkRat 1/2 ton status

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    It's wifes puter.She might not like that. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
     

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