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Thread: Offset Reference Ranges - "Will it Fit?"

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    Now it's a Party SpeedRacerX's Avatar
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    Default Offset Reference Ranges - "Will it Fit?"

    I scoured both Boards and analyzed dozens of threads and hundreds of posts to compile a list of wheel offsets based on rim width that seem to be working for people. Looking for larger and/or wider wheels & tires myself, I know how challenging this can be.

    I was able to find 30-40 posts that mention complete wheel & tire measurements and had photos. I did not include anything where the pictures looked like the tires sat at or outside of the fenders. I eliminated almost every mention of fitments that rub, except where I note it.

    Now, when I look for wheels, depending on the rim width I'm looking at, I can see if the offset I'm looking at falls into a generally accepted range that has been proven by other members.

    Hopefully others will find this useful. All offsets are +

    Front Wheels

    8" 35-48 Stock is +48 (18" & 19")
    8.5" 30-45 Majority are running 35-40.
    9" 38-51 Majority are running 38.
    9.5" 34-40

    Front Tires

    Stock is 245/45-18 or 245/40-19 Front and Rear.
    245 & 255 are most common. Even 265. Now 275. Some have tried 285.
    45-18 and 40-19 are common.
    245/40-19
    255/35-19
    265/35-19
    245/35-20
    255/35-20
    275/35-19 on 19x9.5 w/+40 offset or +45 w/5mm spacer

    Rear Wheels

    8" 48 Stock is +48 (18" & 19")
    8.5" 42
    9.5" 35-57 Majority are 42-45
    10" 40-55 Majority are 45, also 20x10 +60 with a 295/30-20 tucked and did not rub!
    10.5" 46-47 50 seen now too.
    11" 54

    Rear Tires

    275 & 285 are most common; up to 305 on lowered vehicle which required cutting & rolling.
    40-18 and 35-19 are common.
    275/35-19
    285/35-19
    305/30-19 (cutting & rolling)
    285/30-20
    245/35-20
    295/30-20 (tested only on 20x10 +60 so far - no cutting or rolling and it tucked)

    If anyone has any additional known fitments that do not cause rubbing issues OR if anyone sees any mistakes in here, please let me know and I'll add/change/delete to this list.

    Warning: I can't guarantee these fitments - they are only as good as the person who posted the result and my interpretation of the pictures...

    Approx. Measurements which might be helpful when looking at larger rear wheels & tires:

    - Inner Wheel Well Wall to Wheel Mounting Surface = 8.715"
    - Shock Bump-Out to Wheel Mounting Surface = 8.215"
    - Inner Wheel Well Wall to OS Edge Fender = 12.75" = 324mm
    - Shock Bump-Out to OS Edge Fender = 12.244" = 311mm
    - Inner Wheel Well Wall to OS Edge Fender Minus a .125" Rolled-up Flat Lip = 12.625"
    - Shock Bump-Out to Rolled-up Flat Lip = 12.125"
    - Shock Bump-Out Plus extra .125" Clearance to Rolled-up Flat Lip = 12.000"
    - Inner Wheel Well Wall to IS Edge of Non-Rolled Lip = 11.875"
    - Shock Bump-Out to IS Edge of Non-Rolled Lip = 11.375"
    - Shock Bump-Out Plus extra .125" Clearance to IS Edge of Non-Rolled Lip = 11.25"
    Last edited by SpeedRacerX; 02-07-2011 at 07:03 AM. Reason: Added Approx Wheel Well Measurements & Front 275
    R.I.P. Charlie

    "Any man's finest hour, the greatest fulfillment of all that he holds dear, is that moment when he has worked his heart out in a good cause and lies exhausted on the field of battle - victorious." - Vince Lombardi

    2009 G8 GT, MSM/Onyx, Prem, Mods: few......Dozen

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    VIP Member KEV-O's Avatar
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    i'm running on 245/35/20 all the way around
    wheels are 8.5" all the way around also
    i believe my offsets are 42

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    VIP Member Kermit's Avatar
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    GRRRR8 info Speed. Thanks for the leg work. This will sure help me once I start looking at getting different wheels.
    SOLD 2009 G8 GT MGM.
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    Now it's a Party SpeedRacerX's Avatar
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    Quote Originally Posted by KEV-O View Post
    i'm running on 245/35/20 all the way around
    wheels are 8.5" all the way around also
    i believe my offsets are 42
    Excellent. My first validation. Fits the width/offset range & known tire fitments above
    R.I.P. Charlie

    "Any man's finest hour, the greatest fulfillment of all that he holds dear, is that moment when he has worked his heart out in a good cause and lies exhausted on the field of battle - victorious." - Vince Lombardi

    2009 G8 GT, MSM/Onyx, Prem, Mods: few......Dozen

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    Now it's a Party SpeedRacerX's Avatar
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    Quote Originally Posted by KEV-O View Post
    Added your 8.5" +42 to the rear. Thanks!
    R.I.P. Charlie

    "Any man's finest hour, the greatest fulfillment of all that he holds dear, is that moment when he has worked his heart out in a good cause and lies exhausted on the field of battle - victorious." - Vince Lombardi

    2009 G8 GT, MSM/Onyx, Prem, Mods: few......Dozen

  8. #7
    VIP Member KEV-O's Avatar
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    don't forget the rear tires
    245/35/20

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    Senior Member jdeserio's Avatar
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    thanks for the list...
    Joel's 2008 liquid red g8 gt 888
    show mods: debadged except pontiac logo, 15% tint. gxp diffuser,5,000k hids and fogs. eibachs
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    441rwhp/412rwtq

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    Beyond Help SRG963's Avatar
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    Excellent Thread!

    Stock GT Wheels:
    19"x8" +48mm Offset



    Also, please load up the car with passengers to test rubbing issues.
    Last edited by SRG963; 11-19-2009 at 07:52 AM.
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  11. #10
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    I'm running:

    20x8.5 +40 with 255/35 - 20 Front

    20x9.5 +40 with 275/35 - 20 Rear

    Based on my results, your values are right on.

    Thanks for the excellent post, this will save people a lot of time.

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