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Wheel offset

Discussion in 'Lifted & Offroad Suspension' started by groceryman, Dec 25, 2010.

  1. groceryman

    groceryman Rockstar ROTM Winner 100 Posts

    Looking at some wheels some ION 133s 16x8 what offset do i need to be looking for i dont want them to stick way out past the fenders alot
  2. adampaul1964

    adampaul1964 Epic Member 5+ Years ROTM Winner 1000 Posts

    Here's a pic showing what mine look like with 20x8.5 with 31mm offset, I should think you should be fine with anything between 12mm to 31mm, remember the closer to 0mm the more they will stick out

  3. stephan

    stephan Rockstar 4 Years 5000 Posts

    Groceryman, don't fall into the trap of confusing offset with backspacing. Here's an explanation that should clear it up for you...

    Backspacing and Offset
    Before mounting a set of aftermarket wheels, there are some dynamics involved with fitment that are best to understand first.
    1. Wheel Diameter. This is the diameter of the wheel. Stock wheels are commonly 15 or 16 inch diameter. This dimension is usually in 1 increments (i.e. 15, 16, 17) but some manufacturers offer 16.5, which is rare.

    2. Wheel Width. This is the width of the wheel, measured inside the outer lip of the wheel. This dimension is usually in 1/2 increments (i.e. 7.5, 8)

    3. Wheel Center. This is the center of the wheel in relation to the width.

    4. Offset. The distance from the centerline of the wheel to the face of the mounting surface of the wheel that contacts the hub4.1 Zero Offset. Indicates the mounting surface is at the wheel center.

    4.A. Negative Offset. Indicates the mounting surface is behind (or inboard) the centerline of the rim. This is often found on standard rear-wheel-drive vehicles and on so-called reversed rims. (Diagram below shows negative offset)

    4.B Positive Offset. Indicates the mounting surface is in front of (or outboard) the centerline of the rim. This is often found on front-wheel-drive vehicles. Stock Tacoma wheels have Positive offset.

    5. Backspacing. The distance from the mounting surface to the inside lip of the wheel. This measurement is closely related to offset (without actually measuring, backspacing is about equal to [Wheel Width / 2] + [Offset] + [about 1/4] ).

    6. Centerbore. The centerbore of a wheel is the size of the machined hole on the back of the wheel that centers the wheel properly on the hub of the car. This hole is machined to exactly match the hub so the wheels are precisely positioned, minimizing the chance of a vibration. This measurement may be critical to clear the hubs of a 4WD.

    7. Bolt Circle. Also known as PCD (Pattern Circle Diameter). The bolt circle represents the diameter of an imaginary circle that goes through the center of the bolt holes. 4x2 Tacoma Bolt Circle: 5 lug on 4.5 PCD; 4x4/Prerunner Tacoma Bolt Circle: 6 lug on 5.5 PCD.​
    (Diagram: Alloy Wheel Cross-Section
  4. groceryman

    groceryman Rockstar ROTM Winner 100 Posts

    Ok thanks guys this helps

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