Custom Wheel Technical Information

How to Measure Your Bolt Pattern

How to Measure The Back Space on a Wheel

The easiest way to measure the backspace of a wheel is to lay the wheel face down on a smooth surface so the backside of the wheel is facing upward. Take a straight edge and lay it diagonally across the inboard flange of the wheel. Use a tape measure to measure the distance from somewhere on the straight edge directly downward to the hub mounting pad of the wheel. Your measurement will be the backspace in inches. See photo showing three wheels with 2″,3″, and 4″ backspace measurements.

custom wheel technical information
Wheel Backspacing Examples

Determining Your Vehicle Fitment

Fitting a wheel and tire package is different for each vehicle, but by following these guidelines your chances for success will be much greater.  In most cases you can use the physical dimensions of the current wheel and tire assembly to determine the dimensions of the new wheel and tire package.

Determining Wheel Caliper Clearance

  • A – Caliper Overhang Distance: Used to determine if wheel dish is adequate (in some cases, a spacer may be required for clearance
  • B – Diameter of Hub Center: Required if wheels are hub centric
  • C – Wheel Stud Diameter: Required along with bolt circle
  • D – Height of Hub Center
  • E – Length of Lug and Thread Type (Fine or Coarse): Required to determine if longer studs are necessary
  • F – Distance from CL of Hub to Caliper: Used with A to determine if a spacer is required for proper fitment
  • G – Width of Caliper: Used with F to determine if wheel ID is adequate to clear rotor/caliper package
  • H – Diameter of Hub Mounting Face: Used to determine if hub is adequate to support wheel/spacer

Caliper Hub Diagram
Caliper Hub Diagram

Lug Torque Specs (generic)

It is always best refer to your Owner’s Manual for proper factory specifications that take precedence over any listed recommendations.

Wheel Terminology

  • Bolt pattern or lug pattern or bolt circle is determined by the number of bolt holes and the bolt circle diameter.
  • Hub Diameter or center bore is the hole at the center of the wheel.
  • Rear spacing or back spacing is the distance from the backside of the wheel mounting pad to the outside of the rim flange.
  • Offset:  The distance from the centerline of the wheel to the mounting surface of the wheel.
  • Negative offset:  When the back of the bolt pad is closer to the inside of the wheel; when mounting surface is inboard of the rim centerline.
  • Positive offset:  When the back of the bolt pad is closer to the street side of the wheel; when the mounting surface is outboard of the rim centerline.

TIRE TECHNICAL INFORMATION