Wheelfitment

How to Measure Bolt Patterns

How to Measure Wheel
BackSpace

Items required to measure wheel backspace:
Tape measure
Straight edge
Wheel w/o tire (preferred)

The easiest way to measure backspace is to lay the wheel face down onto the
ground so the backside of the wheel is facing up. Take a straight edge and lay
it diagonally across the inboard flange of the wheel. Take a tape measure and
measure the distance from where the straight edge contacts the inboard
flange to the hub mounting pad of the wheel. This measurement is
backspace. The above photo shows three wheels with 2",3", & 4" backspace.

Measuring Wheel Offset

To calculate offset you'll need the following measurements:

Wheel backspace
Wheel Center line (outboard flange to inboard flange measurement / 2)

Subtract:
Wheel center line from Wheel backspace to get offset.
If backspace is less than the wheel centerline the offset is negative.
If backspace is greater than the wheel centerline the offset is positive

Tip:
To convert from inches to mm multiply by 25.4
To convert from mm to inches divide by 25.4

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
The hole at the center of the wheel.

Rear spacing or back spacing
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.

Bead-Loc
A device which captures the tire bead between it's flanges, usually secured by bolts to
keep tire bead from dismounting. Usually used in dirt circle track or off road
applications where low tire pressures are used and hitting ruts or other vehicles are
common. Left: An example of a Bead-Loc wheel

Lug Size Ft                  Lbs Torque
7/16"                                    55-65
1/2"                                      75-85
9/16"                                   95-115
5/8"                                   135-145
14mm                                  85-95

IMPORTANT NOTICE:
As with all types of wheels retorque lug nuts after the first 25
miles & at 100 mile intervals until lug torque is maintained.
Note: Always refer to Owner's Manual for proper factory
specifications that take precedence over the listed
recommendations.