Bolt Pattern

Bolt Pattern  (Bolt circle diameter "b/c")

bolt pattern

The diameter of an imaginary circle drawn through the center of each lug. This is how wheels are usually described in lieu of specific car applications (i.e. 5 on 4.5 In this case, 5 denotes the number of lugs).

Mounting Pad, or Face of Hub 

The back of the wheel center that makes contact with the brake drum, or hub flange on an axle.

trailer wheel

 

The distance between mounting surface (bolt pad) of the wheel and the center line of the wheel. (All wheels have offset, even if it is zero.)


Negative Offset


When the back of the mounting surtace (bolt pad) is closer to the disddrum side of the wheel.  Negative offset increases the "track" of the vehicle, because the center line is moved away from the vehicle towards the street. This is what is referred to as the "deep dish" look.


Positive Offset

When the back of the mounting surface (bolt pad) is closer to the street side of the wheel. Positive offset reduces the "track" of the vehicle, because the center line is moved away from the street towards the vehicle.