Determine the bolt pattern on the trailer wheel by the number of bolts and the bolt circle. To determine the bolt circle on wheels with an even number of bolt holes, measure center-to-center on bolt holes directly across from each other on the diameter (Example: 8 on 6-1/2 would mean 8 bolt holes with 6-1/2" center-to-center diameter). On odd number bolt wheels, measure any bolt hole center to the point halfway between bolt holes on the diameter (Example: 5 on 4-1/2 would mean 5 bolt holes with 4-1/2" measured to a point halfway between the opposite bolts).

• If D = 2-5/8" then the bolt pattern is a 5 on 4-1/2
• If D = 2-3/4" then the bolt pattern is a 5 on 4-3/4
• If D = 3" then the bolt pattern is a 5 on 5
• If D = 3-1/4" then the bolt pattern is a 5 on 5-1/2

Offset is the distance between the mounting face of the disc and rim centerline.
Inset: Refers to the distance when the mounting face is outboard of the rim centerline.
Outset: Refers to the distance when the mounting face is inboard of the rim centerline.