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Basic Rim Facts

rims-slow-speed-thSlow Speed Rim

Slow Speed Rims

Slow Speed Tire/Wheel Assemblies and Rims represent the largest proportion of the small wheel business. Slow Speed Wheels are found on everything from children's wagons, to wheel barrows, hand trucks, outdoor power equipment, casters and industrial trailers.

When ordering slow speed wheels, you need to know a few items:

  • Tire Size
  • Hub Length - what is the overall length of the wheel hub from outside to outside of bearing
  • Hub Offset - is the hub centered or offset? If offset what is the distance from the center of the rim to the end of the hub tube in the male (non- valve stem) side.
  • Bearing Style - what type of bearing is needed, ball bearing, bushing, precision bearings, roller or tapered cup and cone bearings?
  • Bearing Size - what is the outside diameter of the axle the wheel is to be installed on?
  • Zerk Fitting - does the wheel require a zerk fitting?


rims-hi-speed-thHigh Speed Trailer Rim

High Speed Rims

High Speed Trailer Rims are designed specifically to handle the normal "wear and tear" of trailer uses. When selecting trailer rims some thought must be given to the load that is to be carried. As a rule of thumb, overall capacity is limited be the component with the lowest capacity or the rated capacity of the axle.

How to Determine a Bolt Circle

  • Wheels and hubs should be matched by the number of bolts and bolt circle.
  • To determine the bolt circle of rims with an even number of bolt holes, measure from the center of one hole, directly across the rim or the center of bolt hole directly across from it.
  • To determine the bolt circle of rims with an odd number of bolt holes, measure from the center of one hole directly across the middle of the rim to a point midway between the two bolt holes directly across from it.
  • An alternative method is to measure the distance from the center of one bolt hole to the center of the pilot hole and multiply that number by two.

Standard Trailer Rim Bolt Circles

  • 4 hole x 4" bolt circle
  • 5 hole x 4-1/2" bolt circle
  • 6 hole x 5-1/2" bolt circle
  • 8 hole x 6-1/2" bolt circle

The dimensions indicated above are for the wheel mounting faces.

How to Determine Rim Offset

  • Positive Offset - the hub mounting surface is the outside of the rim, the tire will be closer to the trailer frame.
  • Negative Offset - the hub mounting face is the inward side of the rim. The tire will be farther away from the trailer frame.