If you’ve been reviewing bike parking guides or bike parking standards, you have probably come across standard or inverted u bike rack specifications. Somewhere in the typical bike rack description, a specification may state that the bike rack is 1.9”OD Schedule 40 tubular steel, 24” wide by 36” high. On first glance, you could conclude that bike racks involve bending tubular steel. No rocket science there, but if you’re interested in reference points that you can understand, this may help. However, if you’re researching artistic or non-standard bike racks, you’ll find a different set of specifications.
Either round or square tubular steel is the material of choice for making inverted u or standard bicycle racks. The tubular steel is further defined either by its diameter or nominal dimension. The tubular dimensions may be listed as 1.65” od, 1.9” od or 2.375” od. The “od” stands for outside diameter which is the exterior cylindrical surface of the tube. The nominal dimension of 1.65” od is 1-1/4”, 1.9” equals 1-1/2” od and 2.375” od is the equivalent of 2”. Wouldn’t you agree that the nominal dimensions are more understandable than the od dimensions.
The pipe schedule identifies the wall thickness of the tubular steel. That dimension is static with the outside or nominal dimension of the tubular steel. For example, the wall thickness of a 1.9” od schedule 30 pipe is .125 inches thick, whereas a 1.9” od of a schedule 40 pipe is .145” or .20 inches thicker that the schedule 30 pipe.
Another component of an inverted u bike rack description that is sometimes confusing is the width. There’s the outside to outside dimension, or a center to center dimension and the overall rack dimension. The outside to outside dimension relates to the width of the rack from outside column edge to outside column edge. The center to center dimension relates to the bike rack width from the center point of column A to the center point of the column B. The center to center dimension is commonly used to define the bending radius. The overall dimension is outside edge to outside edge of the bike rack components.
Hopefully this explanation will help the next time you’re looking at a variety of different bicycle specifications.