USAT does not govern “Fat Tire” type bikes and leaves it up to the Race Director to determine what is legal at each event. All Fat Tire bikes must meet all USAT biking rules in addition to those set by DRC Sports. The DRC Sports determination and reasons are explained below (Click image for a larger picture) The image displayed is an example of an unacceptable to be considered for the Fat Tire Category:
In order for a bike to be considered fat tire it has to have "knobby" or heavily grooved tires. If the tire is a "slick" or "Road Type" tire, then it is not considered a Fat tire. This classification was created for those who could not afford to buy a road or tri type racing bike. It was created for Mountain Bikes and Beach Cruisers, who could simply not compete with the lighter and faster bikes and allowed them a category with a level playing field for other athletes who had similar equipment.
Fat Tire bikes must have a tire with Knobs over the entire tread.
Hybrids of today are much closer to a conventional "Tri" bike, than they are a Mountain bike. Handlebar drops and slick tires create a bike with a very low weight and rolling resistance. Therefore, it is determined that these bikes do not qualify for "Fat Tire" division and should be used in the Age Group classification.