lengthy glueing and curing process so a rider can have a large selection of tires at their disposal. Until recently, clinchers also generally had more cutting edge tread patterns than the more traditional tubulars. Some enthusiasts even went as far as to send Michelin Mud tires (a popular clincher tire) to Dugast (a manufacturer of high end tubular tires) to have a modern tread pattern incorporated into a traditional tubular. However, since 2005 several tubular manufacturers have designed more modern style tread patterns, namely Dugast with its Rhino, Tufo with its Flexus and Challenge with its Grifo and Fango. Lastly, clincher tires generally cost less than tubulars. Because cyclo-cross season spans autumn/fall and winter, course conditions can vary quite drastically. Often racers have at least dry and wet weather tires to choose between. Dry tires tend to have much smaller, closely spaced tread such as the diamond pattern for low rolling resistance. Wet weather tires have larger and more widely spaced knobs to aid in grip and mud shedding. Tires do not usually vary in width a great deal due to the theory that a narrow tire has the least rolling resistance (for dry courses) and that it will also cut through mud to the harder ground underneath (for wet/muddy courses). Although widths below 30c were popular in the past, current tires tend to be available from 30-35c with 32 and 34 being the most common. Equipment choice Because ground conditions can vary greatly, equipment choice is extremely important. Add to this the fact that the races are relatively short and that equipment changes are allowed during races and equipment selection can get fanatical. Since tubular tires are popular in professional and some amateur racing and tires cannot easily be removed from the rim, collections of wheels with tires installed, are required for the varying conditions. It is common for racers even at an amateur level to have a pair of race bikes (one to ride and one in the pits as a back-up) and several wheels to choose from. At the professional level it is essential to have several bikes and wheel options available. More recently, tubeless clincher tires have become popular after their successful presence on mountain bikes for the last several years. Advantages include lower overall wheel weight (no inner tube), lower tire pressures allowing for more traction without risk of a 'pinch flat' and no glue