Rules define the difference between a cyclo-cross bike and a mountain bike
4.3 Comments on article 1.3.020
For massed-start road races and cyclo-cross, the frame elements (arranged as shown in the diagram below) shall
be tubular without excessive curvature (a straight line along the element’s longitudinal axis must remain inside
the element). The elements shall have a maximum transverse dimension of 8 cm and a minimum transverse
dimension of 2.5 cm (reduced to 1 cm for the seat stays, chain stays and forks). If the seat tube is extended so that
it replaces the seat post, the anchorage point with the top tube is considered for the purposes of the horizontal
template of the “Shape 1” diagram shown in article 1.3.020.
3.2.3 Technical specifications
Except where stated to the contrary, the following technical specifications shall apply to bicycles used
in road, track and cyclo-cross racing.
The specific characteristics of bicycles used in mountain bike, BMX, trials, indoor cycling and paracycling for riders with disabilities are set out in the part regulating the discipline in question.
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