The best option to participate in the Houffa Gravel is a gravel bike. This may have gravel handlebars, standard race handlebars or straight handlebars. A mountain bike is also allowed in the Houffa Gravel. An e-bike is allowed in the free starts but prohibited in the mass start as part of the UCI Gravel World Series. So, for the Houffa Gravel you have several options. If your result in the Houffa Gravel qualifies you for the World Championships Gravel, it is mandatory to ride a gravel bike there.