Classic roller skis are longer and have wider wheels and smaller diameters for easier balance with a ratchet in either the front or the rear wheel to provide kick.  When considering classic roller skiing it is import to note that there is less ankle support then there is on a skate boot.  Additionally, classic wheels are made with a wider rubber wheel provide additional support.  When classic skiing the technique used is insuring the skis run parallel in a forward and backward motion.

Classic roller skis are perfect for developing the arms and core strength needed to improve on snow classic performance but their “perfect kick” can lead to learning poor kicking form.  Getting a kick while striding on snow requires strong technique, including good weight transfer, and this is not necessarily a requirement for classic roller skiing.  

Elite skiers almost always select lightweight roller skis with hard rubber wheels designed for smooth surfaces, with either an aluminum or composite shaft depending on the intensity and length of workout.  In general, aluminum roller skis are more durable but are less effective at absorbing road vibrations, while composite roller skis provide the most realistic “snow feel,” but can break if repeatedly bottomed out.