The Sentiero Rusca starts from the centre of Sondrio and, after passing the terraced vineyards, climbs up to Chiesa in Valmalenco.
Climbing the route, the altitude difference is remarkable (about 700 metres), therefore you must be properly trained. Besides mountain bikes, "traditional" bikes can be used.
Obviously, there are no problems going the opposite direction, from Chiesa Valmalenco to Sondrio. From Chiesa in Valmalenco, the most trained and adventurous cyclists may decide to reach the Muretto Pass, the ancient way connecting Valtellina and Engadine.