The climb from the west to the Puerto de Cerredo is relatively long (14.6 kilometers) for the 549 meters in altitude that are overcome, so the gradient is only 3.8%, on average. The ride begins at the T-junction of the AS-212 and the AS-15. The first 9.5 kilometers to Zarréu (in Asturian; Cerredo in Spanish) are not very strenuous (largely 0-4%). At the end of the built-up area of Zarréu, there are some buildings used (in the past?) for mining. From here to the pass still 5 kilometers are left, which are somewhat steeper (5-7%) than the kilometers before Zarréu.