Crossing the Pyrenees into Spain involves the longest climb of the journey by some way. It is gently uphill from the start of the day and the last 10-15km of the climb are reasonably steep. It is over 50km to the summit which is also the border between Spain and France. From there it is gently downhill all the way to Ripoll.
Most of the day there is little alternative to the main road, but we did find a detour away from traffic from 3km to 8km. The road (D115) gradually gets less busy as you get further from the coast and by the time the real climbing starts it is fine.
Prats-de-Mollo-la-Preste is the last town before the border and a good place for refreshment in advance of tackling the steep part of the climb: