2002 CF: 2004 from Paris: 2006 VF: 2007 CF: 2009 Aragones, Ingles, Finisterre: 2011 X 2 on CF: 2013 'Caracoles': 2014 CF and Ingles 'Caracoles":2015 Logrono-Burgos (Hospitalero San Anton): 2016 La Douay to Aosta/San Gimignano to Rome:
I don't know of any bike stores in San Sebastian but you could consider hiring a bike rather from Tour 'n Ride in Santiago.
Tour’n’ride will ship their bike to you, and then you bike it back to them. Bike rental with a twist!
This is one of the services that Tour’n’ride can offer for pilgrims that do not want the hassle with traveling with their bikes on planes, trains and busses. They will ship the bike with SEUR (the FedEx of Spain), you pick it up and bike the bike back to Santiago and return it there.
Please see their website for prices and for more details regarding the services of Tour’n’ride. You will find them at: http://www.tournride.com/