Biking the Camino de Norte

I can't answer most of your questions, but I would take a small backpack to carry the valuables around when you are off the bikes. Buen Camino, SY

hello,
i did the camino de norte with bicycle and walking.
on bici around 90 - 100 km a day is possible. i have on my bici 2 bags in front, one on the top and 2 in the back. all waterproof.
i can`t remember i ever lock my bike, lol
some alberge are welcome pilgrims with bici some not, than i ask people nearby if i can stay with my tent in there garden, very welcome.
if you book a place you have to arrive, but you never now.
on trail if is possible, but always good to know a way on the road.
take care on the way, buen camino

Most private albergues take bikes, the advantage is you can ring ahead. The Albergue de Peregrinos in Irun takes cyclists, Islares, Aviles, Baamonde, Sobrado dox Monxes do as well, there is a probably a few more locally or association run ones who do as well. You usually have to wait in these non profit albergues until they are sure they will not have more walking pilgrims. Cyclists and walkers do share some of the route, but there is places where cyclists are recommended to take alterative ways, usually due to the Camino not being suitable for bikes.
I have not cycled it but know a few people who have, give yourself a lower km average for the Basque country (or to Bilbao).

I have only seen one cyclist come of their bike and that was the stage leading to Gijon, if you go that way be careful there is a rough forest track going downhill, she nearly went over the edge of a dropoff and she had to ground herself to stop it.

And

Buen Camino