Mountain biking/hillwalking in Madrid

I'm looking for some like minded folks to go hill walking and/or mountain biking in the mountains north of Madrid. I'm not sure if there are any clubs for that kind of thing, my Spanish is pretty poor so would be great to meet some English speakers who are into the outdoors and pints afterwards.
I'm free every other month for the entire month, so flexible with going a wander weekends or week days.

Hi Fergin
I´m actually living in Scotland but I´m from Madrid .
I love walking in the if you are still interesting,let me know.
Thank you