Some San Francisco Bay Area mountain bike related cool links:

Trails do get closed due to irresponsible riders, here is IMBA Rule of the trails:

    1. Ride on open trails only.
    2. Leave no trace.
    3. Control your bicycle!
    4. Always yield trail.
    5. Never spook animals.
    6. Plan ahead.

It's all about ridings  but here is my MTB specs.

Some pictures from local trails:

Alviso Wildlife Refuge - I bike here during lunch time, couple times a week.

Mission Peak - I bike here at once a week.

This little park is right next to my home

Lick Observatory, nice climb on road bike from Quimbee Road

Auburn SRA - nice single tracks

Fremont Older - These pictures were taken in 1999, I lost track of these old riding buddies