The Chiliad Challenge is a side mission in Grand Theft Auto: San Andreas. The mission is started by entering a parked Mountain Bike on top of Mount Chiliad between 7:00 and 18:00 and having a cycling skill above 40%. The goal of the mission is to be the first to reach the base of the mountain while racing with other mountain bikers down the mountain. There are three courses that need to be completed for 100% completion. All three courses share the same finish zone and the final sector.
Whereas in any other vehicle race wherein one can shoot at other contestants and get away with it, in this muscle-based race, if the player attempts to shoot opponents, not only will the player fail the mission, a one wanted star will also be obtained. Typically though, trying the race again at the top of the mountain will help lose the cops. The player can, however, get off and use the sniper rifle (no other weapon can be used) to eliminate them without penalty.
- Scotch Bonnet Yellow Route: (Reward: $500) This route lays mostly in the southwestern face of the mountain; it is the shortest way down to Angel Pine in distance and time but it is also the steepest, and corners are very closed (almost 180º most of them) and tricky due to the reduced grip of the dirt track and the descending factor. A careful braking and cornering is the key, and little sprinting is used. There are plenty of places where CJ can fall off the road and down the mountain from great heights, but some of them are protected with fences. Once this event is won you gain access to the next event.
- Birdseye Winder: (Reward: $1,000) This run uses the north face route to descend and then turns along the west side and then south down to Angel Pine, it is longer and less steep downhill overall than the previous route but also has some long and leveled straight sectors where CJ can sprint for a while and take the lead easily. However, side protections are even less than in the previous event and there are still some difficult corners. Once this event is won you gain access to the next event.
- Cobra Run: (Reward: $2,000) This race will start mid-way down on the south side and follow a narrow trail which is very tricky in the beginning, with an elevated part; after a jump the second half allows a higher speed as it's wider.
- While in The Chiliad Challenge, get off of your bike and jump off the mountain. Then open a parachute, the game will return you to your bike, but you will still have an open parachute on your back. The parachute then loses all of its function as a parachute. The video can be seen here on YouTube.
- In the first two races, you can block the entrance into the downhill path with the Camper or Journey. It will still be parked there after these races started and all or most of your competitors will bump into this barricade and fall off their bikes. This will get you in the pole position and makes things much easier.
- This technique is a lot more dirty and involves using the sniper rifle. Let all the racers pass the finish line (but do NOT cross the finish line checkpoint yourself) and dismount from your bike (beware of the timer message telling you to get back on the bike). Now use the sniper to kill all of the racers as you will not get disqualified from the race for using a sniper rifle. Once all have been killed, you will notice that you are in first place. Simply cross the finish line and you have won. This works for all three races. A video showing this can be seen here on YouTube.