Patent ID: 8413769

Claim:
A bicycle brake system located across a wheel rim and comprising: a first arm unit having a first pivot portion which is located between a first arm and a first pivotal end, an engaging slot defined in the first pivotal end, a first brake pad connected to the first arm and adapted to face the wheel rim; a second arm unit located in the engaging slot and having a second pivot portion pivotably connected with the first pivot portion, the second pivot portion located between a second arm and a connection portion, a second brake pad connected to the second arm and adapted to face the wheel rim, the first and second arms adapted to be symmetrical to two sides of the wheel rim; a cam unit having a contact piece detachably connected to the second arm unit, a cam member having a pivotal portion pivotably connected to the pivotal end and located in the engaging slot, the cam member including a guide portion and a cam portion on two ends thereof, the cam portion having a curved surface which is in contact with the contact piece; and an operation unit connected to the connection portion and having a cable which extends through an end of the connection portion and is fixed to the guide portion, the end of the connection portion and the guide portion located on a common axis, the cam member and the second arm unit being pivoted by pulling the cable, the contact piece being pushed by the cam member to change a distance between the first and second brake pads.