Abstract: An adjusting mechanism of the bicycle brake system is composed of a fastening member, a resilient member and an adjusting member. The fastening member is fastened with one of two brake arms of the bicycle brake system and with the bicycle frame. The resilient member has a deformable arcuate section and is fastened at one end thereof with the brake arm. The adjusting member is composed of an adjustment shaft and a tapered block which is movably fastened with the adjustment shaft such that the tapered block can be actuated to move linearly by the adjustment shaft so as to force the arcuate section of the resilient member to deform.

Abstract: A bicycle two-step brake system is composed of two brake arms having a primary arm and a secondary arm fastened pivotally with the primary arm. The primary arm is fastened with the bicycle frame while the secondary arm is fastened with a brake cable of the brake lever. The primary arms are provided with a first drag portion and a brake shoe capable of being forced against the bicycle wheel rim so as to slow or stop the bicycle in motion. The secondary arms are provided with a second drag portion. Two elastic members are located between the primary arms and the secondary arms such that the elastic members enable the first drag portions and the second drag portions to have an outward bracing force capable of cooperating with a pulling force of the brake cable to cause the primary arms and the secondary arms to act independently or synchronously to bring about the two-step braking mechanism.