A seat frame for a motorcycle includes a plurality of aluminum parts manufactured with different manufacturing methods. A seat frame includes front members, middle members, and a rear member, the front members, the middle members, and the rear member being formed of aluminum. The rear member is formed by integral molding based on a gravity casting method. The rear member includes a pair of left and right rail portions, a front cross portion, a rear cross portion, and a plurality of attachment bosses for attaching other parts. The left and right rail portions each have an attachment portion to be connected to a rear end portion of corresponding one of the middle members provided on an end portion thereof on the front side in the vehicle longitudinal direction.

Disclosed is a multifunctional foldable children's tricycle and its operating method, which includes a front frame and a rear frame connected by a main beam. A front directional wheel is provided on the front frame of the tricycle; a steering handle and rear wheels are provided on the rear frame of the vehicle. The steering handle is connected to the front steering wheel by a synchronous wire rope linkage assembly (1). The synchronous wire rope link assembly (1) comprises a guide block and a front guide piece, and guides and limits the wire rope through the guide block and the front guide piece. The multi-functional foldable children's tricycle has a simple structure, more stable steering operation and convenient folding.

A bicycle apparatus comprising a front wheel, an elongated fork having a first end and a second end, wherein the front wheel is attached to the second end of the fort, a handle bar, wherein the handle bar is freely attached to the first end of the fork to allow a rider to steer the bicycle, a frame attached to the fork distal to the first end, a rear wheel attached to the frame, a drivetrain, wherein the drivetrain is connected to the frame and the rear wheel and allows the rider to propel the bicycle forward, wherein, the plurality of elongated tubes of the frame position the handle bars relate to the drivetrain so that a rider is in the orthostatic position.

A bicycle apparatus comprising a front wheel, an elongated fork having a first end and a second end, wherein the front wheel is attached to the second end of the fort, a handle bar, wherein the handle bar is freely attached to the first end of the fork to allow a rider to steer the bicycle, a frame attached to the fork distal to the first end, a rear wheel attached to the frame, a drivetrain, wherein the drivetrain is connected to the frame and the rear wheel and allows the rider to propel the bicycle forward, wherein, the plurality of elongated tubes of the frame position the handle bars relate to the drivetrain so that a rider is in the orthostatic position.

A bicycle frame with a hidden battery pack has a tube member and a battery pack. The tube member is hollow and has a peripheral surface, a receiving space, and a replacement opening. The receiving space is formed inside the tube member. The replacement opening is defined in the peripheral surface of the tube member and communicates with the receiving space. The battery pack is mounted in the receiving space and has multiple batteries. Each two adjacent batteries of the multiple batteries are connected to each other and are able to rotate relative to each other. Each battery of the multiple batteries is capable of being rotated or swung to pass through the replacement opening.

A bicycle frame unit for constructing a bicycle frame has two half casing parts and an annular supporting element. The annular supporting element is connected between the half casing parts and has a connecting hole for matching an outer contour of an external post. A gap is formed between the half casing parts and the annular supporting element, and a connecting material fills the gap and connects the half casing parts and the annular supporting element. A manufacturing method of the bicycle frame unit is also provided.