Abstract: A handlebar assembly for bicycles includes a connection bar having a first end securely mounted to a steerer tube and a recess is defined in a second end of the connection bar. A positioning cap has a concavity defined in an underside thereof and is securely connected to the second end of the connection bar. A pad is connected to an inside of the concavity of the positioning cap and a handlebar is securely engaged with the concavity of the positioning cap and the recess of the connection bar. Bolts extend through the positioning cap, the pad and are threadedly engaged with threaded holes defined in the connection bar.

Abstract: A combination of a bearing journal assembly and a head tube of a bicycle includes a skirt extending from each of two ends of the head tube and each skirt has a groove defined therein. A retainer has a plurality of balls rotatably engaged therewith as a one-piece member which is engaged with the groove in each skirt.

Abstract: A handlebar assembly for bicycles includes a handlebar stem and a clamping member is connected to the handlebar stem. A handlebar extends through the clamping member and a relief sleeve is mounted to the handlebar and sandwiched between the handlebar and the clamping member. The relief sleeve has holes which release stress applied to the handlebar.

Abstract: A bottom bracket assembly includes an axle with two flanges on an outer periphery close to a first end of the axle and two bearings are mounted to the axle and engaged with the two flanges. A flange extends from the outer periphery of the axle and is located close to a second end of the axle. A bearing is mounted to the axle and engaged with the flange. Each bearing is retained by a retaining ring such that the axle is rotated smoothly.

Abstract: A head set assembly for bicycles includes a bearing set with balls received between an upper race and a lower race which is connected to an end of a head tube of a bicycle. The upper race has an annular inclined surface and an annular vertical inside. A pressing ring has an inclined outer surface for being engaged with the annular inclined surface of the upper race, and a flange extending from the inclined outer surface. The flange of the pressing ring is matched with the annular vertical inside of the upper race. The flange is mounted to a steerer tube extending through the head tube. A dust cap is connected onto a top of the pressing ring and a skirt of the dust cap encloses the lower race of the bearing set.

Abstract: A method for making a hollow crank includes a three-direction forging step to forge a piece to have a recess in a first end of the prototype; a step of forming a hollow first end of the prototype by forcing the first end through a cone-shaped passage in a mold; a step of forming the first end of the prototype to have an angle relative to the second end of the prototype; a step of setting the first end of the prototype in a cold-forging mold to set the shape of the prototype.

Abstract: A method for making a hollow crank includes a three-direction forging step to forge a piece to have a recess in a first end of the prototype; a step of forming a hollow first end of the prototype by forcing the first end through a cone-shaped passage in a mold; a step of forming the first end of the prototype to have an angle relative to the second end of the prototype; a step of setting the first end of the prototype in a cold-forging mold to set the shape of the prototype.

Abstract: A handlebar stem structure includes a tube having two connection members and two extensions are movably connected to the two connection members. Each of the two extensions has two connection ports. An outer layer is coated to the tube and the connection members, wherein the connection ports extend from the outer layer and a first recess is defined in the outer layer. A retaining member is connected to the two connection ports and a second recess is defined in an inside of the retaining member. The first recess and the second recess are matched to form a passage for receiving a handlebar.

Abstract: A head set assembly for bicycles includes a bearing set with balls received between an upper race and a lower race which is connected to an end of a head tube of a bicycle. The upper race has an annular inclined surface and an annular vertical inside. A pressing ring has an inclined outer surface for being engaged with the annular inclined surface of the upper race, and a flange extending from the inclined outer surface. The flange of the pressing ring is matched with the annular vertical inside of the upper race. The flange is mounted to a steerer tube extending through the head tube. A dust cap is connected onto a top of the pressing ring and a skirt of the dust cap encloses the lower race of the bearing set.

Abstract: A crank arm for bicycles includes two end pieces and a hollow tube connected between the two end pieces. Each of the two end pieces has an engaging hole defined therethrough and an insertion which is inserted in respective one of two ends of the hollow tube. A compound material layer is coated to the outside of the two end pieces and the hollow tube.

Abstract: A handlebar stem structure includes a tube having two connection members and two extensions are movably connected to the two connection members. Each of the two extensions has two connection ports. An outer layer is coated to the tube and the connection members, wherein the connection ports extend from the outer layer and a first recess is defined in the outer layer. A retaining member is connected to the two connection ports and a second recess is defined in an inside of the retaining member. The first recess and the second recess are matched to form a passage for receiving a handlebar.

Abstract: A crank arm for bicycles include a crank body having two bases on two ends thereof and each base has a threaded hole. A plurality of extensions extend from one of the bases and each extension is connected to a connection member. A resin layer is coated on the crank body and a carbon fiber layer is coated on the resin layer. The connection members extends from the resin layer and the carbon fiber layer so that a chainwheel is connected to the connection members by rivets or bolts.

Abstract: A bicycle chain guide device includes a plate mounted to the crank axle has two protrusions and each of the protrusions has a first roller and a second roller connected thereto. The chain engaged with a chainwhell passes between the first roller and the second roller on each of the two protrusions.

Abstract: An adjustable bicycle chain guide device includes a plate mounted to a crank axle and the plate has two protrusions. Two rollers each have an extension and the two extensions are respectively connected to the two protrusions. Each of the extensions has two holes defined therethrough and each of the protrusions has two rows of positioning holes so that the positions of the rollers are adjusted on the protrusions by engaging bolts with different positioning holes.