The plate is the component that bears the tension placed on the roller chain during transmission. Usually this is a repeat load, sometimes accompanied by shock. The plate must therefore have not only great static tensile strength, but also high fatigue strength, impact strength, and dynamic toughness. The pin is subjected to shearing and bearing forces transmitted by the plate. At the same time, it forms a load-bearing part, together with the bushing, when the chain flexes during sprocket engagement. Therefore, the pin needs wear resistance other than shear strength, bending strength and toughness. The bushing is subjected to complex forces from various parts. It must have high impact fatigue strength, as it bears repeated shock load, especially when the chain engages the sprocket. Acting as a bearing when coupled with the pin, it must have wear resistance. The roller is subjected to impact load repeatedly as it strikes the sprocket teeth during chain engagement with the sprocket. After engagement with the sprocket, equilibrium position of gear engagement changes depending on tension. The roller, therefore, is subject to stress load and friction when it is sandwiched between the gear and the bushing and rotates over the tooth surface. It therefore requires shock fatigue strength, proof compressive strength, and wear resistance. RS11, 15, 25, and 35 chains do not have rollers. Two bushings are press-fitted into two roller link plates so that the roller can rotate outside the bushings. The same inner link is used for both single and multi-strand chains. For the outer link, two pins are press-fitted into two outer link plates. For multi-strand roller chain, the middle plate is added to the pin link. Slip fit middle plates are used for standard RS Roller Chain and press fit middle plates for SUPER Roller Chain. The basic three dimensions of roller chain are pitch, roller diameter, and inner link inner width. The roller chain and the sprocket are dimensionally interchangeable when the dimensions are identical. In a clearance fit, the shaft and the hole will always have a space or clearance when assembled. This occurs when the tolerance zone of the hole is completely above that of the shaft (pin or bushing). In a press fit, the shaft and the hole will always have interference when assembled. This occurs when the tolerance zone of the hole is completely below that of the shaft (pin or bushing). 　The spring clip, cotter pin, and spring pin are important parts in preventing the connecting link plate from 　dislocating and maintaining chain strength. These parts must be assembled. Generally, roller chain is used either endless with many links or fixed end. Both need a connecting link (special connecting link for lifting). If the roller chain has an odd number of links, an offset link can be used. The chain, however, must be designed with even links when possible. For the OL, make allowances for a decrease of 35% in kW rating (kW) and maximum allowable load (kN {kgf}) compared to the chain itself. For the 2POL, the pin and the offset link plate are press-fitted and riveted, and can be used as per the kilowatt ratings table.