1. Three Basic Dimensions
Pitch, Roller Diameter and Inner Width are known as the “Three Basic Dimensions of Roller Chain.” When these three sizes are similar, roller chains and sprockets are dimensionally compatible.
2. Basic Parts
Link Plate
The plate is the component that bears the tension placed on the chain. Generally this is a repeated loading, occasionally accompanied by shock. Therefore, the plate must not only have got great static tensile strength, it must also hold up to the dynamic forces of load and shock.
Pin
The pin is at the mercy of Transmission Chain shearing and bending forces transmitted by the plate. At the same time, it forms a load-bearing part (together with the bush) when the chain flexes during sprocket engagement. Therefore, the pin needs high tensile and shear power, resistance to bending, and must have sufficient endurance against shock and use.
Bush
The bush is at the mercy of complex forces from all parts, especially from the repetition of shock loads when the chain engages the sprocket. For that reason, the bush needs extremely high shock resistance. In addition, the bush forms a load-bearing part together with the pin and therefore requires great wear level of resistance.
Roller
The roller is subject to impact load as it mates with the sprocket teeth during engagement of the chain with the sprocket. After engagement, the roller changes its point of contact and stability. It is held between the sprocket tooth and bush, and progresses the tooth face while receiving a compression load. For that reason, it must be resistant to put on and still have power against shock, exhaustion and compression. (RS25 and RS35 are bush chains , nor have rollers).
Roller Link
Two bushes are press 
fit into two roller link plates and rollers are inserted to allow rotation around the exterior of the bushes during operation. This is the same for solitary and for multi strand chains.
Pin Hyperlink and Intermediate Plate
The pin link includes two pins that have been press match two pin link plates. In case of multi-strand roller chain up till size 08B, an intermediate plate is certainly added to the pin link. In the event of multistrand roller chain above size 08B, two intermediate plates are added to the pin hyperlink. The intermediate plates are slide fit for regular roller chain and press match for Extremely roller chain.