To maximize chain life, some forms of chain adjustment must be provided.
Moving one of the shafts or by using jockey sprocket is useful for chain adjustment.An adjustable jockey sprocket engaged with unloaded strand of chain is suggested if the shaft movement is impossible, as diagram followed. Normally, the jockey should have the same number of teeth as the driver sprocket not less than the smallest sprocket and ensure that the speed does not exceed the maximum rating shown. Several sprocket can be used on a single drive. Adjust the chain according to the needs.
Precautions for chain adjustment:
1 The chain should be adjusted regularly so that one strand tight the slack strand can be moved a distance of “F” （previous posts）at the mid point.
2 To cater for any eccentricities of the mounting, the adjustment of the chain should be tried through a complete revolution of the large sprocket.
3 Adjustment is achieved either by the movement of one of the shafts or by using of the jockey sprocket.
The amount of the adjustment provided by either method should be sufficient to take up chain wear amounting to two pitches or less than two percent elongation above nominal chain length.
When used for adjustment, a jockey should be positioned on the unloaded side of the chain, preferably nearer to the driven sprocket and gearing with the outside of the chain. It should have an initial chain lap of at least four teeth and a free length of chain not less than four pitches between it and the nearest sprocket.
All mounting for jockeys should be rigid and when manual chain adjustment is provided, the moving member must be securely locked in position after adjustments have been made. In a word, the chain adjustment should respond to the different forms.