The chain line
- chainring and sprocket must lie parallel to the frame plane.
- chainring and sprocket must have the same distance to the frame plane.
The chain line is correct, if:
The chain line can be checked by seeing if the chain line of the chain wheel is located in a line with the chain line of the chain wheel. Shiny wear spots on the inside of the chain and to the teeth of the sprocket wheels indicate a misalignment of the chain.
In a derailleur system we check the chain line with a catenary-checker on the following issues:
- A crooked mounted rear sprocket.
- An oblique position of the rear sprocket because to the is inconsistent rear frame.
- A wobble in the chainring.
A simple way to determine the chain line of the chain wheel is as follows. Measure the distance between the left side of the seat tube and the outside of the outer chain ring. Then, measure the distance between the right-hand side of the seat tube to the inside of the inner chainring. Add these values and divide them by two, the result gives the chain line for the chain wheel again.
The chain line of the chain wheels (pinion) can be adjusted by both to measure the width of the chain wheel as the distance between the smallest sprocket and the inside of the right pad. Measure as last, the installation dimension of the hub. Subtract the installation dimension of the width of the sprocket and divide the value found by two. Subtract this, the distance between the smallest sprocket and inside right path. You have now calculated the chain line of the sprocket.
If the values of the line for the chain sprocket, and chain wheel match is the chain line in order.
The distance from the chain wheel can be measured by measuring the installation dimension of the hub (dimension A) and to measure the distance of the sprocket wheel until the right-locking nut (size B). the distance to the frame plane is then 1/2 A – B. is to measure the distance of the chain blade to the frame plane by measuring the width of the lower tube (size C), and to measure the distance between chain wheel and left side of the down tube ( size D). the distance to the frame plane is then D – 1/2 C (Figure 64) . The distance from the chain wheel to the frame plane can be changed by moving between the rings and / or by the sprocket wheel to rotate. This allows the chain to vary line is approximately 10 mm. The distance from the chain wheel can be changed by mounting a different crank or, as the crank shaft is mounted with adjustable distance chain, to shift the crankshaft relative to the frame. The chain line is corrected most easily by changing the position of the sprocket . (Figure 65).
In bicycles with derailleur gears, the chain line is determined by measuring the distance of the middle chain wheel to the frame plane (in the case of an odd number of chain wheels), or by measuring the distance between the middle two chain wheels to the frame plane (with an even number of chain wheels).