Chain wheels confirmation.
One spline is made narrower than the other splines. This is done to prevent incorrect assembly of the sprockets.
Due to the switching on the sprockets, the sprockets should be mounted at a fixed location with respect to each other.
The chain wheels are kept at the appropriate distance by spacers.
The chain wheels can be locked in two ways:
- The smallest sprocket is screwed onto the outer housing of the freewheel.
- By a special locking ring that is screwed into the outer housing of the freewheel.
To unscrew the smallest sprocket Special tools are required (Fig. 67).
The tool is available in different versions but the principle is the same.
With a lever with a piece of chain the outermost chain wheel is held.
Another lever with a piece of chain is wrapped around the smallest sprocket.
The smallest chain wheel can then be unscrewed with this lever, while the other lever holds back the freewheel.
The smallest chain wheel can then be turned back on the freewheel by hand.
The driving force then secures him firmly.
If the sprockets are secured by a locking ring, it can be loosened with a special nut.
The freewheel must again be held with a lever with chains.
When tightening the locking ring, it is important that this is done with the correct torque.
When the locking ring is too loose or too tight, this may affect the performance of the index system, especially when using plastic spacers.
Moreover, the self-locking ring is very difficult to unscrew if it is firmly put too tight.
When a customer wants to increase the number of rear sprockets from 7 to 8 or 8 to 9, there must be paid attention to the following points.
- The switch and the index derailleur system should also be adjusted.
- In the case of 7- to 8-speed is to be mounted there is a different freewheel.
When mounting a different freewheel to the rear wheel it needs to be re-centered.
- The installation width changes when expanding 7- to 8-speed. 7-speed mountain bike cassette hubs have an installation width of 130 mm, speed 135 mm. -speed racing to an installation width of 126 or 130 mm.
If the installation width is different, then there will have to be installed a new frame.
- The bending that happened earlier, is now no longer allowed. This is especially true for aluminum bicycles . The thin tube walls of a rear fork can break spontaneously.
- In an extension of 8- to 9-speed there must be a 9-speed chain (narrower) to be mounted.