Extra shifter

On ADY the normal shifter is a little limited, being from a boy bike with 24" wheels, then an other gear change has been inserted.
Putting the chain line, from the pedals to the bottom bracket, on the left side it’s possible to use an extra derailleur for three gears.
With this configuration in order to use this shifter “You must pedal in the opposite direction”.
This is not a problem since it is used from time to time in order to choose the modality of: climb, normal or speed.
Indeed it's a comfort, when stopped half of a climb, the possibility to shift down and then restart.

 
Being made in order to be mounted to right, for having a regular operation, the derailleur had to be mounted under to the three gears to be able to work on the “climb” of the chain, then they had to be moved on the pedals, but this would have involved, with problems, the positioning of the tensor and the chain way.     Perhaps it is possible but the game is not worth the candle. 

Turning the pedals group, for having the gear on the left, the pedals have the thread reversed and therefore not self-locking and the same one can happen for dice of implantation of the bottom bracket, them if that one is turned also.
Obviously must be used grains or screws to block them.  

The chain tensor is derived from a shifter “posterior derailleur” modified and the chain guides from gears recovered from a cog-set and mounted on bearings (two for gear).      The two front gears, counter-rotating, have a guide in bakelite in order to avoid fall of chain.

The ratios are 42 / 30-42-52 and 24-34-42 / 14-16-18-21-24-28.   Covered distance every turn of the pedals:  minimum 1,3 m   maximum 8 m.

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