Shimano Positron Gears

[Andy in Germany]

This is more in hope than expectation as the Positron system is pretty obscure. However...

A customer brought a bike with a Positron system for repair; the rear mech had been caught in the spokes and bent out of shape so the wheel wouldn't turn. I replaced the old one with another found in our spares department (Note to self: make a "positron" box) and now it either doesn't index properly in the upper gears, or it also brushes on the spokes.

Also, this looks wrong to me:

However I can't turn the mech so it is in a more 'Normal' position, and for all I know Positron mechs may look like that; Information is hard to come by.

Can anyone with experience of the system advise:

1: How to stop the mech pulling into the wheel and
2: Is that mech correctly positioned, and if not how should it be?

Thanks in advance...

 

[Paulus]

This is more in hope than expectation as the Positron system is pretty obscure. However...

A customer brought a bike with a Positron system for repair; the rear mech had been caught in the spokes and bent out of shape so the wheel wouldn't turn. I replaced the old one with another found in our spares department (Note to self: make a "positron" box) and now it either doesn't index properly in the upper gears, or it also brushes on the spokes.

Also, this looks wrong to me:

View attachment 666209

However I can't turn the mech so it is in a more 'Normal' position, and for all I know Positron mechs may look like that; Information is hard to come by.

Can anyone with experience of the system advise:

1: How to stop the mech pulling into the wheel and
2: Is that mech correctly positioned, and if not how should it be?

Thanks in advance...

Is this any help?


View: https://youtu.be/S-78NkQb47M

 

[Andy in Germany]

Is this any help?


View: https://youtu.be/S-78NkQb47M

Hehe, that's the video I used to figure how to set them correctly. THe derraileur in the vid looks more like a "normal" Shimano derailleur than mine though, which makes me think there could be a problem there as well.

 

[classic33]

Any help?
The page linked to in this thread cannot be found.
www.cyclechat.net/threads/shimano-positron-5-speed-derailleur

Instructions on setup available at
https://www.disraeligears.co.uk/site/shimano_pps-fh_-_instructions.html

https://disraeligears.co.uk/site/shimano_-_positron_instruction_manual.html

 

[figbat]

Is the hanger or derailleur bent?

 

[Andy in Germany]

Any help?
The page linked to in this thread cannot be found.
www.cyclechat.net/threads/shimano-positron-5-speed-derailleur

Instructions on setup available at
https://www.disraeligears.co.uk/site/shimano_pps-fh_-_instructions.html
View attachment 666233


https://disraeligears.co.uk/site/shimano_-_positron_instruction_manual.html

Helps a lot, thanks.

 

[Andy in Germany]

Is the hanger or derailleur bent?

The previous one was, but as far as I can tell, this was straight

 

[Andy in Germany]

Looking at the instructions, I think the cable may be too short. Either way I've reached the point where the customer will have to decide what she wants as the extra work required will start to get expensive.