How does a IGH freewheel work ?

[qwerkus]

Hello,

Not sure if it's the right section. Can anyone explain or point to a good source where it is explained how the freewheel of an alfine 8 or a nexus inter 3 IGH work ? Would it be possible to remove it, to allow back-pedalling (and mid drive regen!) I've been looking around, and only found contradicting stuff.

Any help would be much appreciated.

 

[spinningmagnets]

The Sturmey and Nexus 3-speeds use large pawls...The Alfine-8 has a cpouple of models, some use p[awls, and the upgraded models use roller-clutches, which run very quietly when freewheeling (instead of clicking)...

https://www.electricbike.com/mid-drive-kit-igh/

 

[qwerkus]

Thanks for the reply. So am I correct to assume that there is not 1 freewheel, but (at least in a 3 speed config) 3 - one for each gear ?

 

[amberwolf]

No, still just one, on the input from the sprocket itself. Take a look thru some of these service manual / exploded diagrams and you may get the idea:

https://www.google.com/search?q=igh+exploded+diagram&num=100&newwindow=1&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjYlIb5yLHbAhUREawKHeR8CIoQsAQIKg&biw=747&bih=798

There's some stuff here too:
https://hubstripping.wordpress.com/\
https://www.sheldonbrown.com/sturmey-archer_3-spd.html

 

[qwerkus]

Is this correct ?

 

[Chalo]

I would not expect a gearhub to shift right, or at all, without its overrunning mechanism.