Old Shimano friction shifter question

I've got a lovely set of old Shimano downtube shifters (actually stem mounted originally) with
aluminum levers - very nice looking compared to the plastic and tin ones that came later. However, I
have a few questions.

The right (RD) and left (FD) mechanisms are completely different - the left being a simple set of
plastic disks supplying friction, while the right has a notched metal disk, a small washer, and a
single plastic disk. The metal disk fits over a nub inside the lever's central cavity, and as the
nub is smaller than the notch, there's a bit of slop to the lever.

1) Will this go away once cable pressure is applied?

2) Why so complicated a design?

Any help greatly appreciated.

 

The right lever (rear derailleur) was designed to float back a bit after shifting, and the
derailleur had (as they still do) a floating upper wheel to track the cog. The idea is that you pull
the lever back to shift to a larger gear, overshifting a bit as you do, and, when you let the lever
go, it floats into place. As I recall, they actually worked OK.

--Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

"Brian Huntley" <[email protected]> wrote in message news:[email protected]...
>
> I've got a lovely set of old Shimano downtube shifters (actually stem mounted originally) with
> aluminum levers - very nice looking compared to the plastic and tin ones that came later. However,
> I have a few questions.
>
> The right (RD) and left (FD) mechanisms are completely different - the left being a simple set of
> plastic disks supplying friction, while the right has a notched metal disk, a small washer, and a
> single plastic disk. The metal disk fits over a nub inside the lever's central cavity, and as the
> nub is smaller than the notch, there's a bit of slop to the lever.
>
> 1) Will this go away once cable pressure is applied?
>
> 2) Why so complicated a design?
>
> Any help greatly appreciated.

 

Mike Jacoubowsky wrote:
> The right lever (rear derailleur) was designed to float back a bit after shifting, and the
> derailleur had (as they still do) a floating upper wheel to track the cog. The idea is that you
> pull the lever back to shift to a larger gear, overshifting a bit as you do, and, when you let the
> lever go, it floats into place. As I recall, they actually worked OK.
>

Excellent! Thanks, Mike. That makes wonderful sense now.