SRAM internal gear hub shifter on drop bars

[dvt]

Gary Young wrote:
> dvt <[email protected]> wrote in message news:<[email protected]>...
>>Gary Young wrote:
>>>Wouldn't the travel agent be almost the exact size needed for Shimano
>>>7-speed STI levers mated with a 7-speed Nexus hub? Unless my
>>>calculations are wrong (a distinct possibility), the STI lever would
>>>pull about 5% too much cable with each shift. Could you compensate by
>>>filing down the cable track in the travel agent? (I don't have any of
>>>this equipment or I'd try it myself.)

>>Filing down the cable track in the travel agent sounds like it would be
>>a little tricky. You might need a basic machine tool or two (i.e. a
>>lathe or a drill press), and most people won't be interested in that. I
>>wouldn't do it unless I really wanted to use the Shimano hub.

> I was thinking you could just use a needle file to create a flat spot.
> Is there some reason the track has to be concentric and perfectly
> round?

A flat spot would adjust the cable throw in one particular spot, but you
need the cable throw adjusted throughout the entire range of movement.

Even if you could get away with one flat spot to adjust the throw at the
last gear, you would run into problems. For example, it would be a
finicky installation. You would have to be sure that the flat spot is
encountered at just the right place in the gear range. And the
transition from round to flat might cause the cable to fray and wear at
that point. The travel agent already causes a sharp bend in the cable,
so maybe adding another weak spot wouldn't be much of a problem, but I'd
avoid it if possible.

--
Dave
dvt at psu dot edu

 

[Gary Young]

dvt <[email protected]> wrote in message news:<[email protected]>...
> Gary Young wrote:
> > dvt <[email protected]> wrote in message news:<[email protected]>...
> >>Gary Young wrote:
> >>>Wouldn't the travel agent be almost the exact size needed for Shimano
> >>>7-speed STI levers mated with a 7-speed Nexus hub? Unless my
> >>>calculations are wrong (a distinct possibility), the STI lever would
> >>>pull about 5% too much cable with each shift. Could you compensate by
> >>>filing down the cable track in the travel agent? (I don't have any of
> >>>this equipment or I'd try it myself.)
>
> >>Filing down the cable track in the travel agent sounds like it would be
> >>a little tricky. You might need a basic machine tool or two (i.e. a
> >>lathe or a drill press), and most people won't be interested in that. I
> >>wouldn't do it unless I really wanted to use the Shimano hub.
>
> > I was thinking you could just use a needle file to create a flat spot.
> > Is there some reason the track has to be concentric and perfectly
> > round?
>
> A flat spot would adjust the cable throw in one particular spot, but you
> need the cable throw adjusted throughout the entire range of movement.
>
> Even if you could get away with one flat spot to adjust the throw at the
> last gear, you would run into problems. For example, it would be a
> finicky installation. You would have to be sure that the flat spot is
> encountered at just the right place in the gear range. And the
> transition from round to flat might cause the cable to fray and wear at
> that point. The travel agent already causes a sharp bend in the cable,
> so maybe adding another weak spot wouldn't be much of a problem, but I'd
> avoid it if possible.


Yep, I wasn't thinking. Thanks for the explanation.