old Shimano bar end shifters

[Andrew Karre]

I have an old set of Shimano friction barcons. I haven't installed them and I'm cusrious about their
operation. I am largely a post-friction/downtube cyclist, but I do have a bike I built up with Nuevo
Record friction shifting, and its operation makes sense to me. And I thought barcons worked
similarly (friction in the lever resists derailer spring, etc.). These levers don't seem to have
friction, but instead a rather strong spring. How does this work? How do they stay in a gear?

Thanks for any help, AK

[email protected]

 

[Sheldon Brown]

Andrew Karre wrote:

> I have an old set of Shimano friction barcons. I haven't installed them and I'm cusrious about
> their operation. I am largely a post-friction/downtube cyclist, but I do have a bike I built up
> with Nuevo Record friction shifting, and its operation makes sense to me. And I thought barcons
> worked similarly (friction in the lever resists derailer spring, etc.). These levers don't seem to
> have friction, but instead a rather strong spring. How does this work? How do they stay in a gear?

Pure "friction" levers have a problem, they move easier in one direction than the other.

There has to be sufficient friction to keep the derailer's return spring from snapping the lever
back when you let go of it. When you're moving the lever in the direction of the spring pull, it
moves very easily, because the spring pull almost equals the friction, and they'mostly cancel out.

Shifting the other direction, however, you're working against both the spring tension and the
lever friction.

Toward the end of the friction shiftin era, a couple of solutions to this were developed:

Some levers equipped the friction clutch with a ratchet, so that the friction was only applied in
the direction that opposed the spring. SunTour "Power Shifters" used this approach.

Shimano's answer to this problem was to put a counter-spring in the lever. This spring was designed
to cancel out the effects of the derailer's return spring, so the lever would stay put with only a
very small amount of friction, providing a light action in both directions.

Late-model Shimano friction shifters were the most sophisticated ever, but S.I.S. made all that
stuff obsolete.

Sheldon "Indexed" Brown +----------------------------------------------------------+
| And what are all these mysteries to me, | Whose life is full of indices and surds? | x^2 +
| 7x + 53 |
| = 11/3 --Lewis Carroll |
+----------------------------------------------------------+ Harris Cyclery, West Newton,
Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts
shipped Worldwide http://captainbike.com http://sheldonbrown.com

 

[Andy M-S]

[email protected] (Andrew Karre) wrote in message
news:<[email protected]>...
> I have an old set of Shimano friction barcons. I haven't installed them and I'm cusrious about
> their operation. I am largely a post-friction/downtube cyclist, but I do have a bike I built up
> with Nuevo Record friction shifting, and its operation makes sense to me. And I thought barcons
> worked similarly (friction in the lever resists derailer spring, etc.). These levers don't seem to
> have friction, but instead a rather strong spring. How does this work? How do they stay in a gear?
>
> Thanks for any help, AK
>
> [email protected]

I recently picked up a pair of these as well...they have this fairly strong spring that seems
designed for centering the levers. Look like they're from the era of Suntour barcons, but not nearly
as nicely finished.

If anyone has info one these, I'd appreciate it.

 

[A Muzi]

"Andrew Karre" <[email protected]> wrote in message
news:[email protected]...
> I have an old set of Shimano friction barcons. I haven't installed them and I'm cusrious about
> their operation. I am largely a post-friction/downtube cyclist, but I do have a bike I built up
> with Nuevo Record friction shifting, and its operation makes sense to me. And I thought barcons
> worked similarly (friction in the lever resists derailer spring, etc.). These levers don't seem to
> have friction, but instead a rather strong spring. How does this work? How do they stay in a gear?

That system, along with Suntour's Power Shift, Simplex (also GPM) Retrofriction, other Shimano
downtube models with left-side spring and Campagnolo's short-lived retrofriction lever all balance
the changer's return spring against either a spring or a one-way motion in the lever so as to
acheive a "neutral" feel when shifting both up and down. Shimano's bar-con with spring does this as
well as any. Quite a nice shifter IMHO.

Do note that you'll need to overtighten the adjustment to lock the lever's position while setting up
the cable. Note also that the mounting cone/wedges in the handlebar needs lubrication and installs
with an anti-clockwise turn of the wrench.
--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971