Late 1960s Schwinn Racer Question...

Quoted message said:

Hi,

First off, thanks to everyone who responded to my previous
2 posts on my Puch Prima. You were all a great help.

Latest question; I bought a Schwinn Racer from a garage
sale and the owner told me it was about 35 years old. It
appears to be a 3 speed with "indexed" shifting, but it's
done without derailleurs. Instead, a cable connects the
shift activator directly to the rear wheel to (presumably)
activate an interior mechanism. I have the following
questions:

1) How do I disconnect this from the wheel? I need to
replace the rear tire and I can't because the cable is
in the way.

2) How does this shifting mechanism work? It looks really
interesting, especially since all the previous shifters
I have seen were derailleurs.

3) Are there any sites where I can find more information
on this bike?

Thanks in advance.

You are an owner of a 3-speed internally geared hub. It uses
a planetary, or epicyclic, gear system to get the trio of
ratios. These things are very common; many thousands of
examples are in daily use worldwide.

The shifting cable is attached to a small chain which enters
the center of the axle. It can be unscrewed from its
attachment inside the hub, or alternatively there may be a
detachable connection between the actuating chain and the
shift cable.

Internally geared hubs have some advantages over derailer
gears. You can shift at a standstill, the works are
protected from the weather, and a chainguard can be fitted,
which will dramatically increase chain life. However in any
gear except direct drive, there are mechanical losses which
are somewhat greater than a clean and lubricated derailler
system. Geared hubs are currently available in 2, 3, 5, 7,
8, and 14 speeds.

To learn more, visit rohloffusa.comframe.htmOpen ↗ or
sheldonbrown.comsturmey archer.htmlOpen ↗

Sheldon's pages have a tremendous amount of info, and will
help you identify your hub and service it.

--
Ted Bennett Portland OR

may have said:

Latest question; I bought a Schwinn Racer from a garage
sale and the owner told me it was about 35 years old. It
appears to be a 3 speed with "indexed" shifting, but it's
done without derailleurs.

Yup. Almost certainly a Sturmey-Archer internally geared
hub. It probably has a little flip-top oil port on it,
between the rows of ports. Give it a small squirt of motor
oil in there once in a while.

Quoted message said:

Instead, a cable connects the shift activator directly to
the rear wheel to (presumably) activate an interior
mechanism. I have the following questions:

1) How do I disconnect this from the wheel? I need to
replace the rear tire and I can't because the cable is
in the way.

Where the cable connects to the short piece of chain coming
out of the hub end, there's a knurled jamring and a knurled
cable end; the cable unscrews from the chain there. Loosen
the jamring by backing it off a half turn or so, and you can
unscrew the cable end off of the chain assembly. The jamring
keeps the adjustment from getting out of whack; when
reassembling, adjust for proper shifting as detailed in the
instructions on Sheldon Brown's website, and make sure that
the jamring is tightened back up against the cable end to
lock it in place.

Quoted message said:

2) How does this shifting mechanism work? It looks really
interesting, especially since all the previous shifters
I have seen were derailleurs.

It uses a planetary gear system inside the hub; the cable's
motion shifts bits inside to determine which part of the
assembly is engaged with what. Automotive automatic
transmissions use the same kind of gear assemblies.

--
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