Schwinn bicycles began using slimline tanks in 1962.
There were several different versions of the slimline tank as far as paint and decals go, but all used the same exact frame (there are two frame versions actually – one for men and one for women).
These tanks are well documented in the original dealer and consumer catalogs provided by Schwinn.
Mens Tanks:
In 1962 there were two bikes that had a slimline tank included.
The American featured a slimline tank that had a chrome top and solid color bottom and included a horn and unique decals.
The Fleet however, had a different paint job and did not include a horn, therefore there was no horn button hole on the tank. The top portion of tank was painted (not chrome) white, and the bottom portion was painted a solid color that matched the bikes’ color. See the middle tank in picture or the top picture of this page to see this type of tank.
In 1963 there were three models with slimline tanks.
The Jaguar and the American now had the slimline tank with the chrome top and the solid color bottom, and the American tank lost its unique decals.
On the Fleet models there was also a change in it’s tank configuration. Now the “schwinn” was on the bottom portion of the tank, rather than the top.
From 1963 on the slimline tanks stayed the same.
In total there are only four different slimline tank designs:
The rarest slimline tank is the 1962 Schwinn Fleet no horn configuration with the “Schwinn” on top. It was only made for one year.
1962 Fleet original configuration (no horn, no chrome, “schwinn” on top)…

1962 American original configuration (horn, chrome, unique decal)…

1963 Jaguar Mark V and American and future Panthers (horn, chrome, no unique decal, “schwinn” on bottom…

1963 Fleet second configuration (no horn, no chrome, “schwinn” on bottom)…

Here is a tank taken apart showing the pieces. Notice there are…
Note: Not all slim line tanks came with horns. Early Fleet models did not have horns.
This means that not every slimline tank will have a horn hole. The example pictures taken here are of a slimline tank with no details (paint or decals).
The frame consist of two pieces – the left side and the right side.
The exteriors of these pieces are shown above, to the left are the interiors of the pieces.
There are frame mounts on the interior on one side is a small stabilizing tab and on the other are “U” shaped mounts which have the screw holes in them so that the tank is mountable.
The exteriors were decorated different for different years and models.
Some slimline tanks have a hole for the the horn button, some do not.
A good tank is one that has a solid shape without major dings or dents.
The horn unit basically consists of…
The horn uses a “D” cell battery.
It makes an awkward noise in my opinion, but horns that work are an enviable detail for a restored bike to have.
The screws are Phillips. the two that mount the frame are about an inch long.
The screws that mount the horn to the frame are very short.
I have made a video that shows how to take a tank apart and also features a working horn so you can hear what it sounds like.