It was described in the book ‘Fahrrad und Radfahrer’ (Wilhelm Wolf, 1890). Click here for the original German text.
Characteristic are the handlebars, which are pointing firmly in the backward direction, the bigger space between tyre and backbone and a front fork with more rake. The book describes: ‘At the 50 inch Wachtlers Special-Rational with 20 inch rear wheel, front fork and grips are 2,75 inch to the rear. The free space between front tyre and fork and backbone is ca. 17 mm, so nothing gets stuck between them. The adjustable cranks are at least 6 inch. Thanks to the bigger space (between tyre and backbone) this Rational could be chosen an inch smaller if used as a tourer.’ He continues with the safety aspect: if you fall, you don’t fall so high if you have a smaller wheel...
I continue translating the last part: ‘During last winter (that was: 1889-1890) a lively discussion in the English sports papers turned out against the low bicycle (they mean: the rear wheel driven safety) and in special favour of the Rational bicycle and the geared Facile’.
It must have been the last attempt to
keep the ordinary alive.
As we can see on the page in the Seidel
& Naumann catalogue of 1890 this model was also part of the
S&N-line, yet with normal handlebars (at least on this drawing).
The Wachtler we see in the pictures has indeed 50/20 inch wheels. The saddle support has engraved: 'Naumanns Dresden Special Club'. It has serial number 777 left of the neck and number 713 on top of the handlebars. I have no explanation for the difference, parts seem to fit well. Maybe an early accident and factory replacement? Both numbers are far too low to be S&N numbers, so we assume the Wachtlers had their own range of serial numbers.
Enjoy the details, like the Lucas hub lamp. A lot of parts, like hubs and head are easy to recognise on the other Seidel & Naumann bikes I show pictures of on this website.
Thanks to Max for pictures and all the information.
 |  |  |
| |  |  |
 |  |  |
 |  |  |