RT 125

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RT 125
DKW RT 125 W (1950)
Manufacturer: DKW ( Auto Union ), IFA , MZ
Production period: 1939-1965
Engine: Single cylinder - two-stroke engine
Displacement: 123 cc
kW (PS): 3–5 kW (4.75–6.5 hp)
Transmission: 3- and 4-speed
Exhaust gas cleaning: no
Top speed: 75-90 km / h
Previous model: DKW RT 100
Successor: MZ ES 125/150
Similar models: NSU Fox

RT 125 ("Reich type", rounded displacement 125 cm³ ) is the name of a motorcycle with a single - cylinder two-stroke engine , which was manufactured by other manufacturers under the DKW brand of Auto Union from 1939 and after the Second World War until 1965. The RT 125, designed by Hermann Weber at the DKW parent plant in Zschopau , is the most copied motorcycle in the world.

With around 450,000 units, it is considered the most popular motorcycle in Germany.

technology

All RT 125 have an air-cooled two-stroke engine with Schnürle - reverse circulation and flat shank . The bore of 52 mm and the stroke of 58 mm result in a displacement of 123  cm³ . Depending on the model, the engine has an output of 4.75 to 6.5 hp.

The engine block and cylinder head are made of an aluminum alloy; the cylinder is made of gray cast iron . The engine, which is mounted in a closed monotube frame, has a voltage-regulated 6 V alternator and a carburetor with float and needle valve . One roller chain each is used for the primary drive from the crankshaft to the gearbox and the secondary drive to the rear wheel. The gearbox with countershaft is operated by a footshift lever using a claw and a special segment and has three or four gears depending on the version; Between the engine and the gearbox there is a multi-plate clutch that can be operated from the left handlebar handle with a Bowden cable .

The engine is lubricated as a mixture lubrication with a mixing ratio of the two-stroke mixture of 1:25 to 1:40 (oil / petrol). The top speed of the RT 125 was 75 to 90 km / h, depending on the model.

Pre-war model

DKW RT 3 PS from 1939, except for the speedometer and rearview mirror required by the TÜV in original condition
DKW RT 125 from 1940, construction period 1940–1941

From the late 1920s, the DKW brand , which had been part of Auto Union since 1932, was the world's largest motorcycle manufacturer. The RT 125 was based on the RT 100 , which came on the market in 1934 and was also known as the RT 2½ HP. In the 100 cm³ class, the machine was a sensation at the time because it had a kick starter , three manual gears, footrests and did not need the pedals that were common in this class at the time , so it was a "real" motorcycle and only cost 345 Reichsmarks .

In the course of a model upgrade in 1936 the RT 2 ½ PS was further developed with a slightly more powerful engine to the RT 3 PS. The price remained unchanged.

Main article: DKW RT 100

The RT 125 was presented by DKW in 1939 as the last civilian development before the Second World War . The most important innovation in the newly created 125 cm³ class was above all the completely redeveloped engine. It has a DC alternator with battery ignition and develops 4.75 hp, which is sufficient for a top speed of 80 km / h. The three-speed foot switch was also new. The motorcycle consumed an average of 2.5 l / 100 km and cost 425 Reichsmarks - at the time the gross monthly salary of an elementary school teacher; Passenger seat and speedometer were also available. The RT 125 was only available in black; empty it weighed around 70 kilograms.

Back then, the motorcycle was superior to many competing models in terms of performance, but it was cheaper. The NSU 125 ZDB , presented in 1941 - with a 122 cm³ engine, 4 hp and a top speed of 70 km / h - cost 35 Reichsmarks more than the RT 125.

After the Second World War, this machine was the basis for the new beginning both in the old DKW parent plant in Zschopau ( Saxony ) and in the newly founded Auto Union in Ingolstadt ( Bavaria ). It was also a reliable “people's motorcycle” that many could afford. It was just as economical as a 100 cm³ light motorcycle and almost achieved the performance of a 200 cm³ machine.

Model overview
DKW RT 100  (2½ HP) DKW RT 100  (3 HP) DKW RT 125 DKW RT 125-1
construction time 1934-1936 1936-1940 1939-1941 1943-1944
number of pieces 10,000 61,850 21,000 12,000
power 2.5 hp 3 hp 4.75 hp 4.75 hp
Top speed 60 km / h 65 km / h 80 km / h 80 km / h

Wehrmacht model

DKW RT 125-1 of the Wehrmacht , years of construction 1943–1944

In 1941, production of the RT 125 was stopped in order to be able to supply the Wehrmacht with larger numbers of the NZ 350-1 model . When those responsible noticed that the NZ 350-1, with its unladen weight of 175 kilograms, was often too heavy and unwieldy for soldiers, it was decided to use a lighter motorcycle for frontline use.

As a result, production of the RT 125 was resumed in 1943 with slight modifications for military use under the name RT 125 newer version (RT 125 n.A.). The changes to the Wehrmacht motorcycle, also known as the RT 125-1, include a larger tank with a military tank lid (measuring cup), frame reinforcement struts (such as the NZ 350-1), a vortex air filter, in principle similar to the NZ 350-1, an engine made entirely of gray cast iron , Speedometer drive with ISGUS speedometer, coil suspension of the trapezoidal fork (instead of rubber band suspension as in the civilian model), panniers and the paint in the military paint scheme introduced from 1943 in the standard color 43 (dark yellow) or olive green. According to the production plan, 600 machines were to leave the factory buildings every month in 1945.

With a curb weight of 91 kilograms and a permissible total weight of up to 240 kilograms, the motorcycle was light and agile. Around 12,000 vehicles had been delivered to the Wehrmacht by the end of the war. In 1944, the Army High Command released 100 RT 125s each for export to Switzerland and Sweden. By the end of March 1945, 165 of the guaranteed 200 motorcycles had been delivered.

The RT 125 n.A. and the DKW NZ 350-1 are the only motorcycles that were still built for the Wehrmacht towards the end of the war.

IFA and MZ models in the GDR

The IFA / MZ RT 125 series motorcycles rolled off the assembly line at VEB Motorradwerke Zschopau between 1950 and 1965. The basis was the pre-war machine RT 125. During the construction period, the machine was renamed several times, most recently it was called MZ 125 .

The RT 125 in the Federal Republic of Germany

DKW RT 125 (1953) Data
engine 1-cylinder two-stroke with flat pistons
Displacement 123 cc
Bore × stroke 52 × 58 mm
compression 1: 6.1
Power at 1 / min 4.2 kW (5.7 hp) for the 4800
Carburetor Bing 1/20/20
cooling Air cooling (airflow)
transmission 3-speed gearbox with foot switch
coupling Multi-disc clutch in an oil bath
frame Closed tubular steel frame
Brakes Inner shoe brakes front and rear, Ø 140 mm
Front suspension Telescopic fork , hydraulically damped
Rear suspension No
wheelbase 1268 mm
overall length 1950 mm
Overall width 660 mm
Handlebar height 880 mm
Saddle height 660 mm
Ground clearance 125 mm
wheel size 2.75 x 19
own weight 83 kg
Perm. total weight 236 kg
Tank capacity 9.5 liters
Standard consumption 2.3 l / 100 km (mixture)
Top speed 82 km / h
DKW RT 125 in the museum mobile of Audi in Ingolstadt ; Year of manufacture 1950
DKW RT 125/2, manufactured in 1952
DKW RT 125/2 H, manufactured in 1956, unrestored
An RT 125 of the motorcycle racing driver Eugenio Beltrami (right), 1950

At Auto Union , which was newly founded in Ingolstadt , production of the DKW RT 125 W, which was only slightly modified compared to the pre-war model, began in 1949. The W stood for West to clearly distinguish it from the IFA DKW RT 125. Up to the end of 1950 the models still had parallelogram forks with rubber springs, from 1951 hydraulically damped telescopic forks. The empty weight of the RT 125 increased from originally 66 kg to 84 kg (1952) and 87 kg in the last version in 1954 with rear suspension.

From 1951 until production was discontinued in 1957, the RT 125 was the most popular and best-selling machine in its class - in 1952 almost every second registered eight-liter machine was an RT 125. One of the reasons for this was its economic efficiency: low taxes (24 DM / year) and low consumption of 2.3 l / 100 km and the purchase price of around 980 DM at that time, to which, however, a separately reported "inflation surcharge" of 65 DM was added from autumn 1951 - this is how the first wave of price increases after the currency reform was handled.

In 1951 a journalist from Stuttgart drove to the Zugspitze on the Bayerische Zugspitzbahn route with a standard RT 125 .

The RT 125/2 from 1952 received a larger carburetor, increasing the engine output to 5.7 hp, and the ignition lock was relocated from the battery box to the headlight housing. Chrome-plated rims, a side chrome-plated petrol tank (previously black) and Jurisch rear wheel suspension for an extra charge of 90.00 DM were available as special equipment.

In 1954, the RT 125 / 2H received rear wheel suspension as a straight-line suspension with hydraulically damped struts and full-hub brakes. The price rose with the facelift and the RT now cost 1045 to 1225 DM, depending on the equipment. In Ingolstadt, after many further developments, production was discontinued in 1957 with the DKW RT 125/2 H.

An RT 125 manufactured under license in Italy by SpA Motauto Bologna was sold under the name DKW 125 Lusso / MS . This motorcycle is characterized by a modified design and a rear swing arm.

After major losses in the motorcycle business, DKW two-wheeler production was merged into the Zweirad Union in 1957/58 . In 1966 the naming rights were sold to the Sachs group. In the period that followed, newly developed motorcycles were sold here under the name DKW RT 125.

Model overview
DKW RT 125 W DKW RT 125/2 DKW RT 125/2 H
construction time 1949-1952 1952-1956 1954-1957
number of pieces 55,639 50,029 28,349
power 4.75 hp 5.7 hp 6.5 hp
Top speed 75 km / h 80 km / h 84 km / h
Price in DM 945-980 1045-1095 1175-1225

Copies

Both the RT 100 and the RT 125 were copied in England during the Second World War. From 1939 Royal Enfield built the RE model, also known as "The Flying Flea". The "Flying Flea" packed in wooden boxes was dropped on parachutes from aircraft for the British ground units. From 1939 WSK in Poland and Jawa in what was then Czechoslovakia also built the RT 125 as license versions.

After the Second World War, no longer protected by patents , the RT 125 became the most copied motorcycle in the world. Many well-known manufacturers sometimes copied the motorcycle down to the smallest detail.

In 1946 the Soviet comet K 125 appeared . Also the Harley-Davidson Hummer built from 1948 , also under the model designation “125 S” for “Super” or simply “Harley-Davidson 125” on the market, the British BSA Bantam , which is a mirrored copy of the engine due to different customs specifications has, the Soviet Moskva M1A or the Yamaha YA-1 (the company's first motorcycle) are copies of the RT 125. The rights to replicate in the USA, Great Britain and the USSR were reparations payments after the Second World War; the Zschopau plant was partially dismantled, and production facilities and parts were moved to the countries of the victorious powers.

Other manufacturers who copied the concept of the RT 125 included Moto Morini in Italy with the "125 Turismo" (1946–1953) and Mival and the Hungarian Csepel (1947–1954). In Poland there were three manufacturers who produced copies of the RT 125: SHL with the M02, M03 and M04 models, Sokół with the M01 125 model and WSK with the M06 model. The engine design of the SHL-M11 and WSK-M06 motorcycles is based on the engine design of the DKW motorcycle. The other parts of the motorcycles were developed by the Polish designers. The copies were also consistently developed by these manufacturers and in some cases were built into the 1970s and, as a result of a Polish-Indian cooperation, were produced in various designs from 1962 by escorts in India under the brand name Rajdoot until 2005. It was originally a license build for the Polish SHL M11 .

There were an estimated 450,000 RT 125s across Germany and more than five million worldwide.

  • Yamaha YA-1 from 1956, a copy of the RT 125

  • Polish SHL M04, built from 1948 to 1952

  • Polish Sokół 125, built from 1947 to 1950

  • Harley-Davidson Hummer, built from 1948 to 1966

  • BSA Bantam, built from 1948 to 1953

The RT 125 as a classic car

Thanks to the high production numbers, the prices for the RT 125 have only increased slightly in recent years. Vehicles in very good condition cost between 2,000 and 3,500 euros. Well-maintained pre-war and Wehrmacht models are also traded more expensive.

The acquisition of an old RT 125 is safe in view of the manageable two-stroke technology of the reliable engine and the simple chassis construction. The supply of spare parts is problem-free due to the high production figures and the compatibility of the components from the many manufacturers. Some examples are still used today as everyday vehicles.

In the Dutch Lieren an international RT-125 meeting takes place annually since 2002, since 2006 in the Saxon village of Chemnitz .

See also

Manufacturer

Competing models

literature

Books:

  • Frieder Bach, Woldemar Lange, Siegfried Rauch: DKW - MZ: Motorcycles from Zschopau and Ingolstadt. Motorbuch Verlag, Stuttgart 1992, ISBN 3-613-01395-9 .
  • Jörg Buschmann, Jörg Sprengelmeyer: DKW photo album 1921–1958. Johann Kleine Vennekate Verlag, Lemgo 2008, ISBN 978-3-935517-34-8 .
  • Jürgen Gaßebner: German motorcycle classics of the 50s. Motorbuch Verlag, Stuttgart 2001, ISBN 3-613-02177-3 .
  • Stefan Knittel, Klaus Vollmar: Schrader Motor Chronicle, DKW motorcycles 1922–1958. Motorbuch Verlag, Stuttgart 2001, ISBN 3-613-87221-8 .
  • Frank Rönicke : Schrader-Motor-Chronik exclusive, GDR motorcycles: historical documents from four decades. Schrader, Stuttgart 2000, ISBN 3-613-87203-X .
  • Halwart Schrader : Motorcycles from the GDR. 5th edition. Schrader, Stuttgart 2001, ISBN 3-613-87176-9 .
  • Andy Schwietzer: Typenkompass MZ - motorcycles since 1950. 2nd edition. Motorbuch Verlag, Stuttgart 2005, ISBN 3-613-02121-8 .
  • Andy Schwietzer: GDR motorcycle classics. Motorbuch Verlag, Stuttgart 2003, ISBN 3-613-02314-8 .
  • Jörg Sprengelmeyer: DKW motorcycles from Zschopau 1921–1945. Johann Kleine Vennekate Verlag, Lemgo 2007, ISBN 978-3-935517-31-7 .
  • Jörg Sprengelmeyer: DKW motorcycles from Ingolstadt 1949–1958. Johann Kleine Vennekate Verlag, Lemgo 2003, ISBN 3-935517-04-1 .
  • Claus Uhlmann: RT 125 - The little miracle from Zschopau - History and technology of RT motorcycles. Verlag Bergstrasse, Aue 2005
  • Manfred Woll: IFA / MZ racing history 1949–1961. Heel Verlag, Königswinter 2001, ISBN 3-89880-011-3 .

Magazines:

  • DKW RT 125 with rear suspension. In: New motor vehicle trade journal. No. 9/1949, p. 250 (new presentation of the RT 125-0)
  • The RT 125 - the powerful and economical IFA motorcycle. In: Automotive Technology . 6/1951, pp. 141-144.
  • The new IFA motorcycle RT 125-1. In: Automotive Technology. 3/1954, pp. 76-81.
  • Heike Benetti: Trapeze artist. In: Oldtimer Practice. 2/1994, pp. 55-57. (Article about the DKW RT 125 W, manufactured in 1950)
  • Christoph Heise: nimble penny fox. In: Oldtimer Practice. 12/1991, pp. 16-18. (Article about the DKW RT 100)
  • Jens Kraus: The genetic code. In: Oldtimer Practice. 4/2005, pp. 66-70. (Contribution to self-built racing motorcycles based on the IFA DKW RT 125)
  • Till Schauen: It's a family matter. In: Oldtimer Practice. 7/2004, pp. 60-63. (Article about the DKW RT 100, manufactured in 1940)
  • Andy Schwietzer: A piece of history. In: Oldtimer Practice. 2/2001, pp. 66-69. (Article about the DKW RT 125/2)
  • Klaus Ullrich: To good neighbors! In: Oldtimer Practice. 3/1995, pp. 11-13. (Article about the MZ 125/3)

Web links

Commons : DKW RT 125  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ a b c d e f Torsten Hampel: Zen or the art of maintaining a motorcycle company In: Der Tagesspiegel . December 7, 2012.
  2. ↑ a b Oldtimer Practice. 2/1994, p. 55.
  3. ↑ Corresponds to 1,820 euros in today's currency, adjusted for inflation. The figure was determined with the inflation template , has been rounded to a full 10 euros and relates to last January.
  4. ↑ Sales prospectus MB 928 (1053)
  5. ↑ a b DKW RT 125/2 Bj. 1952 (straight-line suspension with hydraulically damped struts)
  6. ↑ Advertising brochure "With DKW on the Zugspitze" ( front page ( memento of October 7, 2007 in the Internet Archive ) and inside pages ( memento of October 7, 2007 in the Internet Archive ))
  7. ↑ Picture of a DKW 125 MS ( Memento from October 7, 2007 in the Internet Archive )
  8. ^ Elective affinities - RT 125 worldwide. In: dkw-geyer.com. Retrieved July 2, 2015 .
  9. ↑ Private website on the history of the motorcycles sold under the brand name "Rajdoot" by the Indian manufacturer Escorts Limited. (No longer available online.) Archived from the original on July 1, 2015 ; Retrieved April 6, 2012 (Polish).
  10. ↑ Website of the organizers ( Memento from March 7, 2005 in the Internet Archive )
This version was added to the list of articles worth reading on August 15, 2006 .