NSU Max

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NSU Max Standard
NSU Max 1955
NSU Max Spezial, built in 1956, at the Moselschiefer Classic in Mayen
NSU Spezialmax with sidecar, rear suspension struts retrofitted (Supermax had a different air suction rubber: white and funnel-shaped, see picture below)
NSU Supermax

The NSU Max was one of the most popular 250cc motorcycles of the 1950s and 1960s. The official type designation was: NSU 251 OSB . The abbreviation OSB was the abbreviation for O bencontrolled; S port; B lockmotor. The number 251 gave information about the displacement and the number of cylinders ( 251 = 25 0 cm³; 1 cylinder). It was manufactured from 1952 to 1963 by the NSU engine works in Neckarsulm. 97,120 units were built.

Standard versions

There were three versions during production:

  • 1952–1954 Max Standard (half-hub brakes, small tank)
  • 1954–1956 Max Spezial (full-hub brakes, large buffalo tank )
  • 1956–1963 Supermax ( rear struts , paper oil filter, 18 hp)

The Standardmax was only named after the publication of the Spezialmax in 1954. Before that, the designation was simply Max. In order to avoid the high import duty for 250 cm³ motorcycles in Austria , the 301 OSB version with 297 cm³ displacement was built in 1955/56 especially for export to Austria (2756 pieces). It developed 15.4 kW (21 hp) at 6600 rpm.

This version was not officially sold in Germany. The sales prospects would also have been slim, because the advantage of the higher engine power was offset by the disadvantages of a higher vehicle tax and, above all, the fact that the 300 Max could no longer be driven with the class 4 driving license, which was widespread at the time. This was limited to vehicles up to 250 cm³.

Completely new at the NSU Max was the so-called Ultramax control of the single-cylinder engine, which means that the overhead camshaft was driven by an intermediate shaft running at half the crankshaft speed by two push rods and not by a chain or a vertical shaft. This design by chief designer Albert Roder was later retained in the Superfox, the Maxi and the two-cylinder engine of the NSU Prinz small car .

The pressed steel frame and the wheel suspension on the pushed short swing arm at the front and a cantilever swing arm with an approximately horizontal central spring and integrated shock absorber at the rear largely corresponded to the NSU Lux , but in a reinforced design.

In 1956, instead of the central spring, the Supermax received two conventional struts at the rear, as well as a modified intake system, an improved throttle grip and fine engine oil filtering. Suspension strut conversion kits were offered in the accessories trade.

With 17  HP or 12.5  kW (initially 15 HP), the NSU Max was the superior motorcycle in its class.

Technical specifications

model NSU Max (from 1954) NSU Supermax (1956–1963)
engine 1-cylinder four-stroke
Displacement 247 cc
Bore × stroke 69 mm × 66 mm
power 12.5 kW (17 hp) at 6500 rpm 13.2 kW (18 PS) at 7000 rpm
transmission 4-speed
Front suspension Short arm swing arm
Rear suspension Cantilever with central spring Swing arm with struts
Weight 165 kg 174 kg
Top speed 126 km / h
Base price 1,990 DM 2,076 DM (from 1961)

The extra power of the Supermax is based solely on a modified air filter, a modified intake space in the frame and a modified carburetor nozzle assembly.

NSU Rennmax "Delphin", 1953
NSU Rennmax "Blauwal", 1954
NSU Sportmax, 1955

Sport and racing versions

With racing and sports machines derived from NSU Max, NSU was very successful both in road racing and off-road.

From 1952 to 1954 NSU built the Rennmax, a two-cylinder racing machine, the frame and suspension of which from 1953 resembled the Seriemax and replaced the double tubular frame of the first version. However, the engine had nothing in common with the production model. It was a parallel two-cylinder with two overhead camshafts , which were initially driven by two vertical shafts , and in 1954 by just one. The 1954 engine (249 cm³) developed 39 hp at 11,500 rpm. The 121 kg heavy machine had a six-speed gearbox and reached a top speed of 190 to 195 km / h.

1953 and 1954 was Werner Haas on NSU Rennmax World Champion of 250cc. In 1954 the Rennmax won all races in which it started.

In 1955, NSU significantly reduced its involvement in road racing. Instead of the highly developed Rennmax factory racing machine, the relatively near-series Sportmax was built. The exterior of the engine corresponded to the normal Max engine and developed 28 hp (21 kW) at 9000 rpm with an open exhaust. The Sportmax was built in small series (36 pieces) and could be acquired by established private racing drivers for 4,000 DM. Although the Sportmax had significantly less power than the Rennmax a season earlier, H. P. Müller became world champion in 1955, but only after the world championship leader Bill Lomas was disqualified on Moto Guzzi . Lomas had refueled with the engine running at the Dutch TT in Assen . Hans Baltisberger won the title of German Road Champion on NSU Sportmax .

In addition to the Sportmax road racing machine, NSU developed a “Geländemax” in 1955 on the basis of the production model, which differed from this one in that it had increased engine power to 19.5 hp, a raised exhaust pipe, an underguard for the engine housing, larger shock absorbers and large tires. It was driven both solo and with a sidecar. In addition to other successes, nine NSU Geländemax drivers finished the 31st International Six-Day Race in Garmisch-Partenkirchen in 1956 with a gold medal. In addition, there were two golden factory prizes for both NSU works teams that got through without penalty points.

Erwin Schmider won ten times (1958-1967) the German off-road championship in the class up to 350 cm³ at the NSU Geländemax.

References

See also

literature

  • Dieter Herz, Karl Reese: The NSU racing history 1904–1956, Motorbuch Verlag, Stuttgart 1982, ISBN 3-87943-797-1 .
  • Peter Schneider: NSU 1873–1984: From the high-bike to the automobile, history, types and models Motorbuch Verlag, Stuttgart 1988, ISBN 3-613-01086-0 .
  • Ernst Leverkus : NSU-Max - handled correctly: Instructions for maintaining an interesting motorcycle engine. A breviary about driving a real motorcycle Motor-Presse-Verlag, Stuttgart 1959 - 2nd edition (reprint edition), Motorbuch Verlag, Stuttgart 1986, ISBN 3-613-01109-3 .
  • Klaus Arth, Stephan Thum: NSU motorcycles 1945–1964 / Better driving on NSU, Verlag Johann Kleine Vennekate, Lemgo 2001, ISBN 3-935517-00-9 .

Web links

Commons : NSU Max  - collection of images, videos and audio files

Individual evidence

  1. ↑ KFT 2/1957, p. 65