Pitty 
On a scooter, a pressed-steel full enclosure under the seat encases the rear wheel, engine and gearbox. In order to remain within its operating temperature range, a cooling fan was added to the air-cooled MZ engine. Powering this fan sapped the engine’s already inadequate 5 bhp power output. IWL copied Glas and Heinkel by giving the Pitty a large fairing that enveloped the front wheel. This increased the scooter’s weight to 139 kilograms (306 lb), which was heavy for its class and further impeded its under-powered performance. IWL claimed a 70 km/h (43 mph) top speed, but in practice this was seldom achieved.
At the beginning of 1955, reporters from the East German Der deutsche Straßenverkehr magazine tested the Pitty and gave IWL numerous suggestions to improve it. Numerous customers who bought the scooter also complained. The Pitty has a dualseat that riders complained was too hard. Unlike most scooters, the Pitty has no steering lock for security. Its only anti-theft device is a flap in the enclosure under the seat that can be closed over the fuel tap and locked. IWL reacted to criticism by quickly developing a successor model, and kept the Pitty in production for only just over a year. In this time a total of only 11,293 Pitty scooters IWL’s first production model, named the Pitty, was launched early in 1955 at a retail price of 2,300 Marks. The Pitty’s front wheel had leading link suspension, while its rear wheel had hydraulically damped swingarm suspension on which the engine and gearbox unit was mounted: an arrangement that Vespa had pioneered. However, IWL followed West German practice in mounting the engine in front of the rear wheel instead of beside it, thus giving the Pitty a much longer wheelbase than its Italian counterparts.
IWL’s first production model, named the Pitty, was launched early in 1955 at a retail price of 2,300 Marks. The Pitty’s front wheel had leading link suspension, while its rear wheel had hydraulically damped swingarm suspension on which the engine and gearbox unit was mounted: an arrangement that Vespa had pioneered. However, IWL followed West German practice in mounting the engine in front of the rear wheel instead of beside it, thus giving the Pitty a much longer wheelbase than its Italian counterparts.
SR 56 Wiesel 
In 1956 IWL replaced the Pitty with the SR 56 Wiesel. "SR" stands for StadtRoller ("town scooter"), 56 is the year, and Wiesel is German for weasel. Instead of the Pitty’s huge fairing, the Wiesel has a more conventional scooter fairing behind the front wheel and a separate front mudguard. This reduced the weight to 124 kg (273 lb): still heavy, but 15 kg (33 lb) lighter than the Pitty.
Also in 1956 MZ introduced the RT 125/2 motorcycle, for which it marginally increased engine power to 6 bhp. Both the weight reduction and the power increase were small, and the Wiesel’s power-to-weight ratio was inferior to that of numerous western competitors. IWL claimed a 60 km/h (37 mph) cruising speed, but in reality the Wiesel was only 3 km/h (2 mph) or 4 km/h (2.5 mph) faster than the Pitty.
Despite customer complaints, the Wiesel retained its predecessor’s hard upholstery, lockable fuel tap flap and lack of a steering lock. It was easy for a thief to force the flap, and Der deutsche Straßenverkehr’s testers were astonished that IWL had not rectified this fault from the previous model. IWL produced the Wiesel until 1959, by which time a total of 57,400 had been built.
SR 59 Berlin 
In 1959 IWL replaced the SR 56 Wiesel with the SR 59 Berlin. This shared the same bodywork as the Wiesel but had well-upholstered separate saddles for the rider and pillion passenger. Also in 1959, MZ introduced the RT 125/3 motorcycle, which had not only a slightly more powerful engine but also a four-speed transmission. IWL specially requested that the version of the RT 125/3 motor made for the scooter be bored out to 143 cc, which increased power output to 7.5 bhp. IWL credibly claimed a top speed of 82 km/h (51 mph) and a cruising speed of 70 km/h (43 mph). The four-speed transmission improved the machine’s flexibility, making hill-climbing significantly less strenuous. The Berlin at last gave riders in the DDR a scooter that was good enough for practical use. It was therefore just as well that IWL at last included a steering lock to secure the relatively desirable Berlin against theft.
The Berlin still had less power than many of its western counterparts. In common with its predecessors, its front suspension was undamped, which on roads as bumpy as the DDR’s was a significant weak point. Nevertheless, the Berlin secured IWL’s first export orders. IWL produced the Berlin until the end of 1962, by which time a total of 113,943 had been built.
TR 150 Troll
In 1963 IWL replaced the SR 59 Berlin with the TR 150 Troll 1. Whereas the Wiesel and Berlin had retailed for 2,300 Marks, the same price as a Pitty in 1954, for the Troll 1 the price was increased to 2,550 Marks.
"TR" stands for TourenRoller and "Troll" stands for TourenRoller Ludwigsfelde ("Ludwigsfelde touring scooter") emphasising the longer journeys on which IWL scooters were now being ridden. The "1" at the end evidently indicated that IWL hoped to develop a further model. However, in December 1962, during the Troll 1’s development, the Ministerrat der DDR ("Council of Ministers of the GDR") had announced that the factory would switch to making a new model of IFA truck. This decision may have acted as a disincentive to improve the Troll 1 from before the model’s launch in 1963 until the end of production in 1965.
Both in Germany and in most of the European states to which IWL might have hoped to export scooters, trolls are known from Norse mythology and Scandinavian folklore as beings that are in many cases slow-witted, in some cases ugly, seldom friendly to humans and in a few cases inclined to kill and eat people. Why any vehicle maker would choose to name one of its models after such creatures is not clear.
In 1962 MZ had introduced the ES 150 motorcycle, and the scooter version of its 143 cc engine supplied for the Troll 1 had its power increased to 9.5 bhp. The rear chain runs in an oilbath in a patent MZ hard-rubber enclosure, which keeps oil in and dirt out and greatly prolongs chain life. IWL revised the bodywork, giving a tail unit like that of the Heinkel Tourist model A2 and quickly detachable side panels like a Dürkopp Diana. Each side panel is secured by a central bayonet lock and is simple to undo and light to remove, easing access to the engine, gearbox and rear chain.
For the Troll 1, IWL reverted to a dualseat, perhaps because twin saddles were becoming dated. The Troll 1 had 160 mm (6.3 in) diameter drum brakes: 10 mm (0.4 in) bigger than on all previous IWL models.
Tatran S 125
From 1966 a scooter from the ČSSR was imported for sale in the DDR. The Tatran S 125 had only a 124 cc engine producing 7 bhp. However, with less weight and a shorter wheelbase than any IWL model, the Tatran’s power-to-weight ratio was practical and at last offered East Germans a real "town scooter"
Campi trailer 
Although IWL projected their scooters as a"town scooters", new private motor vehicles were in such short supply in the DDR that customers made no such distinction. The Berlin was capable of longer journeys, including holidays, but a scooter has far less luggage capacity than either a small car or a motorcycle and sidecar combination. Instead of devising a sidecar to fit the Berlin, IWL collaborated with Stoye of Leipzig, the DDR’s sidecar manufacturer, to develop a lightweight, single-wheel trailer.
The result was the Campi trailer, which was styled to complement a scooter and was roomy enough to carry a set of 1960s camping equipment. IWL made the Campi’s chassis, including a tubular steel towing link that connected to the scooter behind the pillion seat and above the rear light. Stoye made the bodywork, which is aluminium and contributes to the trailer weighing only 30 kg (66 lb). This made it light enough for a Berlin’s 7.5 bhp engine to cope with the combined weight of its rider, passenger, trailer and luggage, albeit at markedly less speed than when being ridden solo.
The Campi added inconveniently to the length of the scooter, while adding less luggage capacity than a sidecar. Because of these limitations, its use was confined chiefly to holiday and leisure journeys. The Campi was made until 1965, by which time a total of about 5,700 of these trailers had been built.
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