In 1972, the FIA merged the B5 and B6 categories into the B5 class for vehicles with a maximum engine capacity of 3,000 cc. In the Czechoslovak championship, the displacement limit was changed to 2,000 cc, whereupon the then state-owned company AZNP (Automobilové závody, národní podnik; today the Škoda brand) began preparing an open two-seater for circuit and hill climb racing.
With the exception of the striking aluminum body, in which the front and rear could be folded up, the designers mainly used the modified parts of the Škoda 110 L production model for the construction of the Škoda Spider B5. The four-cylinder engine with OHC valve control was a prototype from the Škoda 720 and produced 150 hp. In the basic version, it was intended for the new Škoda models of classic design. In the Spider B5, the engine was located in front of the rear axle.
The racing car, of which only one was produced, was very compact with a length of 3,650 millimetres, a width of 1,700 millimetres and a height of 850 millimetres. The body and engine were continuously optimized. The displacement of the engine from the Š 720 OHC series increased from the original 1.5 to 1.6 to 1.8 liters. In the final season in 1975, an engine with a displacement of 2.0 liters was also used, which enabled a top speed of up to 220 km/h depending on the overall gear ratio.
Initially, the designers tested the five-speed racing gearbox from the Tatra 603 in the racing car, but soon replaced it with a Škoda gearbox developed in-house. The steering was the same as the standard version, only the steering column was adapted. The necessary deceleration was provided by modified standard brakes (disc brakes at the front only). The double wishbone suspension at the front and the swing axle at the rear were based on the corresponding standard components from the Škoda 110; coil springs and shock absorbers were designed for the vehicle weight of just 630 kilograms. Dunlop racing tires were fitted to the 13-inch alloy wheels.
The Spider B5's unpredictable handling earned it the nickname 'Skokan', which translates as 'jumper'. Regular driver Jaroslav Bobek came from a famous motorsport family: his older brother Václav had been successfully racing Škoda cars since the late 1940s and his son Václav Bobek Jr. competed in Czechoslovakian hill climb races in 1975 and 1976 in the Spider B5, which subsequently found its way into the factory museum. Jaroslav Bobek switched to the more modern Spider II Type 733 with a two-liter engine during this period after numerous victories on circuits and in hill climbs at home and abroad and two championship titles (1972 and 1974).
The Škoda Spider II was launched in the middle of the 1975 season. As it was originally built in accordance with the technical regulations for vehicles up to 2,000 cc in the European Sports Car Championship, it was necessary to further develop the bodywork. To this end, the expertise of aerodynamics experts from aircraft manufacturer Aero was called upon. Unlike its predecessor, the Spider B5, whose floor platform originated from the series and was modified accordingly, the front section of the Spider II was based on a self-supporting skeleton. It was spot-welded from thin sheet steel and the adjoining lattice structure carried the powerful engine.
The Škoda aluminum engine from the 720 series was available with OHC or DOHC valve timing, dry sump lubrication and produced up to 180 hp. The FT200 gearbox, Girling brakes and Koni shock absorbers were imported. The suspension of the 13-inch wheels with double wishbones at the front and multi-link suspension at the rear corresponded to the state of the art of European racing cars at the time, and the tires came from Goodyear. With an unladen weight of 585 kilograms, the Spider II reached a top speed of 200 to 240 km/h, depending on the gear ratio, and accelerated from 0 to 100 km/h in just four seconds.
Jaroslav Bobek took part in several races with this prototype during the 1975 season - including the famous Ecce Homo hill climb in Šternberk, not far from the city of Olomouc. There he was the first ever starter to achieve a time of under four minutes. The Spider II was also at the front of the field in other races and drove to several victories. The career of the fastest Škoda car to date ended with a curious accident at the hill climb in Hlásná Třebáň. The victorious Jaroslav Bobek drove through the finish line and collided with another car that was reversing in the finish area for unknown reasons. The drivers were unharmed, but the self-supporting skeleton of the vehicle was so badly damaged that it was decided not to repair it at the time.
Today, the Škoda Spider B5 is one of the Škoda Museum's most valuable exhibits, while the Škoda Spider II is currently being extensively restored.