Prior to the release of the "Carrera" chassis, Russkit was producing the "Spyder" and "SuperSpyder" inline brass chassis'......these were rather flimsly at best, and were nowhere near the performance of the "Carrera" sidewinder cars. A fair bit of work was needed in chassis stiffening to get these "Spyders" to perform. The "spyders" were mainly found under Russkits' hard body Cooper and Ferrari 156.
Cheers
Chris Walker
Following is one of their hard body Coopers..............a lot of chassis work to prepare it for vintage racing

And a "carrera" chassied McLaren............also a fair bit of work done for vintage racing

