Pro Foam Tyres for the Micro RS4. Pro Foam tyres are significantly lighter than the stock rubber tyres, which helps deliver quicker acceleration for faster lap times. They're available in a variety of long-life foam rubber compounds so drivers can maximize performance according to track conditions. These tyres are pre-glued and precision trued, ready for high performance out of the box. And, they're mounted on lightweight dish wheels that will instantly give your Micro racing style looks and improved performance.