Speed with Guy Martin: Gravity Racer

Speed junkie Guy Martin takes on new speed-based challenges in the second series of Speed with Guy Martin. In the final programme in the series, Guy takes on the challenge of building the fastest soapbox racer the world has ever seen, in an attempt to set a new speed record using just the pull of gravity and a tarmac road. To get to grips with blisteringly fast speeds on a public road, Guy tries his hand at street luge with ex-world champion Helene Schmit, before meeting up with his team of engineers to explore the science of rolling resistance and the importance of tyre pressure. Armed with what they believe to be the perfect formula, Guy's team produce a completely unique soapbox cart and, after training with the Team GB women's bobsled pair, are hoping for the perfect push start. Confidence is high and the adrenaline is flowing. The record attempt gets off to a flying start but are disaster and mayhem just around the corner?