Two things you pray for when testing a Radical: a dry track and a circuit full of fast curves where its downforce can really be exploited. Spirits were high as I rolled into the Bedford Autodrome under blue skies, then promptly sank when I saw that we could only use a small ribbon of track. You see the new SR4, which replaces the original Clubsport, is just like every other Radical. Here, it wouldn’t get out of third gear and the 1200cc Kawasaki engine – as used in the ZZR 1200 bike, but tweaked to 190bhp at 11,000rpm – wouldn’t have sufficient torque to lunge even the 450kg SR4 out of the tight stuff.
Wrong. Anyone serious about track days – serious as in ‘I’ve mastered the GT3 and want to move up a level’ – needs to sample one of these. Based on an entirely new tubular chassis, with a totally revised aero kit incorporating front-mounted air intakes for the first time on a Radical, it is superb.
Remember that ecstatic feeling when you drove a go-kart for the first time? That’s what the SR4 offers. Something so far removed from any other road car (Caterham included) that it responds just like a race car. Accuracy takes on new levels of calibration: missing an apex by 5cm in the SR4 feels clumsier than not getting round a corner at all in a Porsche Cayenne. In fact, this was a race car, but the difference between it and a car you can drive to the circuit is about £2500 in legal bits.
What a shame that you won’t be able to get there on the Slovakian Matador slicks. Designed specially for the SR4, they provide an uncanny balance of superb grip and easily managed breakaway characteristics. So where I’d expected the SR4 to bog down the whole time, it lugged really hard low down. And despite running slicks, it could be drifted about at will. Radical has commissioned the same company to create a road-legal track tyre and, if this first effort is anything to go by, it should be an absolute stunner.
Mechanically the SR4 is grass-roots Radical: bike engine, chain drive, Quaife LSD and double wishbones all round. There’s even a proper reverse gear. It’s a car sorted on the track and then released onto the road. As a result I’ve almost given up being impressed by what these cars can do on a circuit. This SR4, like the SR3, is so much faster and better than any other conventional machine on sale that nothing can touch it. And having driven the SR3 on the road during that idiotic story recently (Wild Bunch, 10 February), I can honestly say that a road-spec SR4 would be no more inconvenient than any other stripped-out quasi-racer without a screen.