by Mike Hanson
Also known as the "Tiny Tire" Shadow, the AVS (Advanced Vehicle Systems) Shadow Mk. 1 was designed by Trevor Harris. Working in concert with Firestone, special tires were developed that were 30-35% smaller in diameter than what was typical for the era (the rims on the front were 10", and were 12" in the rear). The goal was to minimize frontal area as much as possible - the front end was 14 inches lower than the competing McLaren!
Unfortunately the small wheels resulted in a domino effect - the brakes were much smaller as well, at 8 inches in the front, which resulted in cooling problems. Magnesium centrifugal fans (swiped from a Corvair engine) were mounted to the outside of the front rims in an effort to cool them down. Rear brakes were mounted inboard. The small frontal area also impacted the suspension, which was a unique parallelogram design.
The ultra-low, almost cart-like car also had trouble keeping the engine cool. The radiators were mounted inside the large rear wing, and the two "trumpet" scoops on the roll bar also aided in ducting air to the radiators. Even with all that, the car continued to experience cooling problems.
While a valiant effort, the Mk 1 never did well at the races. The small tires and tight suspension should have worked in theory but in the real world of rough track surfaces it was a difficult car to control. Ultimately, the Shadow Mk 1 was replaced by a much more conventional car, and eventually Shadow became the Can-Am champion in 1974.
That championship car was the Shadow DN4. The bodywork on the all-black car was distinctive, but the design was fairly conventional as Can-Am cars go, with a mid-engined 8.8 litre Chevy V8 putting out 850 bhp. The 1974 season was cut short because interest in the Can-Am was waning, but there was a champion - and after the race had been dominated through the years by the Kiwis (McLaren) and the Germans (Porsche), it was nice that the last champion of the original Can-Am series was an All-American team (though the last race was won by McLaren).