1977 Tyrrell P34 to be auctioned.

One of the rarest F1 cars in history is up for auction.

This 1977 Tyrrell P34 six-wheeler will be offered at RM Sotheby's auction in Monaco on May 11, and is a work of art from a bygone era when small, modestly funded F1 teams could achieve great technical innovation.

Tyrrell had won several championships with Jackie Stewart in the early 1970s, but as the decade drew to a close, the team was looking for something new to stay competitive. Designer Derek Gardner's answer was a six-wheeled car with four small front wheels that dramatically reduced aerodynamic drag compared to taller wheels of conventional sizes. The effect was thought to be equivalent to extracting an additional 40 hp from the P34's Cosworth DFV engine

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Goodyear developed custom tires for the 10-inch front wheels, and the P34 made its competition debut at the 1976 Spanish GP. In qualifying, Patrick Depailler finished third, well ahead of teammate Jody Scheckter.

Scheckter switched to the P34 and led the six-wheeled machine to pole position at the Swedish GP that year, leading to a 1-2 finish for Tyrrell. But the P34's success was short-lived; the 1977 race was less successful, and in 1978 Tyrrell reverted back to a four-wheel design. Scheckter went on to win the F1 drivers' championship with Ferrari in 1979. The team raced for the last time in 1998, but its assets were used to establish the current Mercedes-AMG team.

The P34 is the only six-wheeler still competing in F1 today. March and Williams tested six-wheelers but never raced them. Also, unlike the P34, those designs used conventional-sized wheels all the way around and had two powered rear axles and one unpowered front axle. In other words, the P34 is truly a one-off unicorn design.

The chassis number 8 car being auctioned is from Scheckter's own collection. However, it is not the car he raced; it was assembled by Paul Lanzante in the 1990s as a spare tub and turned into a complete car.

RM Sotheby's expects chassis number 8 to sell for 450,000-650,000 euros, or roughly $485,000-700,000 at current exchange rates. While it may not have a competition history, the rarity of this car should justify its eventual high bid.