/diy/ - Do It Yourself

Hey /ohm/ my professor wants us to race line following robots. Only the fastest car can get an A in his class. Normally, I'd do this entirely myself but there's a lot riding on being the best.

Anyway, most line follower racers I've seen have two wheels with sweep in front like pic related. My professor is strongly urging us to purchase an rc car and rig it to be a line followed racer (ie 4 wheels). The track is carpet with white tape.

Is there any advantage to 4 wheels or disadvantage to the common 2 wheel design? If 4 wheel designs are better, why is every single design I see at world championships 2 wheels?