When I was a kid I had Hot Wheels cars and lots of race tracks. To keep a car on the track, Hot Wheels tracks have raised sides that form a gutter of sorts that the car sits in. My friends and I used to build enormous tracks in the basement and race cars against each other. Most of the cars we raced were old, beat up things that we kept in a coffee can and sometimes drove around on the concrete patio outside. As a result, the wheels were all bent in slightly different directions. As the cars went down the track, the would wobble. They would rub against the side of the track. Sometimes they were bent so badly that the cars would get stuck on the race track.
One day I tried a brand new car, just out of the package. This car was the fastest car we’d ever seen on our track layout. We went and grabbed some other cars that we knew were fast, but none could match the new car. When we were done, instead of putting the car in the coffee can with the rest of them, I put it on a shelf in my room so I could quickly find it again next time we raced.
It worked fine for a couple of races, but then I played with it on the floor a bit. The axles bent a little, and it never ran straight again.
A fast car has straight wheels. The single greatest thing you can do for the speed of your car is make it go straight. If the wheels aren’t aligned it will wobble. It wlll rub against the center guide of the track. One of the wheels will drag like a broken cart at the supermarket. And all these things will slow you down a lot.
Sometimes I’ll see the unlikeliest winner at a pinewood race. The car is ugly, the shape is all wrong, and it has weights haphazzardly glued to the car. The car is obviously built by a kid with no experience. But it still wins. The reason is usually because the kid got lucky when he put his wheels on. By random chance, his wheels ended up completely straight.