WIRED published an article today outlining a lot of the science behind our beloved hobby. It gets pretty deep in the weeds with all the physics and formulas but it all boils down to that in end, I guess.
It even talks about why cars may tend to turn and drift. Yes, it's about the forces being applied unevenly on the wheels. But that can also happen because your axles aren't straight...but of course, you have your own axle alignment jig so you're not worried about that too much. Wait. You don't have a jig? Well, the Redline Derby alignment jig can help.
Okay, shilling aside, I always find the science of downhill racing pretty fascinating because it's really all so simple. I mean, it makes sense when you read it but then why is it so hard to nail down when you're building a car? Easy to understand, hard to master...like any good challenge.
And if you're looking for some more math and science, check out the video from Mark Rober from a few years ago. He makes it pretty friendly and also gives you a Top 10 list of things that make a difference when building a car.