Physics of Racing:Some useful Links:
Brian Beckman: The Physics in Games - Real-Time Simulation Explained
Brian Beckman has worked on the tyre physics of Forza and is here explaining some basics of Real-Time Simulation and of tyre physics.
Rally Cross Physics
Hardwire's Game Physics Resources - Car physics
A Collection of some useful Links to this topic.
An open source car simulation project.
The only source where I understood Pacjeka's Magic Formula. Not the theoretical part of the formula, but it was the first source where I found the formulas in a form that I could implement in my demos.
The Physics of Racing
A series of some very good articles.
Marco Monster (Car Physics for Games)
Link to the Internet Archieve Wayback Machine, because the original page is offline (or go to my Mirror).
2D Car Physics
Links to some Threads in the GameDev.Net Forum (that can be helpful if you want to read some opinions about this topic. There are some very helpful statements for a start into this topic, too):
How to calculate the correct amount of friction
Race Car Physics
Simplified Pacejka Magic Formula
Help creating arcade racing simulator
Help with simple 2D car physics
avoiding vibration of car