What is Trading Paints Downloader and why do I need to use it?

Since iRacing does not automatically load custom car paints, you’ll need to install and run Trading Paints Downloader, the program that loads paints from Trading Paints onto cars in iRacing when you race.

When Trading Paints Downloader is open while you race, iRacing gives Trading Paints a list of cars in the session that require custom paints to be loaded. Then, Trading Paints Downloader fetches the paints corresponding to each car in the server and loads them into iRacing. After a few moments, custom paints will begin to appear on cars you see in the server.