This "solid paper" you’re likely after isn't just one document but a collection of industrial and academic research used to build the sim's realistic tire and bike behavior:
If you are specifically looking for a .rar file of these papers, be aware that many of these are copyrighted academic texts or proprietary industrial data. You can find high-level summaries and purchase options for Cossalter's work on major academic publishing sites. Are you trying to for a specific bike, or TrackDayR – The Unleashed Sim trackdayr.rar
: The game integrates various validated industrial formulas to replicate accurate motorcycle movements rather than using simplified "arcade" physics. This "solid paper" you’re likely after isn't just