Shifting weight forward in a racecar to improve turn in is a know fact. The reason for change in tire traction is heat generated in the contact patch and change in surface temperature of the tread rubber. Classic tire side force / load or side force / slip curves do not predict dynamic performance at car turn-in improves when weight is shifted forward. This fact alone shows that the classic tire side force/load/slip curves should not be used for dynamic analysis. The classic curves are representations of steady state data. Most tire traction data is not theoretically correct for dynamic solutions. Traction force change in tenths or fractions of a second is required for dynamic analysis. These data do not exist. For dynamic changes tire surface temperature remains constant for one wheel revolution for sure, and near constant for several revolutions. The Hallum Tire Model (HTM) is for isothermal conditions and is correct at any constant temperature (profile) condition. HTM predicts that side force(traction) increases more than load initially during transient response. Thermal modelling of the tire (the next Hallum Racing paper)and comparison to real data may lead to additional discoveries. HTM only considers the tread. Work to include carcass parameters must be added before a true dynamic model of the tire is complete. HTM logically introduces heating to tire performance analysis. Why heat generation has not been considered in the past is unknown. All racers and people in the tire field know that temperature affects grip and limits maximum tire performance. HTM is simple allowing one to 'see' and understand how heating affects tire performance. Tracking the path of a tread surface particle through the CP using the HTM slip/re-grip hypothesis explains numerous tire performance phenomena. Parameters measured in tire tests must include tire surface temperature (before and after the CP) during the test and bulk temperature immediately after the test. Within a few years all books on tires will have a new chapter on how heating affects tire performance.
Dynamic traction characteristics of tires
Dynamische Zugkraftcharakteristik von Reifen
2002
13 Seiten, 17 Bilder, 2 Tabellen, 9 Quellen
Conference paper
English
Dynamic Traction Characteristics of Tires
British Library Conference Proceedings | 2002
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