Intro to Racecar Engineering: 13 Tires

Smitty shares tips of the trade regarding tires. This is the thirteenth video in a series developed for UCI's racecar engineering program. (Smitty and the Professor series)
mechanicaldesign101.com/smitt...

[@patricksquires6348]

Used to CAD some race spindles years ago. Another bit in the whole castor, camber, steering axis inclination, is also the steering arm on the spindle and steering mechanism. Focusing on the spindle itself the arm if the rod is a straight push/pull is that arm should angle from center spindle and axis meet to the center of the rear of the car or forward. as you push on the outside spindle and pull on the inside spindle the rate of change of each spindle will turn at different speeds some . This will allow for tighter turning radius on the inside wheel vs the outside wheel. This allows for less scrub thus better traction. Great videos - Your YT video is of only a few that shares details such as geometry under load should be accounted for. More areas of detail that affects steering geometry is pivot axis location and length of arms attached to spindle.

[@slowinfastout3304]

Hi, I’m curious which has more contact patch between a taller and wider tire. For example 255/40R18 vs 265/35R18? Also if I move up in tire size, does it mean it requires less air pressure? Thanks in advance !

[@Zickcermacity]

Hi SiFo: Robert Pepper has your answer. Succinctly, with wider, lower profile tires vs skinnier, higher profiles, it's the orientation of the patch area that will change the most - by a factor of at least 4:1. Given the same cold tire pressure in both: A narrow, higher profile tire will have a narrow, longitudinal patch. That is, parallel to the direction of travel. A wide, lower profile tire on a monster rim will have a wider, lateral(perpendicular to travel direction) contact patch. The contact patch on the wider tire/wheel package might be, at most, 5-10% larger than on the narrower package, but its orientation is what will affect your handling and feel, the most. And herrrrre, is Mr. Pepper's explanation. While his primary audience is off-roaders, the information here carries over to the street as well: m.kzbin.info/www/bejne/qaGyhpaXit98frs