www.jimmyjeep.com has a lot of info out push trucks, I've only ran over 1 tire & that was to keep from ramming the car cause it died. I've worked for Must See Racing pushing at Winchester. Worked w/ those nutballs who push at Eldora there, lotta fun but you gotta keep your eyes open & totally concentrate on what you're doing. I built a push ????? bug?? w/ a spring loaded bumper, my driver loved it. Said never felt a thing, said he waved & away we went