I feel like new wheels are more vulnerable to flat spots. I like to break them in a bit before I try tricks. Bomb a few hills, rough 'em up, then slide them around a bit. Not sure if there's any science to this but it seems to work for me as I had a run of flat spotting brand new wheels. Also all the flat spots I've had on F4s have been relatively small and work themselves out pretty quick. Unlike say with an SPF, whereby, once flat spotted it takes a lot to get them round again....