I’ve always wondered, when I watch races online, especially in Europe in KZ karts I see the drivers put their hands on their rear tires and roll them back and forth while waiting for the race to start. I thought it was to keep the water pump moving to cool the engine but they move the kart such a tiny amount I figured it couldn’t do anything. Why do they do this?
Thank you!
It prevents the tires adhering\flattening too much in one spot… Help ensure you get a good launch.
Probably not as necessary as it used to be but it’s make sure the tires don’t get stuck to the surface.
Isn’t first easier to select after a bit of movement too. I can’t remember been a while since I drove one.
It helps tremendously keeping the tires from locking down too much. Helps get that little bit of slip needed when launching. I notice a huge difference when I do and don’t do it, which is why I always do it.
Thanks for the replies, makes sense now!
It’s also looks cool 
I find that rolling the kart backwards a little and then forwards into position keeps the motor from having difficulty engaging first gear. If you don’t do it, the motor sometimes will be stuck in a false neutral making it difficult to make that quick gear selection. My TM K9B was bad for this but the Vortex Rok less so.