Motor and wheels?

I am starting think of a robot chassis for 2018-2019 but what size wheels should I use and how many motors (what gear ratio) should I use if I want a pretty fast robot.

The 2018-2019 game hasn’t even been released, so based on what the game is different size wheels and gear ratios may be appropriate. But usually a good fast robot is either HS 2:1 external with 4" wheels and 6+ motors, or direct turbo motors on 4" wheels with 6+ motors

Thanks-have to start thinking some time

My team uses this VERY refined 6 motor HS 4" chassis every year, as it is super low profile and is very diverse. We have never had to change it.