[Ben Piecuch]

Thanks for clarifying the drive train.

With that information, omniwheels are probably your best choice in this situation, due to weight and time contrainsts. If the weight of your robot is equally balanced between the front and the back (a 50/50 weight distribution) then it doesn't matter which side you put the omniwheels on. Basically, it would come down to the driver's preference as to which end of the robot gets rotated. I would suggest looking at some video of FRC176 this season. They are using omniwheels on the back of their robot, and you can see how it significantly changes the style of driving.

If the robot is significantly heavier on one side or the other, it is advantageous to put the omniwheels on the lighter side of the robot. With your traction wheels on the heavy side, you will transmit more power to the ground, and the robot will turn even easier.

Having the 4wd setup has already provided a huge step up in performance, as you probably realized during testing with the lighter kitbot setup. Mounting a chain and sprockets to some of the cheaper, generic omniwheels is a little more complicated than just a drop in solution. I feel that the Andy-Mark 6" omniwheel is your best solution, as those wheels are a direct replacement for the existing 6" wheels.

One other solution, which may not be widely accepted here, is to find an old 6" skyway wheelchair wheel. These are the old kitbot wheels which teams used in previous years. They are not as grippy as the new kit wheels, and could provide you the right balance between side slip and lateral grip. With the proper wheel hub, these are also a direct drop-in solution.

Best of luck.

BEN