Max load of Tamiya 70097 Twin-Motor Gearbox Kit

Ok so I purchased the Tamiya 70097 Twin-Motor Gearbox Kit. I would like to know how much weight can this thing carry comfortably. I am using this for a school project and i need to do the calculations.
Any feedback would be apprecited!

“Comfortably” is subjective. The Tamiya kits aren’t industrial products and don’t have any kinds of ratings on their operating life. In general, your results will depend on a variety of factors, including how you drive the motors (how violently you switch directions, how much acceleration you expect, etc.) and what gear ratio you’re using. A general ballpark for a practical limit is a few pounds, and that assumes some of the weight is on a third contact point.

- Jan