Anyone have any solutions for the tires.
I try to run these on the floor in the room and the halls and they just slip so often.
Any suggestions
I’ve had students place their cellphone on the back, which helped (and not a good solution). We considered 3d printing posts that would snap onto the frame and hold two sets of washers between the rear wheels.
Has anyone solved this in an elegantly simple way?
Hello, I too am having problems with the wheels slipping. I’m trying to use it on a dry erase board so I can put the dry erase marker in the XRP and draw shapes. I have to set the effort down to 0.3 so that the wheels don’t slip (and the still do slightly), but the XRP can barely move itself with that amount of effort. At 0.2, it doesn’t even move itself on a dry erase board. I’ve thought of weighting it down somehow, but if others have a good way, I’d like to hear ideas before I fabricate something myself. I also thought about coating the tires in Coca-Cola. I hear rock bands put it on stages so they don’t slip off. 
Any other ideas??