I own a Team Associated RC10gt, which is a 1/10 scale nitro truggy and/or truck. I took an old tired off of one of the wheels, used a caliper to measure the dimensions of the wheel, and deigned it on Solidworks. I will be making more variations of the standard wheel to come. hopefully the measurements to work well on my/your rc car (if you decide to print it on a 3D printer like I will be). Let me know how it works if you make one!

Apparently there has been some trouble with sizing (inches to millimeters) and should be around 2.4"x2.4"x1.96" while it is sitting on flat front part of the wheel. If it is too small, because of millimeters, then size it up by 25.4.