Just thought of this; I bet your car is heavier than mine. It's also geared WAY higher. That may explain why you don't have the same issues with traction.
My car weighs 9lbs 13oz
The tires will completely spin if I give it full throttle. Its too much torque even with that gearing. Its around 1.7:1 for a final drive ratio. 64 pinion/36 spur.