Subject: Does wheel size affect a car's speed if you keep everything else constant?

The car is going to be propelled by gravity. I am going to set a car at the 
top of a ramp and release it.  I will time it's speed and then I will repeat 
the process with a different size wheels.    I am going to make the car out of 
Legos. I will be keeping mass, height, road surface, aerodynamics constant.  I 
have done a lot of research but I have not found anything that relates to my 
question.  All the web-sites and books I have found discuss the effects of 
aerodynamics on speed, how the mass of the car affects speed, how the road 
surface affects speed and how the heat of the tires affects friction.  The 
stuff I have read makes me think the wheel size won't matter, but I don't 
really have the physics to back up that idea. 

Re: Does wheel size affect a car's speed if you keep everything else constant?