If an axial that spins at a fixed rpm has an 8" tires attached and another identical axial spinning at the same rpm has 10" attached to it. Do the 10" tires move the vehicle faster or the same speed?

Think about the speed of the outside edge of the wheel. There's a formula for that:

v = r \omega

where \omega is the angular velocity in radians/second. So can you tell form this whether the outside of the wheel moves at the same speed if r=10" versus r=8"?

Lets get real absurd. Instead of an 8" tire, you have a 1" tire. Now what do you think? Picture it in your mind and, in addition to velocity, remember formula for a circumference: Pi X d. How much distance is covered in 1 RPM? Should be easy now.