Kathy - if you don't need to show the car accelerating, just make the wheels sort of blurry and spinning - if you watch a car on a highway you can't really tell that the wheels spin at EXACTLY the same speed as the road going past. If you want to start animating at a standstill and then accelerate, that might be trickier. Can you measure around the wheel, then stretch that distance out flat so that a marked point on the wheel hits the road at that interval each time? Then regardless of the speed of the car the wheels will move exactly how they should...i hope this made sense....long day....