Can you use a smaller tire on the 2006 ford escape?

Of course you can, but it will effect handling, braking, performance, and fuel mileage, plus your speedometer will no longer be accurate. My advice is to stick with the OEM size tire. Saying that you can change sizes if you choose a tire that has the same overall diameter as the OEM tire. For instance if you OEM size is 235/70-16 you can install a 215/75-16 which would have almost the same overall diameter as OEM.