SUV tires don't have the speed rating that performance tires have. It could be dangerous at high speeds. I also believe the side wall compound might be different but I could be wrong.
Tire ratings:
http://www.driversense.com/driversense/column/357
Rubber compound (SUV vs passenger cars):
http://www.ehow.com/about_5575266_pa...-suv-tire.html