Sun Mountain Hi Performance Foam Tire Kit If you have a Sun Mountain Speed Cart with pneumatic tires and are tired of adding air or replacing flat tires, then you'll want to upgrade to the Hi Performance Foam Tires found on the latest Sun Mountain Speed Carts. Replace your inner tube tires on your V1 Sun Mountain Speed Cart with the Foam Tire kit. The kit includes 3 tires w/rims. Kit also replaces wheels on Sun Mountain SV1 and GT Speed Carts.