You need (42) 5x8x2.5mm bearings for the wheels and suspension arms inside the lower hull. Could look on ebay such as this.
http://www.ebay.com/itm/Extreme-Hobb...gAAOSwmrlU0l0c
Or sealed bearings like these.
http://www.ebay.com/itm/Apex-RC-Prod...cAAOxyA9dSU5W3