On the subject of Field Approvals for main or tail wheels...

Field approvals have indeed become more difficult in recent years but of all things tire modifications and especially tail wheels on general aviation aircraft don’t seem to be the subject of any intense scrutiny. Tundra tires in general are the only field approval for which there is a system in place for application to the FAA. The Tundra tire work sheet is part of the fairly effective established system. We still do them pretty regularly and also have an LDER on staff to help if needed.