There were about seven variants of the G-103 (Twin II, Twin III, Acro models etc.) To my knowledge, all are fixed gear with the exception of the Twin Astir, which has an unusual sideways folding main wheel. If this is what you have, I suggest you contact Robert Mudd at Composite Aircraft Repair in Moriarty, NM. (There is an ad in the back of Soaring Magazine.) Robert is out of the country at present, so a response may not be immediately forthcoming.