i use 1/4-20 Nylon bolts for all wing hold downs. I have always used them for the landing gear also till this last week. I have sheared off several on landing and didnt land that hard. The gear broke off each time wihtout damage to tail feathers as usually happens. i switched to steel, heavier but wont break. I doubt if any more damage occurs wiht steel thant nylon. Nylon deteriorates in the Ariozona sun if you ask me. Especially if the heads dont seat at the exact angle to the item being secured. Stressed heads just pop off and that was my trouble. I had installed a wedge and the heads tightened down securly but popped under stress with a 13 lb. airplane. My .02cents worth.