I used 3 ". They work niceley. I used socket head allen bolts for the axles. I tried regualr bolts at first but they kept bending. All though if I had to do over I would get 3 1/2". The 3's sometimes get stuck in the grass at the field when it's not freshly mowed. Then I have to carry the plane to the run way.

I like this plane, its awsome for the price!


Wings