I had the same problem with mine. I tried putting a 1/4in. shim under the rear gear wires to rotate the wheels forward a little. It didn't help much. I think the grass is the biggest problem. I went out one day last week right after the grass was cut on our field and had two perfect Cub-type take-offs. Before, I was flying on Sunday when the grass was cut on Friday. We have a kind of grass in the South called bahia that can grow an inch in one day. So with a little rain and some heat it was growing enough in two days to drag the wheels back and make it nose over. Cooler weather is coming and the grass will slow down. I'll try more tests then. :-)