I ran into the same problem with the WM Super Sports 40. The standard wheel size that works well at our field is 3". The axles are too short to mount 3" wheels on them. I had to cut off the axle off and add an Easy Adjust axle to the wire section that comes down from the wing. Now you can't use the retracts without mods. Thats why retracts on a grass field aren't such a great idea either!! Don't lnow if you know it, but its standard practice to use full up elevator when taxiing to keep the tail down. [8D]