Hi,

I use Du-Bro Super Lite Wheels (2-3/4 inch diam.) on my MythoS 125E. Works great. I fly on grass.
Since I fly off rough grass I use slightly larger wheels then I otherwise would use (about 2-1/2 inch I would use otherwise).
Although I have MK Super Light Wheels (60 mm) and MK SkyBlue SuperLight Tyre (60 mm) also I have not tried them but they seems to be good quality as far as I can judge.
They all have 4 mm hole for the axel.
Some pictures and weights below. Second last picture show my tyre after about 100 flights on grass.
Hope it helps.

/Bo