4x4 uses hexes, but the original and FT SC10's (at least when I bought mine 18 months ago) use a pin in the back and bearings up front (so I, for example, have three types of wheel to outfit my two SC10s). The new SC10RS comes with hexes as standard. So all of this to say, you may need to change over to hex wheel mounts depending on the vintage of your SC10.