Jeff C - The Yokomo wheel hex's work just fine, but the hole for the axle has to be reamed out a little bit for the US spec axle to fit (vs. metric). Another thing to watch out for is the fact that the Yokomo Drive pin is quite a bit fatter than that of the Losi...creating slop and backlash in the axle - which I am sure will not aid in longevity of the axle!
Wilde