I've never actually measured them out, but it looks about the same. However, the inner diameter is a little over the SCX24 standard 1.0. The tires are decent, but no where as soft and tacky as RC4WD.
You're still up on me, in expertise, with those fancy calculations. Perhaps the FCX24s are more true to scale than the SCX24s. But my opinion still remains the same in regards to scale discrepancy when using pics from @Doom! #15 post. There's no denying those photos. Significant size difference...
Different scale classes. That FCX24 is NOT a 1/24 scale, more like 1/18 scale! Its like comparing apples to oranges.
I don't have the FCX24, but I do have 2 of the Atlas', and while they are good crawlers, they are not as well designed as the SCX24s. I hear a lot about issues with the stock...