ORIGINAL: el_tonto
It would only matter if you want to compete, otherwise it's just an approximate indicator. The "1/10th" Rustler and Stampede both have a wheelbase approaching 12" or so, so if you're between 10" and 12" then I'd safely call it 1/10. I think the maximum track for racing is about 12.5" (outside wall to outside wall, at static ride height), and even with those enormous tires I don't think you'd exceed that.
OK. I measured from front axle to rear axle and I am at 10.5"
I would never think about using this truck to compete. I only did this out of sheer enjoyment of building one. I had so many ideas to use these SH12's in, but never got around to doing anything untill now.
Thanks for the info buddy!