If you just refer to it as a 14mm hex or 17mm hex, its pretty clear what you're talking about.....

I know its more expensive, but you can change wheels too - as long as they're 14mm hex, they will work.
I wanted lightest weight wheels/tires to reduce rotating weight and get the most reponse from the motors. Reason I went with SportTraxx wheels and tires. That dropped a bunch of weight off of my 3906, making it much more responsive.