New Wheel Sizing

Hello everyone,

Whilst looking on the vex store I noticed there were new traction wheels labelled as “320mm travel”. Additionally, there were 320mm travel omni wheels as well. Both of these wheels are listed under the 4 inch. category. I was wondering whether or not the diameter of these new wheels are the exact same. Does the 320mm travel refer to the distance moved after 1 revolution? As it was before, the omni wheels happened to be slightly larger than the the traction wheels, meaning that a 6 wheel drive base with 2 traction wheels in the middle and 4 around wouldn’t be possible. If you have the new wheels, could you check to see whether or not the sizing is the same now?

Much thanks


Yes, “320 mm travel wheel” means the robot will travel 320 mm in one revolution of the wheel (i.e. the wheel circumference). 4\pi inches is 319.2 mm so that makes sense.

The diameter of a wheel exactly 320mm around would be 101.9 mm \approx 4.01 inches. Even if the old wheels were exactly 4.00 inches in diameter, the difference of 0.01" is roughly the width of 3 human hairs according to Wolfram|Alpha, probably negligible.

I always found it a little weird that IQ wheels were listed by their circumference in mm, while EDR/V5 wheels were listed by their diameter in inches, so it’s nice to see that they seem to be standardizing on one of those.


I actually don’t like the change. People in VRC are used to measuring wheel size as either 2.75, 3.25, 4, or 4.125 inches. Also, hole spaces in VRC are measured in .5 inch increments so it is easier to figure out spacing, and field tiles are 24 inches so imperial works better for distance.